Study On Preparation Of New Coal-based Alternative To Charcoal Reductant In The Industrial Production Of Silicon

Industry silicon need amounts and day drama increase with the fact that semiconductor estate and brightness vanquish estate's quickly development. The industry silicon belongs to but high energy consumption estate. It adopt silica as raw material mainly, charcoal material as the reducer, and produces industry silicon within electric heat stove. For a long time, charcoal is to be used for silicon smelt as the best reducer. But attack with strengthening that environmental protection is aware of, the forest taboo, the source of goods having led to that charcoal has been short-supplied, price has gone up by a wide margin. So it has affected the economic effect on silicon enterprise gravely.To resolve the short-supplied problem of sources of energy in silicon industry produce, developing out one kind reducer which is more broad, cheaper charcoal of price is imperative. Study originally specifically for this problem, adopt a source to be more broad, relatively lower of price as raw material to preparate new model coal reducer.This study adopt bituminous coal and azabache as raw material to develop a new caol base reducer used for industry silicon preparation replacing charcoal mainly restores originally. Specifically for the problem that when bituminous coal as a reducer, the various function fairly good but ash content is high, so it adopt the oil birdnesting selectivity flocculation law to take off ash and prepare low disheartened clean coal to fit in produce need. And Yunnan azabache is besides, in the light of abound in natural resources, cheap azabache price characteristic, take azabache as raw material adopting middle low temperature to destructive distillation to be in progress to have carbonize treatment, strip off most moisture content in azabache and be volatized to get fairly good azabache of function mark—half coke. By the component analysing azabache half coke ash content, there exist in the main form with the metallic oxide specifically for among them harmful foreign substance, adopt a chemistry to take off the ash.Be made half coke with extra care to apply to the industry silicon produce.The reducer short-supplied problem which exists in silicon smelting process at present have been resolved, further more, the coal price is lower than charcoal. So the production costs will be lowerBy the fact that the experiment studies the main influencing factor handling the person as well as the clean coal function determines, but gets(1) the birdnesting carrying out oil on bituminous coal to take off dust grain diameter having coal, size, water coal thick fluid thickness size, birdnesting agent paint dosages and flocculation time. And the grain diameter by the fact that the Shan factor experiment gets coal is 250 eyes, water coal thick fluid thickness is that experiment effect is optimum when 0.033 g/mL, oil dosages are that 10mL, flocculation time are 10mins, bituminous coal ash content may fall to 4% from 11.61%, may be used for industry silicon childbirth theoretically. (2) Azabache adopt middle low temperature destructive distillation preparation to get various fairly good function azabache to Yunnan half coke, the dust being in progress by analysing ash content among them staple coming off handles, gets the best condition: Carbonize the end temperature being 500℃, acieration time is that 1 h preparation gets azabache half coke, acid soaks half coke grain diameter being 0.5mm＜r＜1 mm, chlorhydric acid thickness is 5 mol/L, liquid strengthens ratio being 5, acid soaks time being 24 hours, coke ash content may descend from 10.30% for 6.04% partly, the among them take off iron rates having reached 73.78%, harmful component diminishes by a wide margin, but is used to temper a silicon with fire.The technical economy testing that the environment having been in progress appraises a sum to industrialization appraises the main body of a book. This industrialization tests 1000 t/a producing scale (reach the product year) being 50,000 t/a processing raw material azabache, producing a depth taking off 10000 disheartened partly burnt t/a and tar oil. The general fund that the project throws into is 9 million yuan, the annual income from sales of products is 11,200,000 yuan, the altogether mixes to estimating economy life-span in 10 scheduled time into, 3,929,300 yuan for the country and place pay 6,025,600 yuan of tax, among them, investment profit rate is 29.11%, the rates investing in profit and tax are 35.77%, sell profit in main project economic target.