Reduction characteristics of coal-bearing briquettes of nickel laterite ores and preparation of Fe-Ni alloy by high temperature melting and separation
Fe-Ni alloy was prepared from carbon-bearing briquettes with nickel laterite ores by the process of carbo-thermal reduction and high temperature melting.The different mineral properties between limonite laterite ore and saprolite laterite ore and their effects on the oxygen-loss rate of iron and nickel-bearing minerals in the process of carbothermal reduction of the carbon-bearing briquettes at different temperatures were studied.The relationship be-tween Ni content and the comprehensive yield rate of valuable elements in Fe-Ni alloy products prepared by high temperature melting with pre-reduction products and the properties of nickel laterite ore and the C/O molar ratio in coal-bearing briquettes had been analyzed.The results show that the reduction temperature has a great influence on the carbothermal reduction of saprolite laterite ore.Sample with C/O molar ratio 1.2 can be fully reduced to metal Fe and Ni only after 30 min reduction at 1 200 ℃.At a lower temperature as 1 100-1 150 ℃,even if the reduction time is infinitely extended,the reduction rate couldn't be further improved.But for the carbon-bearing briquette of limonite laterite ore,it can reach a reduction rate both Fe and Ni above 90％after carbothermal reduction at 1 150-1 200 ℃ for 10 min.After the carbon-bearing briquette is pre-reduced at 1 200 ℃ for 30 min,then heated to 1 600 ℃ melting for 30 min,the Fe-Ni alloy is separated out from melting slag.The Ni content of Fe-Ni alloy separated from carbon-bearing briquette of limonite laterite ore by pre-reduction and melting is decreased with the increase of the C/O molar ratio.On the contrary,the Ni content of Fe-Ni alloy separated from carbon-bearing briquette of sa-propelic laterite ore by pre-reduction and melting is increased with the increase of the C/O molar ratio.The carbon-bearing briquette with the C/O molar ratio less than 1.0 could inhibit the reduction of iron-bearing minerals in sa-propelic laterite ore,but it has a stronger inhibition on the reduction of nickel-bearing minerals,which ultimately af-fects the comprehensive yield rate of nickel and reduces the Ni content in Fe-Ni alloy.This study can provide guid-ance for the development of new pyrometallurgical extraction technology of nickel laterite ore and the efficient utiliza-tion of nickel laterite ore to produce Fe-Ni alloy.
nickel laterite oreFe-Ni alloycoal-bearing briquettecarbothermal reductionhigh temperature melt-ing
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