Abstract
Climate is changing at a rapid pace due to an increase in greenhouse gas emissions resulting
from industrial processes. The processing of feedstock such as limestone in rotary kilns fired
with pulverised coal in the cement industry makes the manufacturing process contribute to
greenhouse gases emissions by the release of carbon dioxide. Globally, the industrial sector
contributes a significant share of GHG emissions; this is seen as the direct contribution of GHG
emission year 1990 to 2014, the emissions increased by about 70 per cent or 2.2 per annum on
average. The United Nations’ sustainable development agenda targets sustainable development
goals with an objective to ascertain patterns of sustainable production and consumption, and to
act quickly to counter global warming and its effects. South Africa is categorised as one of the
economies that have high carbon dioxide emissions worldwide. Carbon dioxide is one of
greenhouse gases associated with change in climate. Climate change is an environmental
concern globally which has impact on human (Woolard, 2015). It is associated with variations
in patterns of weather which entail melting of polar and glacier ice, rise in sea level,
acidification of ocean, variation in rainfall and patterns of snowfall, frequent floods and
droughts, rise in events of weather more frequently and intensively, that are extreme such as
tornadoes, hurricanes and cyclones (South African Government, 2014). South Africa continues
to experience extreme weather patterns that are attributed to the observed variations in the
climate system. Furthermore, it is also noted that the country is warming at 0.16 °C rate every
decade which is 5% level of statistical significance.
The cement manufacturing process is pertaining to the release of 0.87 tonnes carbon dioxide
during the production of 1 tonne Ordinary Portland Cement. Globally, Portland cement
manufacturers are pressed with environmental compliance for the minimization of emissions
of greenhouse gasses from industrial operations. Management of sustainable operations is of
great need for achievement of the Net Zero Carbon emissions transition by year 2050.
Specifically, carbon dioxide is amongst the gases released from cement plant operations which
needs to be managed for environmental compliance. This research has centred on the
development of an integrated framework for decarbonisation in a cement manufacturing plant
of South Africa. The specific objectives that guided the study were to: (i) investigate raw
material alterations on cement product formulation on the reduction of carbon dioxide cement
plant process improvement, (ii) evaluate the manufacturing operations re-engineering and
equipment upgrade for the reduction of carbon dioxide emissions for cement plant process
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improvement, (iii) investigate the South African government's Carbon Tax policy’s capability
in reducing emissions, (iv) investigate the impact of digitalisation on carbon dioxide emissions
reduction for cement plant process improvement, and (v) design an operations framework for
the reduction of carbon dioxide emissions for cement plant process improvement. The reviewed
literature have identified possible options to decarbonise the cement manufacturing process,
however, in a manner that does not strongly suggest the combination of these available
individual decarbonisation strategies to yield an overall framework to reduce carbon dioxide
in a cement manufacturing plant such in South Africa. Thus, the study aims to contribute to the
body of knowledge through the creation of solutions that can be tested and implemented to
reduce carbon dioxide emissions within the Portland cement manufacturing industry in South
Africa. This further assist Portland cement manufacturers to strive to meet the requirements of
the Net Zero Carbon Emissions Transition. The research also help slow down the rate of global
warming caused by greenhouse gas emissions. To achieve the objective of the study, qualitative
and quantitative approach were combined to generate a mixed method research design through
collection of data at the participants within the cement manufacturing operations. Collection of
qualitative data was through structured interviews, while quantitative data was through
questionnaire on Likert scale. A census was used as sample for the study. Computer software
namely: Statistical Package for the Social Sciences (SPSS) and ATLAS.ti were used for
quantitative and qualitative statistical data analysis, respectively. Reliability analysis, factor
analysis, descriptive analysis, frequency analysis, correlation analysis, regression analysis,
hypothesis analysis, content analysis, thematic analysis, pattern analysis and sentiment analysis
were conducted. The demographic profiles of the total participants indicated that 23%, 23%,
15%, 15%, 4%, 8%, and 11% of respondents worked at the Cement mills, Kilns, Quality
control, Packaging, Production, Plant Management, and Commercial section of the plant.
Meanwhile, their educational background were 17%, 32%, 17%, 21%, 11%, and 2% of the
respondents having a Matric, National Diploma, Advanced Diploma, Postgraduate Diploma,
Master’s Degree, and PhD as their highest qualification level. The key highlights of the
quantitative data analysis were that, using reliability statistics, the Cronbach’s Alpha test
depicted that the alpha coefficient equals 98.6% which is superior to the 70% threshold. This
suggests that the Decarbonisation for cement plant process improvement is relevantly
determined by cement manufacturing process, manufacturing operations re-engineering,
carbon tax policy, and digitalisation of the cement manufacturing process. The exploratory
factor analysis is adequate because the Kaiser-Meyer-Olkin Measure of Sampling Adequacy is
0.869, more than 0.60. This result is supported by a significant Bartlett’s test of sphericity with
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a p-value less than 1%. Descriptive statistics observed on the research variables which includes
the mean, median, range variance, and standard deviation. It also reflected the skewness and
Kurtosis that were used for the normality test in the frequency analysis using histograms. In
comparison with the standard deviation, the mean indicates that once the cement manufacturing
process, manufacturing operations re-engineering, carbon tax policy, and digitalisation of the
cement manufacturing process are observed, the probability of achieving Decarbonisation for
the cement plant process improvement is quite high. The correlation analysis indicated that
there is a strong and positive relationship with the correlation coefficient of 91.8%, 91.8%,
91.5%, and 93.2% between the Cement manufacturing process, and the Manufacturing
operations re-engineering, Carbon tax policy, Digitalisation of the cement manufacturing
process, and the Decarbonisation for cement plant process improvement respectively. The
content analysis indicated that the need for greenhouse gas emission reduction during cement
manufacturing was associated with some factors such as reduction in clinker usage, removal of
carbon from the atmosphere, adoption of cleaner technologies, a need for alternative fuels and
comply with regulations. The production of CEM I/52.5R cement existed in the plant in
addition to other cement types produced using fly ash, limestone and slag such as CEM IV/B
and CEM V/A. Carbon tax is viewed as driving the production of green cement which entailed
putting a price on carbon emissions as striving for greener products is not always cheap. There
should be some incentives to reduce carbon footprint with technologies supported by the
government. The alternative fuels used during kiln firing as an initiative to reduce carbon
dioxide emission included fuels with higher biomass content for use in kiln and pre-calcination
processes. Other alternative raw material used includes tires, waste oil sludge, industrial waste
and coal fines. Furthermore, the importance of supplementary cementitious materials in South
Africa were perceived to be relevant to some of factors such as reduced clinker factor with fly
ash being powerful for reduction based on its availability and cost effectivity. However, loadshedding
as a risk to fly ash availability in green cement production, meanwhile, the steel
industry reduction in demand also poses a risk of slag availability. The cement manufacturing
plant can also be modified and retrofitted with carbon dioxide emission reduction technologies
for continuous improvement initiatives. These include Waste Heat Recovery systems,
optimisation of kiln operations, grinding efficiencies, carbon capture and storage technologies.
Digitisation technologies can be deployed to reduce carbon dioxide emission such as SCADA
production software, feeding adjusting parameters for reduction coal usage based on pattern
analysis, and real time sensors for management of energy and emissions efficiencies. Thus,
these findings indicated that the theoretical integrated framework for decarbonisation in a
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cement plant of South Africa was associated with integration of strategies within raw material
and cement product formulation, manufacturing operations re-engineering, carbon tax policy
and digitalisation.