| Red mud is the alkaline solid wastes discharged from alumina during smelting process, in addition to contain a variety of metal oxides, valued metals and other active ingredients, while also containing4%-9%(Na2O+K2O) and ignition loss, its strong alkaline and is difficult to be effectively utilized. Along with the rapid development of aluminum industry, the amount of the red mud has increased dramatically which bring about environmental pollution and comprehensive utilization issues concerned. The study comes from Henan province major commonweal scientific research project, aimed at reducing the content of alkali in red mud, so that resource utilization in building materials, agriculture and other fields.The study of early lab trials in the red mud dealkalization process was successful, on the basis of this, designed and installed the industrialization of the enlargement test device in the Great Wall of China Aluminum Corporation,verified the optimal conditions of dealkalization process on laboratory tests, to obtain better amplification process conditions.The methods for bauxite chemical analysis, XRD,sieving method, SEM and other means were analyzed and compared for the composition and phase characteristics of the red mud off before and after alkali.and the red mud dealkalization after for silicon fertilizer production is studied, in order to realize the red mud of agricultural scale application.This paper selects PC400x300hammer crusher, vibrating screen (screen aperture5mm), MQG900×2100Dan Cang wet overflow type ball mill, DU0.8/500-A rubber belt vacuum filter and other equipment, using a continuous feed milling, two acid continuous feed milling process, the sintering red mud off the alkali test results showed that, the red mud slurry solid content on the ball milling effect little, but for the test device, the use of the solid content of30%slurry is more appropriate.The red mud slurry solid content of30%, adding acid (from the original red mud by removing3.81%Na2O required sulfuric acid measurement) to take off the alkali, off alkaline red mud slurry after filtering, washing, drying, decreased the content of Na2O51.44%, K2O decreased by38.06%, alkali removing effect was good, basically achieved the expected goals, the amount of dealed with red mud every day was about in10-15t.In addition, the use of this technology in Bayer red mud off the alkali exploratory test.The results showed that, the content of No2O is reduced by25.04%, K2O only decreased by12.29%, alkali removing effect is not good.In addition,, through the ball mill milling thinning, red mud particle morphology was changed, greatly improving the content of active components. In the sintering red mud after the removal of alkali based on XRD analysis, the active silica and active calcium content could reach above50%, and containing Mg, P, K and other nutrients plants required, which could be directly used in the production of silicon calcium fertilizer after dry ball milling. Applied fertilizer made of red mud off alkali Xinyang Luoshan in2011spring rice experimental field, rice yield of about15%, with early maturity, fewer pests and diseases, lodging resistance and other characteristics. At the same time in order to achieve the red mud silicon fertilizer industrialization as soon as possible, guarantee of product quality, specification of red mud silicon market, to promote its healthy and rapid development, the initial formulation of the red mud fertilizer enterprise standard was made.Finally, according to the economic evaluation, the production equipment, this production unit with annual production capacity was up to5475tons, in accordance with the annual processing5000tons, the red mud addition amount about70%to produce silicon fertilizer, annual sales volume is about7000tons,800RMB/ton, the annual net profit was about2590700RMB,with good economic benefit and application value, at the same time, also for red mud achieve scale application provided theoretical basis and technical basis. |
PDF Full Text Request