Study On Preparation Of High-purity Calcium Carbonate

As filler, Calcium carbonate is extensively applied in rubber, plastics, printing ink, paper, food and electronics industry. In recent years, with the rapid development of science and technology, each profession requests it develop into the direction of super-thin and high-purity, the study of high calcium carbonate is taking on board too.According to the demand of electronics industry, this topic is ascertained. In this study, it was put forward firstly that the industrial calcium nitrate was used as the raw material to prepare high-purity calcium carbonate. At the same time, two traditional methods of taking high-quality calcium carbonate as raw material were improved.Take high-quality calcium carbonate as raw material, (1) when adopting the direct approach, the optimum technology condition of refining is, regulating pH to 12 by bicomponent together, refining for 20 minutes, the condition of carbonization is, allowing 10% for ammonium bicarbonate, 15 minutes, 20 °C. the condition of washing is, 80 °C, ration of the amount of water and filter cake is 10. (2) when adopting the circulating method, the best technology condition of calcinations is 850 °C, the condition of maceration reaction of CaO(caldum oxide) and NH4CI (ammonium chloride) is 90℃ and 40 minutes, the other technology condition are the same as the direct approach.When taking industrial calcium nitrate as the raw material to prepare high-purity calcium carbonate, the optimum technology condition of refining is, regulating pH to 12 by bicomponent together, 20 minutes, the condition of carbonization is, allowing 20% for ammonium bicarbonate, 25 minutes and 30 °C. the condition of washing is, 20°C, ration of the amount of water and filter cake isAnalytical results indicate that the particle diameter of product range from 0.5 to 1.0 micrometer, the content of magnesium, iron, manganese, sodium, chlorine are 0.0016%, 0.0001%, 0.0001%, 0.0011%, 0.0005% respectively. The product is according with the standard of the enterprises well.Three kinds of technologies have themselves characteristics, particularly, the application foreground of the technology that taking industrial calcium nitrate as raw material is broad and worth popularizing. The innovation of study are following, it was put forward firstly that the industrial calcium nitrate was used as the raw material to prepare high-purity calcium carbonate, and a new proposal regulating pH by NH3 ? H2O (ammonia water) and a little amount Ca(OH)2 (calcium hydroxide) was introduced.