影响酸法提取煤矸石中氧化铝主要因素的试验研究

Affecting factors on the alumina extracting from the coal gangue with sulfuric acid

对煤矸石中有用元素的提取,是煤矸石深度利用开发的一个方向。从山西柳林煤矸石入手分析其组成与结构,采用X射线衍射来分析不同煅烧温度下煤矸石的晶型变化。研究了煤矸石在硫酸介质中氧化铝浸出的影响因素,较好的工艺条件如下:煤矸石活化温度为750℃,酸浸温度为100℃,酸浸时间为4 h,酸矸比为1.1∶1,固液比为1∶3。在此条件下Al2O3的浸出率可以达到85.2%。

This paper is engaged in a study of the affecting factors on the alumina extracting from the coal gangue with sulfuric acid method.As is known,coal gangue is the largest emission of the solid waste in modern coal-mining trade.Therefore,it is extremely significant to extract useful chemical ingredients from the coal gangue and utilize it for economic profits.For this purpose,this paper has done a scientific analysis of the composition and structure of the coal gangue produced from Liulin coalmine,Shanxi,by using X-ray diffraction at different calcination temperatures.After the analysis of the given coal gangue,we have made a proposal to use the lixiviation of alumina from it.And,then,we have decided to use the optimum conditions and investigated all the conceivable factors that may influence the retrieval of alumina from the coal gangue.The results of our intensive experiments show that the main factors influencing the removal include heating temperature,acid leaching temperature,reacting time,ratio of acid/coal gangue,and the solid/liquid.Of all the influencing factors,acid leaching temperature and reacting time are the chief ones.According to the analysis done,we have chosen,among all the technological conditions,that heat activation temperature should be 750 ℃,the acid leaching temperature（100 ℃）,the acid reacting time（4 h）,with the ratio of acid/coal gangue being 1.1：1 and that of solid/liquid（1：3）.And the leaching rate of alumina should reach 85.2%.As to the acid residue,the experiments show it is impossible to lixiviate feldspar and mica mineral crystal aluminum from the minerals due to the restricted technical conditions.As to the valuable bauxite,since it will be run out in our country till the next decennium,we have to pay special attention to look for new alumina resources for future sustainable development along with the conservation of resources and environmental protection.