Includes bibliographical references. / The matte converting furnace s are found at the heart of the copper and nickel smelting processes where oxygen contained in air and industrial oxygen is used to oxidise iron in the furnace matte to produce blister copper or the iron free matte suitable for treatment in the downstream processes. A fundamental knowledge of the base metals matte smelting and converting processes system is valuable for maintaining a stable and optimum process operation. A mathematical model for the Ni - Cu - PGM matte converting process has been developed based on the assumption that the converting process is both in chemical and thermal equilibrium. The converting process demonstrated by the model is the Top Submerged Lance (TSL) base metal continuous converter that treats Ni - Cu - PGM furnace matte similar to the one utilized at one platinum smelter. The TSL PGM converter was chosen for the reasons that the Ausmelt/Isasmelt TSL smelting furnaces are high ly productive flexible smelting and converting units and environmentally friendly, that requires a low capital cost compared to other smelting processes. The model predicts the masses of the process inputs of air, oxygen, fuel coal or oil, silica flux and the outputs components contained in the three product s high grade matte, slag and offgas. The mathematical model utilises the matrix - inverse method that is used to solve the matrix representing a system of several linear equations to give the values of unknown variables. The mathematical matrix - inverse method provides us with the tool to solve many large linear equations arranged in a square matrix numerically to gives solutions. The matrix - inverse method was chosen because it is part of windows excel formulas as MINVERSE and MMULT formulas which is accessible on most computers with Microsoft windows program. The inverse of the matrices is solved using the Gauss - Jordan mathematical method. The study found that the matrix simulation model is able to give accurate predictions of the masses of the industrial TSL converter process inputs fuel, air, oxygen, and silica flux as well as the process outputs masses of the components of converter matte, slag and offgases. The model also indicated that changes in the feed matte composition, moisture in feed , matte feed rate, oxygen enrichment, bath operating temperature and fuel type results in change in one or more of the process inputs requirement and masses and composition of product phases. The simulated model results compare very well with the industrial plant process parameters sourced from one of the platinum smelters that use the TSL technology for converting furnace matte. The results predicted by the model provides good insight into the operations , control and design of the TSL Ni - Cu matte converter and therefore the model is regarded as an invaluable asset for predicting the process dynamics of the present and future converting units. The model provides a good understanding of the base matte converting process and as such will serve as a useful tool in improving and optimising the base metals converting processes without carrying out extensive and expensive tests. It is concluded from the study that the mathematical matrix - inverse calculation method is suitable for modelling the smelting and converting processes of the Ni - Cu - Fe - PGM matte in the TSL converter. The model results were validated through comparison with actual plant operating parameters sources from the relevant platinum smelter which indicated an accuracy of over 9 0% on most parameters. The modelling of the base metal smelting and converting processes has valuably been furthered, however for complete confidence in the model results, further validation is recommended using other simulation softwares and methods.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uct/oai:localhost:11427/14563 |
| Date | January 2012 |
| Creators | Kabwe, Joseph |
| Contributors | Mainza, Aubrey, Simukanga, S |
| Publisher | University of Cape Town, Faculty of Engineering and the Built Environment, Department of Chemical Engineering |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Master Thesis, Masters, MSc |
| Format | application/pdf |
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