Study On The High Efficiency Separation Technology Of Aluminosilicate From Potassium Silicate Treated By Fluorosilicic Acid

The shale with potassium is a kind of insoluble potassium mineral, which is rich of K2 O, abundant, excellent in quality and widely distributed. Since 1950 s, lots of researches and exploitations about the insoluble potassium mineral have been conducted to product potash fertilizer in our country. In Guizhou province, there are almost a hundred mineral occurrences with potassium shale, among which more than a dozen mineral occurrences reserve tens of millions of potassium shale, and Tongren ore belt has a reserves more than 5 billion tons.In this dissertation, we mainly focus on the research of potassium shale exploited from Tongren wanshan, in Gouzhou province. Through chemical study and XRD analysis, the main chemical components K2 O, SiO2 and Al2O3 can be found, with a sum of the three more than 85%. Through silicate decomposing the potassium shale, we can study the extraction and separation ferro-silico aluminium. In terms of properties of intermediate, fluorine and silicon of intermediate can be volatilized by concentrate sulfuric acid, while iron and aluminum can be turn into dissoluble salt. As the ratio between the original mineral powder quality and amount of sulfuric acid is 1:0.6, the extraction ration of aluminum and iron from intermediate can reach 95.3% and 86.8% respectively. The dissoluble ferric sulfate and aluminum sulfate can be dissolved absolutely, as dissolved water volume and washing water volume is 4 times and 1 times of ore powder respectively.The level 3 organic complexing precipitation is employed during experiment, and the optimal process condition for single factor experiment can be determined. The primary separation process: the ratio of quality of iron and DDTC is 1:8, the pH of solution is 1.8, reaction temperature is 35℃, reaction time is 10 min, the separation rate of iron from solution is 74.6%. The secondary and tertiary separation process: the ratio of quality of iron and DDTC is 1:10, the pH of solution is 1.8, reaction temperature is 25℃, reaction time is 5min, the separation rate of iron from solution can reach 99%.The complex of iron can react with alkali to produce ferric hydroxide which can be calcined to obtain ferric oxide. The optimal process condition for single factor experiment can be determined: the ratio of solid to liquid for Fe-DDTC and KOH is 1:50, reaction temperature is 60℃, reaction time is 2h, the amount of polyethylene glycol is 3ml, the purity of obtained ferric oxide is 91.2%. The optimal process condition for single factor experiment of producing aluminum oxide can be determined: reaction temperature is 60℃, reaction time is 0.5h, the pH of reaction system is 8, the purity of obtained aluminum oxide can be 92.3% as the mass fraction of ammonia is 15%.