贵州清镇地区高硫型铝土矿预焙烧溶出性能研究

Digestion Performance of the Roasted Ore from Pre-roasting of Guizhou High-sulfur Bauxite

采用马弗炉焙烧处理贵州清镇地区某高硫型铝土矿并研究了焙烧精矿的溶出性能。结果表明:当焙烧温度700℃,焙烧时间30min时,矿石全硫含量从0.97%下降至0.21%,降低了78%,焙烧精矿含硫量达到拜耳法工艺要求;最佳溶出条件为:溶出温度260℃,苛性碱浓度190.32g/L,溶出时间60min,石灰添加量12%,固含300g/L,此时精矿实际溶出率82.45%,相对溶出率96.26%,分别比原矿直接溶出高4.28个百分点和4.85个百分点;精矿溶出赤泥A/S为1.22,N/S为0.25,分别比原矿直接溶出低0.29和0.09,整体溶出性能优于原矿。

The high-sulfur bauxite from Qingzhen Region in Guizhou Province was roasted in a muffle furnace and the roasted ore obtained was used in the test for investigating the digestion performance. It was found that after the bauxite being roasted at temperature of 700 ℃ for 30 min, the total sulfur content decreased by 78%, from 0.97% to 0.21%, resulting in the sulfur content in the concentrate up to the requirements of the Bayer process. Then the optimum conditions for digestion was decided as follows： temperature at 260 ℃, caustic sodium concentration at 190.32 g/L, digestion time of 60 min, lime addition of 12%, solid content of 300 g/L. Under such conditions, the practical digestion rate of alumina of the roasted ore was 82.45%, with relative digestion rate at 96.26%, 4.28 percentage point and 4.85 percentage point higher, respectively, compared to the raw ore. A/S and N/S of red mud of roasted ore is 1.22 and 0.25,with a reduction of 0.29 and 0.09 respectively, compared to red mud directed from raw ore, indicating the digestion performance of the roasted ore is better than that of raw ore.