Guizhou Xingyi Gangue's Activation Research And The Experimental Exploration Of The PAC Preparation

Coal gangues are one of the largest solid wastes in China's mines.At present the mountains of gangues are more than 1,900,accumulated waste dumps are about 3.8 billion tons,and the floor areas cover over 70 km².Moreover the mass rate of emissions gets to 150 million tons a year.Coal gangues not only occupy land,but also seriously affect the surrounding air,water and soil,and damage the ecological balance.So the study of coal gangue has drawn increasing attention in recent years. We strengthen the research of the using of coal gangue resources,so that solid waste can be transformed into the use of resources.It is not only saving the limited mineral resources,but also protects the ecological environment and realizes the continued development of society.Gangue has two characteristics:On the one hand, coal gangue is solid waste emitted in the coal production process;On the other hand,coal gangue is non-metallic mineral resources composing of rocky and gangue mineral and they have the available attributes.Because the composition of gangue is different,its use is not the same way.The key of the use of coal gangue resources is to the correct analysis of the special resources properties,find the best activation temperature,and choose the optimization method and technology of reasonable resource use,so that the technique is feasible and economy is beneficial.This paper chooses the Gangue of Guizhou Xingyi as raw materials.The mainly composition of coal gangue,the optimum activation temperature and the activation mechanism are investigated and based on these studies,the preparation of inorganic polymer flocculants(IPF) has been explored using the gangue,and the flocculant of PAC has been successfully prepared.The results obtained from the above researches are summarized as following: 1.The major compositions of the gangue are studied by XRF.Analysises for XRF show the main chemical compositions of the Gangue of Guizhou Xingyi are SiO₂ and Al₂O₃,SO₃,Fe₂O₃,N₂O₅,CaO,K₂O,TiO₂,MgO,Na₂O and Cr₂O₃.The trace components are P₂O₅,ZrO₂,SrO and NbO.According to the experimental results, it can be seen that Guizhou Xingyi Gangue should belong to clay waste rock, which the contents of Si,Al and Fe are high.This provided helps to the application study of gangue.2.The decomposition mechanisms of different calcined temperatures and the optimum calcined temperature of the gangue are studied by XRD and FTIR. Analysises for XRD and FTIR at different calcined temperatures show that kaolinite and mica take place dehydration reaction as the temperature increases. The contents of activation of SiO₂ and Al₂O₃ are increased,so the activity of gangue increases.But calcined temperatures above 800℃,the activation of SiO₂ and Al₂O₃ take place reaction and produce andalusite,so the activity of gangue decreases.Based on the above experimental results,the optimum calcined temperature of the gangue from Xingyi Guizhou is 700℃.By the study for the optimum calcined temperature and the activation mechanism of coal gangue,this provided a strong experimental evidence and theoretical support to the use of coal gangue resources.3.Gangue as the basic raw material to prepare inorganic polymer flocculants(IPF) does not produce new environmental pollution,but achieves comprehensive utilization,reduce product costs,and improve the added value of the product. This is channel of cost-effective processing for gangue.According to the compositions,optimum activation temperature and the activation mechanism of Guizhou Xingyi Gangue,polyaluminum chloride(PAC) has been successfully prepared.The optimum technological conditions has been obtained.