Study On Extracting Alumina From Fly Ash

Aluminum is very important in life and industrial, applied in all walks of lifeincreasingly.And function is great,from our aluminum instruments used in daily life to someparts and components manufactured in aviation. Traditional aluminium make process isthrough the mining bauxite, mineral processing and smelting processes to make the metallicaluminum.But in China the high quality bauxite resources extremely limited, with the rapiddevelopment of our economy, the demand for aluminum is becoming more and morelarger,so the founded bauxite resources reserves has been difficult to meet the needs ofaluminum to the social development obviously. In order to realize the sustainabledevelopment of the economy, we have to find new bauxite resources, to expand the reservesof bauxite. And looking for new aluminum resources form actively, as bauxite alternativeresources to ease the tension situation of bauxite. In this context, our predecessors, after a lotof exploration noticed fly ash, especially high-alumina fly ash, in some place the fly ashincluding aluminum can be as high as30%above, if this part of the aluminium can beleached will ease the situation of bauxite nervous at present greatly. This topic is establishedunder this situation.In reference to the previous, especially the successful experience ofHenan Sanmenxia, making experiments.First, study on technological mineralogy of the fly ash (from no.3boiler in baotouxiwang aluminum power), including sampling, observed by microscope, chemicalcomposition analysis and grain size analysis, etc. Then combine the results of study ontechnological mineralogy, based on the successful experience of other people experimentalexploration, find the suitable process to study the fly ash, finally determined to use sulfuricacid leaching method, i.e. in heating mixing condition, and leaching with sulfuric acid. Afterdetermined use sulfuric acid leaching method,there are a series of tests to establish the bestvalue for each condition, and the considering conditions are: temperature, time, leachingconcentration, acid concentration,and finally achieved such a good results: the leaching rateof70%above. Through the large number of experiments, leaching aluminum with sulfuricacid just with the original ash, liquid density is40%, acid (sulfuric acid) degrees is66%, andthe temperature is100oC or so, time for1hour, in these conditions can obtain the leachingrate is70~80%.And then studied the process of iron-removal and high temperature calcination topreparate alumina. And after many times use EDTA complex remove iron method and potassium permanganate oxidation precipitation method, finally determined use thepotassium permanganate oxide precipitation method. In the condensed stage due to thelimited of the experimental conditions,the results are not ideal,so need to be furtherstudied,and calcination is used aluminum sulfate calcinate directly.