Coal gangue is a kind of coal-bearing kaolinite associated with coal and a kind of solid waste discharged during coal mining and coal washing. The output of coal resources in our country is huge, so there is a large amount of solid waste emission of coal gangue. The high value-added comprehensive utilization is of great significance to the economy, the environment and the society. The neutralized slag acid leaching substances of coal gangue was used to extract the valuable elements from the acid solution. The effects of dissolution temperature, dissolution time and mass ratio of liquid to solid on the dissolution process of acid solution were researched in this work. Based on the single factor experiment, the dissolution conditions were optimized by these orthogonal experiments. The phase and micro morphology of the neutralized slag acid leaching substances of coal gangue, the acidified product and the acid slag were analyzed by XRD and SEM. The results indicated that the dissolution rates of valuable element oxides were TiO2 82.63%, Fe2O3 96.48%, Al2O3 98.33%, CaO 87.72%, MgO 95.31%, respectively, when dissolution temperature was 80℃, dissolution time was 40 min, mass ratio of liquid to solid was 3:1. Only SiO2 and a small amount of TiO2 were found in acid slag after neutralization residue dissolved. The existence of CaSO4 indicated that the valuable elements in coal gangue and residue acid were fully dissolved through this process. This method had the advantages of short dissolution time, less water consumption and higher dissolution rate of valuable elements in acid leaching system. With this research, it is expected to provide a new approach for the efficient utilization of coal gangue resources.
Guangya ZHENG Zhengjie CHEN Jupei XIA Weijie WANG Fang GU Yibo SHI Haolin LI Wanlin LI Chenglong LIU
. Dissolution of neutralized slag acid leaching substances of coal gangue[J]. The Chinese Journal of Process Engineering, 2020
, 20(2)
: 174
-181
.
DOI: 10.12034/j.issn.1009-606X.219178
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