Biomass reduction of manganese ore in the presence of carbon monoxide

Abstract: The ferromanganese industry is currently strained by the cost of production that is continuously increasing. Alternatives of reductants are being sought to try and alleviate the production costs namely solar energy, wind and biomass. Some studies on the possible use of biomass using the South African manganese ores were conducted and as preliminary results were generated. The South African manganese industry has focused more on the pre-reduction. The current paper focuses on the use of raw macadamia nut shells for the reduction of manganese ore in the presence of carbon monoxide. The feed and products were characterized using XRD, XRF as well as SEM and compared to products currently obtained using conventional reductants. The basicity of the feed was kept at around 1. The temperature was set at 1450oC, a graphite crucible placed in a silica crucible to prevent any spillages. Comparisons between products obtained when raw macadamia nut shells and conventional reductants were used was done. It was found that macadamia nut shells have great potentials of replacing the conventional reductants used so far. The separation of slag from the metal needs imporvement as the slag structure was more needle-like and some metal entrapments were noticeable as compared to conventional process

Use of macadamia nut shells in the tin production and their effects on the slag

Abstract: Conventional reductants have been and are still being used for most of the high temperature reduction processes. However, new reductants are being sought for. Macadamia nut shells were used as reductant in this investigation and their effect on the slag. Cassiterite containing Nb and Ta have been used in this investigation. The basicity of the feed was kept at 1 through the addition of CaO-bearing material as a flux. The raw macadamia nut shells were characterized using proximate and ultimate analysis, XRF, XRD, SEM-EDS and FTIR. The ore and flux were analyzed using XRF, XRD and SEM-EDS. Experiments were conducted using an alumina tube furnace. The temperature was set at 1450 oC, a graphite crucible placed into a silica crucible was used for the experiments. Reduced products were characterized and compared to the products currently obtained using conventional reductants. Products obtained when raw macadamia nut shells were used and when using coke were compared. Results show that macadamia nut shells present great potential to use as reductants in tin industry on condition of further investigations on optimization. The slag produced presented a more needle-like structure as opposed to the conventional process that presented a glassy slag

Effect of CaO/MgO ratio and basicity during tin smelting on the metal and slag formation (II)

Abstract: The current demand of some specific metals (alloys) in the HiTech industry has pushed researchers to increase the number of investigations to improve the quality of products on the market. Generally, coltan is a byproduct of tin metallurgy and is collected in the slag. The formation of phases in the slag needs to be investigated in order to optimize the collection of coltan in specific phases by trying different ratios in fluxes. Also, cassiterite is associated with iron ores and during smelting the iron get reduced together with tin and ends up contaminating the metal. The basicity is always a useful parameter that govern the behavior of the slag. Basicity was varied through addition of CaO and MgO. The CaO/MgO was varied by changing CaO and keeping MgO constant as opposed to previous study where CaO/MgO was varied by changing MgO and keeping CaO constant. Different basicities of 0.8, 1, 1.2, 1.3 and 1.4 were used..