Study On Purification Process Of Quartz From Gold Tailings And Its Safety Evaluation

Conglomerate type gold ore is one of the important gold ores,due to the low content of gold elements,only 3 to 5g/t,the gold extraction process needs to pass through crushing,ball milling,beneficiation and other processes.A large amount of tailings are stacked for a long time,occupying a large amount of land and causing environmental pollution around the mine site.Its tailings have a high content of quartz fraction,which is a potential high purity quartz resource.This thesis takes a conglomerate type gold mine tailings in Yantai as the research object,and explores the use of flotation and acid leaching to purify quartz from the tailings by analysing the presence of impurity phases in terms of morphology,morphology and components,and proposes a flotation combined with acid leaching process,and evaluates the safety of its process.The main conclusions are as follows.The tailings of a conglomerate type gold mine in Yantai are mainly composed of quartz and sodium feldspar,and also include a small amount of potassium feldspar and mica,with Si O₂ content of 81.2%,Al₂O₃,Na₂O,K₂O,Ca O,Fe₂O₃ and Mg O content of11%,4.1%,2%,1%and 0.2%,respectively.The Ca and Fe elements in the tailings are inlaid on the mineral surface as oxides or metalates,and sodium feldspar,made up of silicates,is the main impurity phase.The optimum parameter conditions for quartz reverse flotation were determined through mineral flotation tests and adsorption mechanism studies:the particle size was controlled at-0.075mm,sodium oleate and dodecylamine were used as anionic and cationic trapping agents,the molar ratio was 1:2,the concentration of trapping agent was 100mg/L,and the recovery of concentrate was 50.3%and the Si O2 concentration was increased from 81.2%to 96.35%,in which the removal rates of four impurity elements of Al,Ca,Fe and Mg were 84.7%,48%,80%and 99%respectively,with obvious purification effect.In the acid leaching test,3 mol/L H₂SO₄ and 1 mol/L HNO₃ were used to remove the impurities from the flotation concentrate at 10h,1:10 solid-liquid ratio and 80°C.The Si O₂ concentration increased from 96.35%to 99.32%,and the concentrations of Al,Ca,Fe,Na and K were 0.11%,0.01%and 0.0.01%respectively.0.01%,0.025%,0.08%and 0.06%respectively.The main risks present in the tailings purification process are hazardous chemicals,dust hazards,mechanical equipment hazards,etc.The hazards caused by mineral dust are highly hazardous sources with a hazard class II,while the explosion hazards caused by hazardous chemicals and the water extraction system are class III,requiring high attention from the enterprise.