Evaluation of a platinum group metal flotation re-cleaner stage performance and possible improvement
- Nheta, Willie, Mphahlele, Karabo
- Authors: Nheta, Willie , Mphahlele, Karabo
- Date: 2019
- Subjects: Platinum-group mineral , Flotation , Chromite
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/400038 , uj:33368 , Citation: Nheta, W. & Mphahlele, K. 2019. Evaluation of a platinum group metal flotation re-cleaner stage performance and possible improvement.
- Description: Abstract: South Africa has massive Platinum Group Metal (PGM) deposits found in Bushveld Igneous Complex (BIC). Due to depletion of Merensky reef, many companies are now treating UG2 reef which has a high chromite content which has negative impact in the smelting process of the platinum concentrates. Generally, PGMs are processed by rougher followed by cleaner and re-cleaner flotation banks and the final concentrate must contain less than 3% chromite. The effect of residence time and depressant dosage on PGM recovery and chromite entrainment on the recleaner stage was investigated by floating the feed to the re-cleaner banks using Dow froth 200, Cu2SO4, sodium isobutyl xanthate and carboxymethyl cellulose in a 3l Denver cell. It was found that extra 30g/t of depressant dosage (carboxymethyl cellulose) from standard conditions reduces the chromite content to 2.11% from 8.63% and only 37.54% of PGMs are lost to the recleaner tailings which are recirculated to the cleaner feed. The residence time was reduced by 15minutes from the normal residence time. The Malvern particle size analyzer results indicated that the increase in depressant dosage and decrease in residence time the finer the concentrate. By controlling the depressant dosage, amount of chromite content in the final concentrate can effectively be reduced to meet the required standards.
- Full Text:
Evaluation of a platinum group metal flotation re-cleaner stage performance and possible improvement
- Authors: Nheta, Willie , Mphahlele, Karabo
- Date: 2019
- Subjects: Platinum-group mineral , Flotation , Chromite
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/400038 , uj:33368 , Citation: Nheta, W. & Mphahlele, K. 2019. Evaluation of a platinum group metal flotation re-cleaner stage performance and possible improvement.
- Description: Abstract: South Africa has massive Platinum Group Metal (PGM) deposits found in Bushveld Igneous Complex (BIC). Due to depletion of Merensky reef, many companies are now treating UG2 reef which has a high chromite content which has negative impact in the smelting process of the platinum concentrates. Generally, PGMs are processed by rougher followed by cleaner and re-cleaner flotation banks and the final concentrate must contain less than 3% chromite. The effect of residence time and depressant dosage on PGM recovery and chromite entrainment on the recleaner stage was investigated by floating the feed to the re-cleaner banks using Dow froth 200, Cu2SO4, sodium isobutyl xanthate and carboxymethyl cellulose in a 3l Denver cell. It was found that extra 30g/t of depressant dosage (carboxymethyl cellulose) from standard conditions reduces the chromite content to 2.11% from 8.63% and only 37.54% of PGMs are lost to the recleaner tailings which are recirculated to the cleaner feed. The residence time was reduced by 15minutes from the normal residence time. The Malvern particle size analyzer results indicated that the increase in depressant dosage and decrease in residence time the finer the concentrate. By controlling the depressant dosage, amount of chromite content in the final concentrate can effectively be reduced to meet the required standards.
- Full Text:
Liberation analysis of South African middle group seam chromite ore processed with vertical shaft impactor crusher
- Maruli, Mashudu, Nheta, Wille
- Authors: Maruli, Mashudu , Nheta, Wille
- Date: 2020
- Subjects: Chromite , Middle Group seam , Liberation
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/450662 , uj:39622 , Citation: Maruli, M. & Nheta, W. 2020. Liberation analysis of South African middle group seam chromite ore processed with vertical shaft impactor crusher.
- Description: Abstract: In this study, the impact of vertical shaft impactor (VSI) crusher on fine and ultrafine production during crushing of South African Middle group (MG) chromite seam was investigated. The chromite ore was subjected to size reduction with VSI crusher at varied rotor tip speed (30, 35 &40 Hz) and particle size distribution analysis was done on all the three products. The VSI crusher product particle size distribution indicated that as the VSI rotor speed was increased, the amount of ultrafine generated also increased. The product at rotor speed of 35Hz revealed a lower percentage of ultrafines at 6.16% in the -212+150μm and 0.85% in the -150+53μm particle size range. Ball mill product from the Plant was analysed and the results revealed that the ball mill is more efficient for chromite ore liberation as 84% of the -425+300μm was produced compared to the VSI which only produced 51.27% -425+300μm. However, the amount of ultrafines produced was high at 9.2% of -150+106μm size fraction, with most ultrafine particle size of 4.42% in the -53+26μm size fraction. The mineral liberation analysis conducted on the -425+300 and -300+212μm VSI crusher products indicated that the degree of chromite liberation was higher at 95% on the -300+212μm size fraction compared to 78% liberation on the -425+300 μm size fraction. From the liberation analysis conducted in this investigation, it can be concluded that VSI crusher has a greater potential in chromite size reduction as it has shown to produce a liberated product with reduced percentage of ultrafines. However more test needs to be done on the VSI residence time to improve the percentage mass of the required liberated product particle size.
- Full Text:
- Authors: Maruli, Mashudu , Nheta, Wille
- Date: 2020
- Subjects: Chromite , Middle Group seam , Liberation
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/450662 , uj:39622 , Citation: Maruli, M. & Nheta, W. 2020. Liberation analysis of South African middle group seam chromite ore processed with vertical shaft impactor crusher.
- Description: Abstract: In this study, the impact of vertical shaft impactor (VSI) crusher on fine and ultrafine production during crushing of South African Middle group (MG) chromite seam was investigated. The chromite ore was subjected to size reduction with VSI crusher at varied rotor tip speed (30, 35 &40 Hz) and particle size distribution analysis was done on all the three products. The VSI crusher product particle size distribution indicated that as the VSI rotor speed was increased, the amount of ultrafine generated also increased. The product at rotor speed of 35Hz revealed a lower percentage of ultrafines at 6.16% in the -212+150μm and 0.85% in the -150+53μm particle size range. Ball mill product from the Plant was analysed and the results revealed that the ball mill is more efficient for chromite ore liberation as 84% of the -425+300μm was produced compared to the VSI which only produced 51.27% -425+300μm. However, the amount of ultrafines produced was high at 9.2% of -150+106μm size fraction, with most ultrafine particle size of 4.42% in the -53+26μm size fraction. The mineral liberation analysis conducted on the -425+300 and -300+212μm VSI crusher products indicated that the degree of chromite liberation was higher at 95% on the -300+212μm size fraction compared to 78% liberation on the -425+300 μm size fraction. From the liberation analysis conducted in this investigation, it can be concluded that VSI crusher has a greater potential in chromite size reduction as it has shown to produce a liberated product with reduced percentage of ultrafines. However more test needs to be done on the VSI residence time to improve the percentage mass of the required liberated product particle size.
- Full Text:
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