Improve ferromanganese smelting processes using benchmarking techniques
- Sedumedi, B. Kaelo, Pan, Xiaowei
- Authors: Sedumedi, B. Kaelo , Pan, Xiaowei
- Date: 2014
- Subjects: Benchmarking (Management) , Ferromanganese alloys
- Type: Article
- Identifier: uj:4777 , http://hdl.handle.net/10210/11960
- Description: It is well known that ferromanganese alloys are used to help produce all types of steels. Manganese ore prices are closely associated with those of iron ore prices. The production of high quality ferromanganese has become increasingly important in the context of fluctuations in the iron ore price in global markets. In appreciating the importance of benchmarking the various ferromanganese production practices worldwide have to be identified to develop methodological aspects. Firstly the standard production variables would be reconfirmed, and identify new ones given the various sophisticated production environments. In other words, are there unique variables to specific production facilities? Secondly, appropriate benchmarking method(s) would be recommended given the production objectives in existence. Inductively, all the variables, both metallurgical and non- metallurgical would be condensed into concepts or particular benchmarking techniques.
- Full Text:
- Authors: Sedumedi, B. Kaelo , Pan, Xiaowei
- Date: 2014
- Subjects: Benchmarking (Management) , Ferromanganese alloys
- Type: Article
- Identifier: uj:4777 , http://hdl.handle.net/10210/11960
- Description: It is well known that ferromanganese alloys are used to help produce all types of steels. Manganese ore prices are closely associated with those of iron ore prices. The production of high quality ferromanganese has become increasingly important in the context of fluctuations in the iron ore price in global markets. In appreciating the importance of benchmarking the various ferromanganese production practices worldwide have to be identified to develop methodological aspects. Firstly the standard production variables would be reconfirmed, and identify new ones given the various sophisticated production environments. In other words, are there unique variables to specific production facilities? Secondly, appropriate benchmarking method(s) would be recommended given the production objectives in existence. Inductively, all the variables, both metallurgical and non- metallurgical would be condensed into concepts or particular benchmarking techniques.
- Full Text:
Effect of South Africa chrome ores on ferrochrome production
- Authors: Pan, Xiaowei
- Date: 2013
- Subjects: Ferrochrome production , Ferroalloy process optimization , Chrome ore
- Type: Article
- Identifier: uj:4729 , http://hdl.handle.net/10210/11555
- Description: About 80% of world chrome ore reserves are found in South Africa, mainly in the Bushveld Igneous Complex. Chrome ores from six locations across the Bushveld Complex are used to investigate the effects of ore types on the smelting processes, such as the consumption of fluxes, reductant; and most importantly, the consumption of electricity...
- Full Text:
- Authors: Pan, Xiaowei
- Date: 2013
- Subjects: Ferrochrome production , Ferroalloy process optimization , Chrome ore
- Type: Article
- Identifier: uj:4729 , http://hdl.handle.net/10210/11555
- Description: About 80% of world chrome ore reserves are found in South Africa, mainly in the Bushveld Igneous Complex. Chrome ores from six locations across the Bushveld Complex are used to investigate the effects of ore types on the smelting processes, such as the consumption of fluxes, reductant; and most importantly, the consumption of electricity...
- Full Text:
Influence of oxygen gas on the improvement of energy efficiency in induction furnace using foaming slag
- Kipepe Mwata, Theodore, Pan, Xiaowei
- Authors: Kipepe Mwata, Theodore , Pan, Xiaowei
- Date: 2015-05
- Subjects: Energy efficiency , Foaming slag , Induction furnace , Oxygen gas
- Type: Article
- Identifier: uj:5162 , ISSN 1021447x , http://hdl.handle.net/10210/14313
- Description: Since many years, the world has come together to face the challenge regarding the energy consumption and energy efficiency problems. In order to achieve and overcome these challenges, researchers have been focused on one of the most energy demanding sector worldwide which is the Industrial sectors and more specifically the Foundry. South Africa being one of the countries having the cheapest price of electricity and has brought a misusage of electricity and thus brought inefficiency in the industries and increase of prices in foundries. The purpose of this paper is to show the importance and impact of oxygen gas in the creation of a foaming slag during the melting process induction furnace (IF). Results have ! shown an optimum of oxygen gas injection of 100ml/sec and from 50 to 42 min which is a gain of almost 12 min in time (21% - 23.5%) and electrical energy consumption from 18.41kWh to 13.93kWh have been reduced to 2.56%. The thickness of slag foam increases from 0.2 - 0.9 cm during the experimental process and decreases the temperature on the surface of the foaming slag from 912°C to 878°C. As such, a simple heat transfer modelling and calculation have been conducted to see the impact and the relation between the heat loss and the foaming slag and result as shown that the heat saving was made from 9.1 - 9.2%.
- Full Text:
- Authors: Kipepe Mwata, Theodore , Pan, Xiaowei
- Date: 2015-05
- Subjects: Energy efficiency , Foaming slag , Induction furnace , Oxygen gas
- Type: Article
- Identifier: uj:5162 , ISSN 1021447x , http://hdl.handle.net/10210/14313
- Description: Since many years, the world has come together to face the challenge regarding the energy consumption and energy efficiency problems. In order to achieve and overcome these challenges, researchers have been focused on one of the most energy demanding sector worldwide which is the Industrial sectors and more specifically the Foundry. South Africa being one of the countries having the cheapest price of electricity and has brought a misusage of electricity and thus brought inefficiency in the industries and increase of prices in foundries. The purpose of this paper is to show the importance and impact of oxygen gas in the creation of a foaming slag during the melting process induction furnace (IF). Results have ! shown an optimum of oxygen gas injection of 100ml/sec and from 50 to 42 min which is a gain of almost 12 min in time (21% - 23.5%) and electrical energy consumption from 18.41kWh to 13.93kWh have been reduced to 2.56%. The thickness of slag foam increases from 0.2 - 0.9 cm during the experimental process and decreases the temperature on the surface of the foaming slag from 912°C to 878°C. As such, a simple heat transfer modelling and calculation have been conducted to see the impact and the relation between the heat loss and the foaming slag and result as shown that the heat saving was made from 9.1 - 9.2%.
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Challenges and developments of Hadfield manganese steel castings based on service life
- Authors: Mahlami, C.S. , Pan, Xiaowei
- Date: 2014
- Subjects: Austenitic manganese steel , Hadfield manganese steel castings
- Type: Article
- Identifier: uj:4775 , http://hdl.handle.net/10210/11958
- Description: Austenitic Manganese steel has a high toughness, high ductility, high strain hardening capacity and an excellent wear resistance. This grade of steel is mostly used in the mining industry for crushing and loading equipment. The present paper highlights the challenges and the development of high manganese steel casting based on the service life. Currently the challenge faced among others is the rate of work hardening, which is due to the crushing efficiency of the modern jaw and cone crushers. This limits the rate of work hardening produced on the surface of the metal thus resulting in low wear resistance, loss of material and cost of production for secondary and tertiary crushing equipment. Due to this challenge faced, researchers were motivated to come up with innovative ideas and new development that will increase the hardness and wear resistance of the said steel, resulting in longer service life of the components. These developments include the introduction of a new heat treatment procedure, the addition of micro alloying with Chromium and the use of metal matrix composite on manganese steel casting. However, the introduction of these new developments on high manganese steel casting showed to have a direct increase in wear life and hardness of the steel.
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- Authors: Mahlami, C.S. , Pan, Xiaowei
- Date: 2014
- Subjects: Austenitic manganese steel , Hadfield manganese steel castings
- Type: Article
- Identifier: uj:4775 , http://hdl.handle.net/10210/11958
- Description: Austenitic Manganese steel has a high toughness, high ductility, high strain hardening capacity and an excellent wear resistance. This grade of steel is mostly used in the mining industry for crushing and loading equipment. The present paper highlights the challenges and the development of high manganese steel casting based on the service life. Currently the challenge faced among others is the rate of work hardening, which is due to the crushing efficiency of the modern jaw and cone crushers. This limits the rate of work hardening produced on the surface of the metal thus resulting in low wear resistance, loss of material and cost of production for secondary and tertiary crushing equipment. Due to this challenge faced, researchers were motivated to come up with innovative ideas and new development that will increase the hardness and wear resistance of the said steel, resulting in longer service life of the components. These developments include the introduction of a new heat treatment procedure, the addition of micro alloying with Chromium and the use of metal matrix composite on manganese steel casting. However, the introduction of these new developments on high manganese steel casting showed to have a direct increase in wear life and hardness of the steel.
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Learning and teaching using process modelling and simulation
- Authors: Pan, Xiaowei
- Date: 2015
- Subjects: learning , Teaching , Process simulation
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/72809 , uj:18330 , Citation: Pan, X. 2015. Learning and teaching using process modelling and simulation.
- Description: Abstract: Depending on the way of teaching, teachers can make enormous difference in the quality of learning and teaching at university. This paper covers how to use process modelling and process simulation to help students to understand some of the complex industrious processes easier and better. Many industrious processes, such as the production of ferrochrome, are extremely complicated and often those processes are interacted and involve many physicochemical reactions that happen simultaneously. When there is any change in one of the inputs, it usually requires to understand the potential effects on the production processes and then decide what actions should be taken to accommodate the change of the mentioned input, in order to manage the production processes to achieve the desired target. Due to the complexity of the production, it takes many hours to complete a charge calculation, which involves with the calculation of mass and energy for the entire furnace. Using process simulation built with process models, it is possible to carry out many what-if scenario exercises in classroom, resulting in easier and better understanding of the cause-effect relationship existing in the production of ferroalloy.
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- Authors: Pan, Xiaowei
- Date: 2015
- Subjects: learning , Teaching , Process simulation
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/72809 , uj:18330 , Citation: Pan, X. 2015. Learning and teaching using process modelling and simulation.
- Description: Abstract: Depending on the way of teaching, teachers can make enormous difference in the quality of learning and teaching at university. This paper covers how to use process modelling and process simulation to help students to understand some of the complex industrious processes easier and better. Many industrious processes, such as the production of ferrochrome, are extremely complicated and often those processes are interacted and involve many physicochemical reactions that happen simultaneously. When there is any change in one of the inputs, it usually requires to understand the potential effects on the production processes and then decide what actions should be taken to accommodate the change of the mentioned input, in order to manage the production processes to achieve the desired target. Due to the complexity of the production, it takes many hours to complete a charge calculation, which involves with the calculation of mass and energy for the entire furnace. Using process simulation built with process models, it is possible to carry out many what-if scenario exercises in classroom, resulting in easier and better understanding of the cause-effect relationship existing in the production of ferroalloy.
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Automated mine optimization system for diamond mines
- Authors: Pan, Xiaowei
- Date: 2013
- Subjects: Process optimization , Process control , Soft sensor , Smart sensor , Diamond mines and mining
- Type: Article
- Identifier: uj:4733 , ISSN 2277 – 4378 , http://hdl.handle.net/10210/11559
- Description: A diamond mine generally consists of mining and mineral beneficiation operations. Mining operation includes planning, drilling, explosion, loading; hauling and mineral processing normally has the following operations: crushing; screening; washing; transporting; separation; sorting; storing; water treatment, etc. The operation could be described as a complex and expensive balancing act where material flow rates, size, density and other factors must all be in required balance if any degree of plant optimization and efficiency is to be achieved. One of the main objectives to optimally operate a mine is to maintain balanced production among all product streams. To achieve a balanced and optimal production at a mine, two tasks at least must be considered. The first is to have an optimal production plan, including a set of optimal production targets for all process units. And the second task is to make sure that all those optimal targets in the mentioned optimal production plan must be achieved at all process units by using all resources available. To achieve the mentioned two tasks, all measurements, equipment and systems at the mine must be available in real time, particularly those critical measurements such as weightometers, densitometers, ore types; stockpile levels. With the advancement and applications of technologies in mineral processing industry, an automated mine optimization system is developed to include the following three functions: (1) mine production optimizer; (2) various dynamic controllers; and (3) a set of soft sensors. Over the past ten years, a large amount of work has been done to develop the system, started from forming the concept to testing and implementation at various mines. The system can potentially help improve the production throughput up to 30% at the mineral processing operation of a mine.
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- Authors: Pan, Xiaowei
- Date: 2013
- Subjects: Process optimization , Process control , Soft sensor , Smart sensor , Diamond mines and mining
- Type: Article
- Identifier: uj:4733 , ISSN 2277 – 4378 , http://hdl.handle.net/10210/11559
- Description: A diamond mine generally consists of mining and mineral beneficiation operations. Mining operation includes planning, drilling, explosion, loading; hauling and mineral processing normally has the following operations: crushing; screening; washing; transporting; separation; sorting; storing; water treatment, etc. The operation could be described as a complex and expensive balancing act where material flow rates, size, density and other factors must all be in required balance if any degree of plant optimization and efficiency is to be achieved. One of the main objectives to optimally operate a mine is to maintain balanced production among all product streams. To achieve a balanced and optimal production at a mine, two tasks at least must be considered. The first is to have an optimal production plan, including a set of optimal production targets for all process units. And the second task is to make sure that all those optimal targets in the mentioned optimal production plan must be achieved at all process units by using all resources available. To achieve the mentioned two tasks, all measurements, equipment and systems at the mine must be available in real time, particularly those critical measurements such as weightometers, densitometers, ore types; stockpile levels. With the advancement and applications of technologies in mineral processing industry, an automated mine optimization system is developed to include the following three functions: (1) mine production optimizer; (2) various dynamic controllers; and (3) a set of soft sensors. Over the past ten years, a large amount of work has been done to develop the system, started from forming the concept to testing and implementation at various mines. The system can potentially help improve the production throughput up to 30% at the mineral processing operation of a mine.
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Quality investigation of austenitic manganese steel blades
- Dipale, Anicia, Pan, Xiaowei
- Authors: Dipale, Anicia , Pan, Xiaowei
- Date: 2014
- Subjects: Casting simulation , Defects characterization , Quality improvement , Yield improvement
- Type: Article
- Identifier: uj:4730 , http://hdl.handle.net/10210/11556
- Description: Poor quality and low yield are major challenges to the South African foundry industry. An inspection of the process routes was conducted, and the defects occurring within the blades were investigated and characterized according to the type, size, shape and location on the castings. The presence of shrinkage porosity, gas entrapment and inclusions in the austenitic manganese scraper blades are a major concern as they result in high rejection rate, additional melting of metal and increased labour energy. This study seeks to optimize the casting process of the blades using casting simulation to visualize the filling and solidification processes of the molten metal inside the mould cavity. This will give a clear indication of the resultant casting, allowing for modification of the process in the design stages and determination of the castability. The trial and error methods will be eliminated thereby reducing operating costs and improving the overall yield.
- Full Text:
- Authors: Dipale, Anicia , Pan, Xiaowei
- Date: 2014
- Subjects: Casting simulation , Defects characterization , Quality improvement , Yield improvement
- Type: Article
- Identifier: uj:4730 , http://hdl.handle.net/10210/11556
- Description: Poor quality and low yield are major challenges to the South African foundry industry. An inspection of the process routes was conducted, and the defects occurring within the blades were investigated and characterized according to the type, size, shape and location on the castings. The presence of shrinkage porosity, gas entrapment and inclusions in the austenitic manganese scraper blades are a major concern as they result in high rejection rate, additional melting of metal and increased labour energy. This study seeks to optimize the casting process of the blades using casting simulation to visualize the filling and solidification processes of the molten metal inside the mould cavity. This will give a clear indication of the resultant casting, allowing for modification of the process in the design stages and determination of the castability. The trial and error methods will be eliminated thereby reducing operating costs and improving the overall yield.
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Chrome ores on ferrochrome smelting
- Authors: Pan, Xiaowei
- Date: 2014
- Subjects: Ferrochrome production , Ferroalloy process optimization , Chrome ores
- Type: Article
- Identifier: uj:4780 , http://hdl.handle.net/10210/11963
- Description: Chrome ores from six locations across the Bushveld Igneous Complex in South Africa are used to investigate the effects of ore types on the smelting processes, such as the consumption of fluxes, reductant; and most importantly, the consumption of electricity. The electric energy consumption is highly related to the SiO2 content of chrome ores. The lowest electric consumption of 3.31 MWh/t is required when the SiO2% of chrome ores is 6%. Considering the fact that the other contents do not change much in the selected 6 lumpy ores, an increase of SiO2 will decrease the contents of Cr and Fe oxides in the ores. As a result, it requires more ore and less quartzite to feed in the furnace. With the combined effect of more ores and less quartzite, the smelting process produces more slag and requires more electric energy to heat and melt the slag.
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- Authors: Pan, Xiaowei
- Date: 2014
- Subjects: Ferrochrome production , Ferroalloy process optimization , Chrome ores
- Type: Article
- Identifier: uj:4780 , http://hdl.handle.net/10210/11963
- Description: Chrome ores from six locations across the Bushveld Igneous Complex in South Africa are used to investigate the effects of ore types on the smelting processes, such as the consumption of fluxes, reductant; and most importantly, the consumption of electricity. The electric energy consumption is highly related to the SiO2 content of chrome ores. The lowest electric consumption of 3.31 MWh/t is required when the SiO2% of chrome ores is 6%. Considering the fact that the other contents do not change much in the selected 6 lumpy ores, an increase of SiO2 will decrease the contents of Cr and Fe oxides in the ores. As a result, it requires more ore and less quartzite to feed in the furnace. With the combined effect of more ores and less quartzite, the smelting process produces more slag and requires more electric energy to heat and melt the slag.
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Online smart sensor to measure stockpiles used in mineral processing
- Authors: Pan, Xiaowei
- Date: 2015-07-14
- Subjects: Stockpiles - Measurement , Smart sensors , Soft sensors
- Type: Article
- Identifier: uj:5160 , http://hdl.handle.net/10210/14307
- Description: With the advancement and the wide usage of measurement instruments associated with stockpiles, such as weightometers, a smart sensor can be developed to online monitor the level of a stockpile. Furthermore, the stockpile smart sensor can be used to determine the mixing behaviour of different ores discharged out of the stockpile, by combining the smart sensor technique and element modelling. The mixing behaviour of different materials includes when and how the mixing takes place, and more important, when the mixed materials with a certain portion is discharged out of the stockpile. In this article, only the level function of the stockpile smart sensor will be discussed in detail. The stockpile smart sensor can help estimate accurate residual time for different group of ores charged to the stockpile. The smart sensor makes it possible to monitor the behaviour of different ore types in real time in a stockpile, including when and how the different ores are mixed in the stockpile and when the mixed ores are discharged with certain mixing portion. Using the smart sensor system, the information on ore types can be provided for ores that are discharged from the stockpile. The ore type information includes ore grade, density, hardness, strength, etc. The stockpile smart sensor, developed originally for a diamond mine, can be used for stockpiles of other mines, including iron ore mines, coal mines, copper mines, chromium ore mine, and cement plants.
- Full Text:
- Authors: Pan, Xiaowei
- Date: 2015-07-14
- Subjects: Stockpiles - Measurement , Smart sensors , Soft sensors
- Type: Article
- Identifier: uj:5160 , http://hdl.handle.net/10210/14307
- Description: With the advancement and the wide usage of measurement instruments associated with stockpiles, such as weightometers, a smart sensor can be developed to online monitor the level of a stockpile. Furthermore, the stockpile smart sensor can be used to determine the mixing behaviour of different ores discharged out of the stockpile, by combining the smart sensor technique and element modelling. The mixing behaviour of different materials includes when and how the mixing takes place, and more important, when the mixed materials with a certain portion is discharged out of the stockpile. In this article, only the level function of the stockpile smart sensor will be discussed in detail. The stockpile smart sensor can help estimate accurate residual time for different group of ores charged to the stockpile. The smart sensor makes it possible to monitor the behaviour of different ore types in real time in a stockpile, including when and how the different ores are mixed in the stockpile and when the mixed ores are discharged with certain mixing portion. Using the smart sensor system, the information on ore types can be provided for ores that are discharged from the stockpile. The ore type information includes ore grade, density, hardness, strength, etc. The stockpile smart sensor, developed originally for a diamond mine, can be used for stockpiles of other mines, including iron ore mines, coal mines, copper mines, chromium ore mine, and cement plants.
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Increased energy efficiency of a steel foundry plant by using a cleaner production Quick-E-Scan methodology
- Rasmenia, Zelda, Pan, Xiaowei
- Authors: Rasmenia, Zelda , Pan, Xiaowei
- Date: 2017
- Subjects: Energy efficiency , Energy assessment , Quick-E-scan methodology
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239156 , uj:24566 , Citation: Rasmenia, Z. & Pan, X. 2017. Increased energy efficiency of a steel foundry plant by using a cleaner production Quick-E-Scan methodology.
- Description: Abstract: The Quick-E-Scan methodology is a simple and quick method that is used to achieve operational energy efficiency as opposed to detailed energy audits, which therefore offers a no cost or less cost solutions for energy management programs with a limited budget. The quick-E-scan methodology was used to assesses a steel foundry plant based in Benoni through dividing the foundry into production sections which entailed a review of the current processes and usage patterns of energy within the plant and a detailed analysis of options available for improvement and profitable areas in which energy saving measures may be implemented for an increase energy efficiency which can be presented to management of the company.
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- Authors: Rasmenia, Zelda , Pan, Xiaowei
- Date: 2017
- Subjects: Energy efficiency , Energy assessment , Quick-E-scan methodology
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239156 , uj:24566 , Citation: Rasmenia, Z. & Pan, X. 2017. Increased energy efficiency of a steel foundry plant by using a cleaner production Quick-E-Scan methodology.
- Description: Abstract: The Quick-E-Scan methodology is a simple and quick method that is used to achieve operational energy efficiency as opposed to detailed energy audits, which therefore offers a no cost or less cost solutions for energy management programs with a limited budget. The quick-E-scan methodology was used to assesses a steel foundry plant based in Benoni through dividing the foundry into production sections which entailed a review of the current processes and usage patterns of energy within the plant and a detailed analysis of options available for improvement and profitable areas in which energy saving measures may be implemented for an increase energy efficiency which can be presented to management of the company.
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Improvement of wear property of carbon steel by vanadium carbide surface layer
- Authors: Pan, Xiaowei
- Date: 2014
- Subjects: Steel surface treatment , Vanadium carbide , Surface alloying
- Type: Article
- Identifier: uj:4732 , http://hdl.handle.net/10210/11558
- Description: Carbon steels are widely used in manufacturing of simple constructions and machine elements. The main limitations of these materials are their low hardness, poor friction and poor wear properties. For that reason, many attempts have been made to improve their hardness and other mechanical properties. One of the challenges is to find ways to improve the surface property of cheap steels in order to enhance its usage properties and ultimately extend the service life in an economic way. Due to its high hardness, vanadium carbides are often applied to the surface of carbon steels through coating processed and thermal diffusion processes. Samples of high carbon steels are treated using the molten slag process to form vanadium-based alloy layer on the surface of steel. After treatment using the mentioned molten slag process, the anti-wearing property of high carbon steel is improved by 15.6 times. The surface-alloy layers on high carbon steel are found in the form of vanadium carbide with a composition of VC0.8. The hardness of the alloy layer is 2200Hv, 3.4 times higher than that of high carbon steel.
- Full Text:
- Authors: Pan, Xiaowei
- Date: 2014
- Subjects: Steel surface treatment , Vanadium carbide , Surface alloying
- Type: Article
- Identifier: uj:4732 , http://hdl.handle.net/10210/11558
- Description: Carbon steels are widely used in manufacturing of simple constructions and machine elements. The main limitations of these materials are their low hardness, poor friction and poor wear properties. For that reason, many attempts have been made to improve their hardness and other mechanical properties. One of the challenges is to find ways to improve the surface property of cheap steels in order to enhance its usage properties and ultimately extend the service life in an economic way. Due to its high hardness, vanadium carbides are often applied to the surface of carbon steels through coating processed and thermal diffusion processes. Samples of high carbon steels are treated using the molten slag process to form vanadium-based alloy layer on the surface of steel. After treatment using the mentioned molten slag process, the anti-wearing property of high carbon steel is improved by 15.6 times. The surface-alloy layers on high carbon steel are found in the form of vanadium carbide with a composition of VC0.8. The hardness of the alloy layer is 2200Hv, 3.4 times higher than that of high carbon steel.
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Analysis of energy efficiency and consumption in South African steel foundries
- Authors: Rasmeni, Z.Z. , Pan, Xiaowei
- Date: 2014
- Subjects: Energy efficiency - South Africa , Steel foundries - South Africa
- Type: Article
- Identifier: uj:4779 , http://hdl.handle.net/10210/11962
- Description: Efficient energy use, sometimes simply called energy efficiency, is the goal to reduce the amount of energy required to provide products and services. Lack of efficient process skills, education and training has become a major issue in recent years regarding the up-stepping of energy efficiency in steel industries. This paper highlights the overview of the current state of energy efficiency in South African foundries, improvements made and challenges faced by the foundry industry in South Africa upon implementation of energy efficiency. In this paper we acknowledge the need for studying the current energy consumption and the improvement that has been done in order to analyse the problems of implementation. Barriers studied are: lack of capital, resistance to change, uncertainties and attitude. An active interaction between the academia and foundry industry (men) will further enhance suitable skills to move South African steel foundries in to an energy efficient industry.
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- Authors: Rasmeni, Z.Z. , Pan, Xiaowei
- Date: 2014
- Subjects: Energy efficiency - South Africa , Steel foundries - South Africa
- Type: Article
- Identifier: uj:4779 , http://hdl.handle.net/10210/11962
- Description: Efficient energy use, sometimes simply called energy efficiency, is the goal to reduce the amount of energy required to provide products and services. Lack of efficient process skills, education and training has become a major issue in recent years regarding the up-stepping of energy efficiency in steel industries. This paper highlights the overview of the current state of energy efficiency in South African foundries, improvements made and challenges faced by the foundry industry in South Africa upon implementation of energy efficiency. In this paper we acknowledge the need for studying the current energy consumption and the improvement that has been done in order to analyse the problems of implementation. Barriers studied are: lack of capital, resistance to change, uncertainties and attitude. An active interaction between the academia and foundry industry (men) will further enhance suitable skills to move South African steel foundries in to an energy efficient industry.
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Using programming to optimize mineral processing
- Authors: Pan, Xiaowei
- Date: 2015-07-14
- Subjects: Process optimization , Mineral processing , Process simulation , Ore beneficiation
- Type: Article
- Identifier: uj:5161 , http://hdl.handle.net/10210/14308
- Description: Ore beneficiation at a mine could be described as complex and expensive, involving many balancing processes where material flow rates, size, density and other factors must all be in balance, if any degree of plant optimization is to be achieved. To determine the optimum setup for maximizing throughput at the final step in the beneficiation process, such as the dense media separation units, a mine optimizer is developed to maximize the production throughput as objective function, using constraint-based global optimization. The mine optimizer uses a search engine to find a set of operational conditions, that will help achieve the maximum production within all constraints, such as the availability of plant, the capacity of all press units; the change in material size and property (between crushers) and other operational conditions at the mineral process plant. The result is that improving cheaper upstream processes, such as blasting, can significantly increase the throughput of expensive downstream processes, like crushing, through improved fragmentation of the ROM ore. For instance, if the ROM ore is not in the required range, the plant production is unbalanced and consequently the mine could loss production by 10-20%, even up to 50% of production loss in the worst case. On one hand, a finer ROM ore may result in lower production of both crushing and coarse separation by 50%, while other process units are running at 100% capacity, such as slimes and tailing dumping. In addition, a finer ROM ore! may destroy the mineral value as well, such as in the cases of mining coal, iron ore, and diamond ore, where a higher price is paid for the products of larger size.
- Full Text:
- Authors: Pan, Xiaowei
- Date: 2015-07-14
- Subjects: Process optimization , Mineral processing , Process simulation , Ore beneficiation
- Type: Article
- Identifier: uj:5161 , http://hdl.handle.net/10210/14308
- Description: Ore beneficiation at a mine could be described as complex and expensive, involving many balancing processes where material flow rates, size, density and other factors must all be in balance, if any degree of plant optimization is to be achieved. To determine the optimum setup for maximizing throughput at the final step in the beneficiation process, such as the dense media separation units, a mine optimizer is developed to maximize the production throughput as objective function, using constraint-based global optimization. The mine optimizer uses a search engine to find a set of operational conditions, that will help achieve the maximum production within all constraints, such as the availability of plant, the capacity of all press units; the change in material size and property (between crushers) and other operational conditions at the mineral process plant. The result is that improving cheaper upstream processes, such as blasting, can significantly increase the throughput of expensive downstream processes, like crushing, through improved fragmentation of the ROM ore. For instance, if the ROM ore is not in the required range, the plant production is unbalanced and consequently the mine could loss production by 10-20%, even up to 50% of production loss in the worst case. On one hand, a finer ROM ore may result in lower production of both crushing and coarse separation by 50%, while other process units are running at 100% capacity, such as slimes and tailing dumping. In addition, a finer ROM ore! may destroy the mineral value as well, such as in the cases of mining coal, iron ore, and diamond ore, where a higher price is paid for the products of larger size.
- Full Text:
An overview on high manganese steel casting
- Authors: Mahlami, C.S. , Pan, Xiaowei
- Date: 2014
- Subjects: Melting temperature , Work hardening rate , Austenitic manganese steel
- Type: Article
- Identifier: uj:4731 , ISSN 978-84-617-0087-5 , http://hdl.handle.net/10210/11557
- Description: Hadfield steel invented in 1882 has an enormous capacity for work-hardening upon impact and it is commonly used for railroad components such as frogs and crossings and for rock-handling equipment. It has nominal composition of iron, 1.0 to 1.4 % carbon and 10 to 14% manganese in a 1 to 10 ratio. The present paper deals with a comprehensive analysis on the overview of high manganese steel casting. The effect of chemical composition was analysed highlighting how different alloying element can affect the final mechanical properties of high manganese steel casting. Good and bad practices were reviewed, looking at how high melting temperature can course micro and macro segregation at the grain boundaries resulting in uneven wear rate and loss of strength and impact of the said steel. A Proper heat treatment cycle was discussed and typical mechanical properties and work hardening rate of the steel was also emphasised on, so as to know on which application is the steel best suited for.
- Full Text:
- Authors: Mahlami, C.S. , Pan, Xiaowei
- Date: 2014
- Subjects: Melting temperature , Work hardening rate , Austenitic manganese steel
- Type: Article
- Identifier: uj:4731 , ISSN 978-84-617-0087-5 , http://hdl.handle.net/10210/11557
- Description: Hadfield steel invented in 1882 has an enormous capacity for work-hardening upon impact and it is commonly used for railroad components such as frogs and crossings and for rock-handling equipment. It has nominal composition of iron, 1.0 to 1.4 % carbon and 10 to 14% manganese in a 1 to 10 ratio. The present paper deals with a comprehensive analysis on the overview of high manganese steel casting. The effect of chemical composition was analysed highlighting how different alloying element can affect the final mechanical properties of high manganese steel casting. Good and bad practices were reviewed, looking at how high melting temperature can course micro and macro segregation at the grain boundaries resulting in uneven wear rate and loss of strength and impact of the said steel. A Proper heat treatment cycle was discussed and typical mechanical properties and work hardening rate of the steel was also emphasised on, so as to know on which application is the steel best suited for.
- Full Text:
Manganese alloys production : impact of chemical compositions of raw materials on the energy and materials balance
- Wa Kalenga, Michel M.K., Pan, Xiaowei, Tangstad, M.
- Authors: Wa Kalenga, Michel M.K. , Pan, Xiaowei , Tangstad, M.
- Date: 2014
- Subjects: Manganese alloys , Ferromanganese alloys
- Type: Article
- Identifier: uj:4941 , http://hdl.handle.net/10210/13041
- Description: Refer to abstract in full-text
- Full Text: false
- Authors: Wa Kalenga, Michel M.K. , Pan, Xiaowei , Tangstad, M.
- Date: 2014
- Subjects: Manganese alloys , Ferromanganese alloys
- Type: Article
- Identifier: uj:4941 , http://hdl.handle.net/10210/13041
- Description: Refer to abstract in full-text
- Full Text: false
The effect of GHG emission on climate change due to inefficient usage of energy in South African steel foundries
- Authors: Rasmeni, Z.Z. , Pan, Xiaowei
- Date: 2014
- Subjects: Electricity generation , Greenhouse gas emissions , Climate change - South Africa , Energy efficiency - South Africa , Renewable energy sources
- Type: Article
- Identifier: uj:4778 , http://hdl.handle.net/10210/11961
- Description: Mitigation of CO2 emission is the Lessing of CO2 produced that have or could have a serious threat on climate change. South Africa is known to have a coal addiction. This paper attempts to identify the major opportunities for climate change mitigation through foundry energy efficiency. It does so by analysing key areas of carbon and energy efficiency policy in South Africa. The report further considers a number of important areas concerning future carbon and energy efficiency policy development in the country. Electricity generation and renewable energies are clearly discussed with their advantages and dis advantages in the operation of foundry industry; furthermore it highlights the effect of burning of coal on climate change raising regulation such as carbon tax to be proposed to reduce the growth of CO2 emission. Mitigation of CO2 through foundries by using best energy efficiency practices is highlighted as part of assisting in fighting excessive CO2 emission.
- Full Text:
- Authors: Rasmeni, Z.Z. , Pan, Xiaowei
- Date: 2014
- Subjects: Electricity generation , Greenhouse gas emissions , Climate change - South Africa , Energy efficiency - South Africa , Renewable energy sources
- Type: Article
- Identifier: uj:4778 , http://hdl.handle.net/10210/11961
- Description: Mitigation of CO2 emission is the Lessing of CO2 produced that have or could have a serious threat on climate change. South Africa is known to have a coal addiction. This paper attempts to identify the major opportunities for climate change mitigation through foundry energy efficiency. It does so by analysing key areas of carbon and energy efficiency policy in South Africa. The report further considers a number of important areas concerning future carbon and energy efficiency policy development in the country. Electricity generation and renewable energies are clearly discussed with their advantages and dis advantages in the operation of foundry industry; furthermore it highlights the effect of burning of coal on climate change raising regulation such as carbon tax to be proposed to reduce the growth of CO2 emission. Mitigation of CO2 through foundries by using best energy efficiency practices is highlighted as part of assisting in fighting excessive CO2 emission.
- Full Text:
Effect of South Africa Reductants on Ferrochrome Production
- Authors: Pan, Xiaowei
- Subjects: Ferrochrome production , Process simulation , South African reductant
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/15318 , uj:15645
- Description: With a limited supply of electricity, and sharp increase of electricity tariffs, South Africa’s share of world ferrochrome production has declined to 38% in 2011. The situation is set to continue and could go from bad to worse in the near future.Consequently, all ferrochrome producers in South Africa are looking for any alternatives that can use less electricity. An investigation of the effect of various reductants on the electric energy consumption is under consideration. A group of reductants, consisting of 6 types of coke and 2 types of anthracite, is selected to investigate the effect on energy consumption of ferrochrome production in submerged arc furnace. An excel-based simulation is used to calculate all charges and energy usage with similar production conditions used by most ferrochrome producers in South Africa.
- Full Text: false
- Authors: Pan, Xiaowei
- Subjects: Ferrochrome production , Process simulation , South African reductant
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/15318 , uj:15645
- Description: With a limited supply of electricity, and sharp increase of electricity tariffs, South Africa’s share of world ferrochrome production has declined to 38% in 2011. The situation is set to continue and could go from bad to worse in the near future.Consequently, all ferrochrome producers in South Africa are looking for any alternatives that can use less electricity. An investigation of the effect of various reductants on the electric energy consumption is under consideration. A group of reductants, consisting of 6 types of coke and 2 types of anthracite, is selected to investigate the effect on energy consumption of ferrochrome production in submerged arc furnace. An excel-based simulation is used to calculate all charges and energy usage with similar production conditions used by most ferrochrome producers in South Africa.
- Full Text: false
Importance and effect of foaming slag on energy efficiency
- Authors: Kipepe, T.M. , Pan, Xiaowei
- Date: 2014
- Subjects: Foaming slag , Energy efficiency , Heat loss , Electrical energy consumption
- Type: Article
- Identifier: uj:4760 , ISSN 978-84-617-0087-5 , http://hdl.handle.net/10210/11763
- Description: The present paper is an overview of the benefit of the foaming slag being used as major elements in the energy efficiency campaign. The aim of this work is to show and demonstrate the importance of using a foaming slag in the furnaces to reduce energy consumption, the heat loss or either to decrease the melting time during the process. Different methodologies have been used according to authors. Some have used injected gases to enhance the creation of the foam, other have added some carbon particles contents which creates a chemical reaction by forming bubbles as a foam and insulator layer. Impressive results have been found and real changes have been made. The results have contributed to different purpose such as: decreasing the global warming by controlling the retaining heat, decreasing the noise and vibration in furnace and finally decrease the use of the electrical energy consumption.
- Full Text:
- Authors: Kipepe, T.M. , Pan, Xiaowei
- Date: 2014
- Subjects: Foaming slag , Energy efficiency , Heat loss , Electrical energy consumption
- Type: Article
- Identifier: uj:4760 , ISSN 978-84-617-0087-5 , http://hdl.handle.net/10210/11763
- Description: The present paper is an overview of the benefit of the foaming slag being used as major elements in the energy efficiency campaign. The aim of this work is to show and demonstrate the importance of using a foaming slag in the furnaces to reduce energy consumption, the heat loss or either to decrease the melting time during the process. Different methodologies have been used according to authors. Some have used injected gases to enhance the creation of the foam, other have added some carbon particles contents which creates a chemical reaction by forming bubbles as a foam and insulator layer. Impressive results have been found and real changes have been made. The results have contributed to different purpose such as: decreasing the global warming by controlling the retaining heat, decreasing the noise and vibration in furnace and finally decrease the use of the electrical energy consumption.
- Full Text:
An overview on types of white cast irons and high chromium white cast irons
- Ngqase, Mbulelo, Pan, Xiaowei
- Authors: Ngqase, Mbulelo , Pan, Xiaowei
- Date: 2020
- Subjects: white cast irons , High chromium white cast irons
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/453537 , uj:40044 , Citation: Mbulelo Ngqase and Xiaowei Pan 2020 J. Phys.: Conf. Ser. 1495 012023 , DOI:10.1088/1742-6596/1495/1/012023
- Description: Abstract: Crushing and grinding are widely used in mining, mineral processing, cement making, and coal power generation. The mechanical components that contact with materials being processed are working under the conditions of high abrasion and impact. How to reduce the wearing damages and prevent from the cracking failure of the mechanical parts is one of the crucial challenges facing the operations of many industries, involved crushing and grinding processes. Whit cast irons, and specifically high chromium white cast irons, have been developed and deployed worldwide for making mechanical components of crushing and grinding machines due to the combination of high wear resistance and good mechanical strength. The paper is aimed to give an overview on the white cast iron alloys, and particularly high chromium white cast iron alloys, including their classifications, their standard specifications in USA, China and Australia, their main usages and the new developments.
- Full Text:
- Authors: Ngqase, Mbulelo , Pan, Xiaowei
- Date: 2020
- Subjects: white cast irons , High chromium white cast irons
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/453537 , uj:40044 , Citation: Mbulelo Ngqase and Xiaowei Pan 2020 J. Phys.: Conf. Ser. 1495 012023 , DOI:10.1088/1742-6596/1495/1/012023
- Description: Abstract: Crushing and grinding are widely used in mining, mineral processing, cement making, and coal power generation. The mechanical components that contact with materials being processed are working under the conditions of high abrasion and impact. How to reduce the wearing damages and prevent from the cracking failure of the mechanical parts is one of the crucial challenges facing the operations of many industries, involved crushing and grinding processes. Whit cast irons, and specifically high chromium white cast irons, have been developed and deployed worldwide for making mechanical components of crushing and grinding machines due to the combination of high wear resistance and good mechanical strength. The paper is aimed to give an overview on the white cast iron alloys, and particularly high chromium white cast iron alloys, including their classifications, their standard specifications in USA, China and Australia, their main usages and the new developments.
- Full Text:
Microstructural investigation on heat treatment of hypoeutectic high chromium white cast irons
- Ngqase, Mbulelo, Pan, Xiaowei
- Authors: Ngqase, Mbulelo , Pan, Xiaowei
- Date: 2020
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/451916 , uj:39844 , DOI:10.1088/1742-6596/1495/1/012024 , Citation: bulelo Ngqase and Xiaowei Pan 2020 J. Phys.: Conf. Ser. 1495 012024
- Description: Abstract: High chromium white cast irons (HCWCI) are widely used as abrasion resistant materials in cement manufacturing, mineral processing and slurry pumping industries. Their high resistance to wear in these demanding situations stems from the presence of hard eutectic (Cr,Fe)7C3 carbides in their microstructures. In this context, the properties of hypoeutectic iron of HCWCI containing 25 wt. %Cr-2.5 wt. %C were investigated after destabilisation heat treatments, cooling (slow and fast cooling) to ambient temperatures, their influence on the microstructure was investigated. For characterization of the hypoeutectic iron of HCWCI, several experimental tests were performed using the following laboratory equipment: light optical microscope, scanning electron microscope. The amount of retained austenite also depends on the alloying additions in the melt during melting processes, destabilisation temperatures, soaking time and the cooling rates during heat treatment processes.
- Full Text:
- Authors: Ngqase, Mbulelo , Pan, Xiaowei
- Date: 2020
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/451916 , uj:39844 , DOI:10.1088/1742-6596/1495/1/012024 , Citation: bulelo Ngqase and Xiaowei Pan 2020 J. Phys.: Conf. Ser. 1495 012024
- Description: Abstract: High chromium white cast irons (HCWCI) are widely used as abrasion resistant materials in cement manufacturing, mineral processing and slurry pumping industries. Their high resistance to wear in these demanding situations stems from the presence of hard eutectic (Cr,Fe)7C3 carbides in their microstructures. In this context, the properties of hypoeutectic iron of HCWCI containing 25 wt. %Cr-2.5 wt. %C were investigated after destabilisation heat treatments, cooling (slow and fast cooling) to ambient temperatures, their influence on the microstructure was investigated. For characterization of the hypoeutectic iron of HCWCI, several experimental tests were performed using the following laboratory equipment: light optical microscope, scanning electron microscope. The amount of retained austenite also depends on the alloying additions in the melt during melting processes, destabilisation temperatures, soaking time and the cooling rates during heat treatment processes.
- Full Text:
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