Life cycle assessment of steel balls

Abstract: Global warming effects have become very apparent in many parts of the world causing governments to force their industries to be environmentally conscious. Small individual contributions will help abate global warming. The steel industry, if left unattended, has great potential of releasing greenhouse gases into the atmosphere. In this paper a life cycle assessment (LCA) for steel balls used as grinding media in mines that are produced at Craster International in Zimbabwe is discussed. Knowing the life cycle environmental impacts of the steel balls is very important since they produce greenhouse gases in their production. The emitted carbon dioxide, sulphur dioxide, nitrous oxides and other trace greenhouse gases have adverse effects on flora, fauna, water bodies and humans. Interviews, questionnaire and direct observation and measurements were used to generate the data. The data is analyzed and a new LCA diagram from the results of the research and recommendations was made

Designing a quenching system for grinding steel balls - case study

Abstract: The availability of grinding balls of superior quality than those produced at a Harare company in Zimbabwe, resulted in loss of business. In order to retain business, a new ball that has a similar chemical composition to that of imported grinding balls was developed. Proper thermo-mechanical treatment has to be done after casting, in order for the ball to be of satisfactory quality. In this research, heat treatment tests were done on the developed ball to determine a suitable quenching medium for the heat treatment cycle. Using the results of the heat treatment tests obtained, a suitable heat treatment cycle which utilises optimum quenching medium and has effective agitation for minimal defects was designed

Design of a ferrochrome – slag mechanical separator : case study

Abstract: This research focused on the design of a ferrochrome – slag mechanical separator for a company in Harare, Zimbabwe. The company’s current production is 420 tonnes of alloy per month. The aim of project is to raise the production from 420 to 500 tonnes of ferrochrome production per month by introducing a mechanical separator at metal recovery plant that produces 80 tonnes. The difference in specific gravities of ferrochrome and slag is the key principle applied in achieving separation of the two products. The densities of ferrochrome and slag are 6800 kg/ mand 2800kg/ m respectively hence gravity separation method in water medium can be done

Industrial sustainability in a challenged economy : the Zimbabwe steel industry

Abstract: The economy of Zimbabwe has deteriorated over the years with hyperinflation. In the years 2006 to 2008 the conditions worsened and in 2009 a multicurrency system including the US dollar was introduced, however investment in the industry did not strengthen and a number of challenges are still faced by the industry. A main feature of the Industry in Zimbabwe had been the steel and steel related manufacturing industry which was key for both domestic and foreign markets. The motivation for this study was to investigate and propose st rategies for enhancing sustainability of steel making companies in Zimbabwe. The aim of this research was to undertake a requirements analysis from the steel companies and identify the main challenges from the point of view of steel production. From these challenges the paper aimed to help codefine some of the possible solutions the companies could consider. Sharing the findings could help companies pick up best practice and inform policy makers in developing new frameworks for improving industrial sustainability

Development of a Rough Terrain Wheelchair Design

Conventional wheelchairs do not cope well in less-resourced rural areas as they are not stable and can topple easily. This chapter seeks to develop a wheelchair design that offers optimum stability and comfort for people in rural areas where there is rough and uneven terrain environment. The design development process entailed the generation of three possible wheelchair design concepts. Wide rear wheel design was further developed to come up with a detailed design with a maximum tipping angle of 43.17 degrees. This could be considered to be a great improvement compared to the conventional wheelchair configuration. The design was made to function using a ratchet lever bar to push the rear wheels forward to initiate motion. It was established that fabrication of the prototype could be done easily at a lower cost cap of USD200 using locally available materials. The proposed wheelchair design would improve the mobility and consequent living conditions of those disabled individuals living in rough terrain rural set up environments

Towards green manufacturing : improving environmental sustainability in the Zimbabwean steel industry

D.Ing. (Engineering Management)Abstract: This research focused on identifying ways of contributing towards green manufacturing by improving environmental sustainability in the Zimbabwean steel industry. The research was carried out through literature search, industrial surveys that included interviews of key personnel and the use of a questionnaire, and experiments to verify a hypothesis that was formulated. The industrial survey utilised the Delphi approach in order to explore the strategies, tactics and practices that the companies in the steel industry are currently implementing, and other improvements needed in order to ensure economic, social and environmental sustainability. It also identified current processes and any mitigation methods in place to mitigate emissions of toxic gases and allowed for interviews of key personnel from which a questionnaire was then formulated. The main concern for all the companies represented was that policies need to be investor friendly as that would lead to economic sustainability which in turn would lead to improved social and environmental sustainability. The results of the survey were distributed to all participants for further implementation of possible environmentally friendly practices. From the survey a hypothesis was formulated that cupola furnace slag may be used as a lubricant in the cutting of steel. Two samples of the cupola furnace slag were collected from two different companies and ground into powders. Experiments were set up using soluble oil as the control experiment and the powders were used as dry lubricants and Vaseline was added to produce a paste. The results showed that cupola furnace slag may be used as a lubricant in the cutting of steel as it outperformed oil-based cutting fluids. It has lubricating properties and is capable of inhibiting heat diffusion. Another industrial process investigated was calcination for a new start-up company. Calcination is an endothermic reaction that converts limestone into lime. Making the calcination process greener was studied and ways of achieving this were identified as: addition of chimneys to the kilns to increase draught column and allow preheating of limestone, addition of exhaust allowing the flue gases to pass through an amine system as a means to strip the flue gas of CO2, and use of insulating material such as vermiculite between the inner brick skin and outer brick layer to optimise energy utilisation. The main contribution to knowledge was that a new solution to the utilisation of cupola furnace slag was established. This will economically assist the companies by cutting out the purchases of soluble oil and commercializing the use of cupola furnace slag in cutting. Reduction of cupola furnace slag in landfills is a great contribution towards sustaining the environment and greener manufacturing. The selection of slag that has a high aluminium and silicon content will help in its use as a solid lubricant in dry drilling. It is also noted that both aluminium and silicon are key constituents of coatings for cutting tools. Promoting dry drilling will also advance sustainability by reducing the use of oil-based cutting fluids thus cutting costs and eliminating the environmental burden of oil usage. The Industrial Impact was that companies that took part in the study are very happy with the results of the dry drilling. They now have a low-cost consumable for machining for their in-house operations or for commercialisation. Wider sustainability factors for Zimbabwe steel industry were also covered. The study has developed and documented the industry preferred solutions for promoting the revival of the Zimbabwe steel industry. The three main contributions to knowledge made by this research are solutions for the revival of the Zimbabwe steel industry, a new method for deriving value from slag waste and firm proposals for reducing emissions in the calcination plant

Designing a Quenching System for Grinding Steel Balls - Case Study

The availability of grinding balls of superior quality than those produced at a Harare company in Zimbabwe, resulted in loss of business. In order to retain business, a new ball that has a similar chemical composition to that of imported grinding balls was developed. Proper thermo-mechanical treatment has to be done after casting, in order for the ball to be of satisfactory quality. In this research, heat treatment tests were done on the developed ball to determine a suitable quenching medium for the heat treatment cycle. Using the results of the heat treatment tests obtained, a suitable heat treatment cycle which utilises optimum quenching medium and has effective agitation for minimal defects was designed

Success factors for manufacturing and service industries in Zimbabwe

The paper analyses how Industrial Engineering (IE) ideas may be applied to the Zimbabwean industry and the benefits that can be drawn from this discipline in order to improve the operations in Zimbabwean Industries

Design of a ferrochrome – slag mechanical separator case study

This research focused on the design of a ferrochrome – slag mechanical separator for a company in Harare, Zimbabwe. The company’s current production is 420 tonnes of alloy per month. The aim of project is to raise the production from 420 to 500 tonnes of ferrochrome production per month by introducing a mechanical separator at metal recovery plant that produces 80 tonnes. The difference in specific gravities of ferrochrome and slag is the key principle applied in achieving separation of the two products. The densities of ferrochrome and slag are 6800 kg/ m3 and 2800kg/ m3 respectively hence gravity separation method in water medium can be done