关键词: 白云岩, 氢氧化镁, 氨化, 清洁生产

Abstract:

The dolomite powder, sampled from Huangyue valley, Lushi County of Henan Province, was dissolved using hydrochloric acid to obtain the solution of MgCl₂ and CaCl₂. The iron and aluminium cations in the solution were removed by adjusting its pH to 6-7. The lightweight magnesium oxide and calcium carbonate were prepared using the purified solution by ammonification, aging and carbonization. This study mainly investigates the effect of ammonification temperature(time) and the aging temperature(time) on the ratio of Mg²⁺ precipitation, and the effect of carbonization time on the crystal form of calcium carbonate. Scanning electron microscope (SEM) and chemical analysis methods were used to characterize the products. The lightweight magnesium oxide obtained is platelet in form with the average particle size of 150 nm, and matches the chemical industry standard HG/T2573—2006. The light-weight calcium carbonate obtained is sphere in form with the average particle size of 100 nm, and matches the chemical industry standard HG/T2567—1994. The presented technique which is characterized by low energy consumption and high utilization ratio, is a potential environmental friendly way for the clean processing of dolomite ores.

Key words: dolomite, magnesium hydroxide, ammonification, clean processing