Pink Quartz System To Take The Study Of Electronic-grade Crystalline Silica Powder

In this paper, the flotation separation mechanism of silicate mineralsbetween quartz and clinochlore was studied. Furthermore, the mechanismand effects of reverse flotation and acid treatment were investigated in thepreparation of electrical and electronic grade silicon powder. In theexperiment, all steps were optimized, and then electrical and electronicgrade silica powder was prepared.Due to the similar structure, silicate minerals were separateddifficultly from each other. Then the research focused on the study of therelationship of crystal structure, zeta potential, contact angle, surfacecharacteristics and the floatability of the two minerals. Research showedthat the two minerals all have floatable behavior.In order to study on the adsorption mechanism of reverse flotationseparation between clinochlore and powder quartz, oleic acid was used asanionic collector. The solution property of oleic acid was analyzed.According to the fact that the two minerals dissociate in the solution intodifferent activity centers and through infrared spectroscopy, it wasdetermined that clinochlore, not powder quartz can be absorbed by oleicacid in chemical way. Therefore, clinochlore and powder quartz can befurther effectively separated.The influence of pH, concentration of oleic acid and flotation time tothe recovery were tested. The content of SiO₂ in the raw materialsincreased from 98.26% to 99.76%, and the content of Al₂O₃ reduced from0.82% to 0.18%, as well the content of Fe₂O₃ reduced from 0.77% to0.12%. The product has basically reached the level of electrical standards.Sodium dodecylsulfate as anionic collector was also studied, thenthe pH and collectors concentration were considered on the recovery ofSiO₂. The results showed that the content of SiO₂ could only arrive at99.41%. Accordingly, the separation results showed oleic acid as anioniccollector got higher content.The results were determined by analysis of mineral composition,chemical composition, physical and chemical properties, phase analysis, particle shape and size distribution. To further remove impurities andimprove the content of SiO₂, acid treatment was used after reverseflotation. Factors affecting the purity of SiO₂ were observed, such asscrubbing time, pulp density, the amount of dispersing agent, the differenttypes of acid and wash water etc. The final product was prepared andmeets the standard of electronic grade silicon powder requirements ofSJ/T10675-2002, while the content of SiO₂ is 99.86%, Al₂O₃ is 0.09%and Fe₂O₃ is 0.010%.