Batching Structure Of High Carbon Ferrochromium Smelting

Chromite is an important raw material for producing ferrochromium alloy.However,chromium ore is a scarce mineral resource in China.In 2011,the national proven reserves of chromium ore resources were 11.611 million tons.93% of China's chromium ore needs to rely on imports.In 2014,the chromium ore output was 28.68 million tons,and the consumption of commercial grade chromium ore was about 29 million tons,resulting in a shortage of supply and demand.How to use low-priced fine ore and domestic lean ore to reduce production costs and enhance the competitiveness of enterprises is the main research direction.In this study,ferrochrome concentrate and low-grade chromium ore are used as raw materials,and the optimal mix structure and operation parameters are obtained by sintering and pressing balls,so as to reduce production costs.In this paper,the sintering experiment of chromium concentrate is carried out,and a certain amount of balls and pellets are purchased to study the process of smelting high carbon ferrochromium in electric furnace.The main contents of this experiment include the sintering experiment of ferrochromium concentrate powder and the optimization of technological parameters of production test of various products in electric furnace reduction smelting,and the sintering and consolidation mechanism of ferrochromium concentrate is studied.The sintering test of ferrochrome concentrate shows that the optimum fuel ratio of South Africa chrome ore powder sintering is 13% under the test parameters of ignition temperature 1100±50?,ignition time 300 s,ignition negative pressure6000 pa,sintering negative pressure 10000 pa,material layer height 700 mm,moisture9-11%.Bentonite is used as binder.In the experiment,4% addition can strengthen the granulation effect of South African chromium ore powder,improve the permeability of the bed,optimize the sintering process index.The maximum utilization coefficient in laboratory is 0.56t/platform.h,and the ratio of bentonite in industrial production is appropriately increased to 6%.After sintering process,chromium ore is reduced to varying degrees.Metal chromium exists in sinter.The reduction degree of chromium ore is between 13.76% and 24.88%.The production practice of electric furnace shows that the slag with high Mg2+ or Mg O/Al2O3 is easy to produce strong crystallization when the temperature drops to about 1600 ?,and the alloy particles are mixed in the slag too late to sink,which leads to the decrease of metal recovery.Through practical exploration,the Mg O/Al2O3 control in our company is the most suitable.In the smelting process,the recovery rate in the early stage of smelting increased rapidly,but after entering the refining period,the recovery rate decreased rapidly.The sinter and ball pressing ball in single furnace smelting time were controlled within 140 min,and the ball pressing ball was controlled within 160 min.The theoretical slag temperature is 170.At 0?,the superheat degree of the control slag is optimal at 120-150?.