高碳铝土矿焙烧预处理及焙烧矿的溶出试验研究

Roasting pretreatment of high-carbon bauxite and Bayer digestion tests of the roasted ore

对高碳铝土矿进行了焙烧预处理和溶出试验研究。试验结果表明:在温度600℃条件下焙烧20min,焙烧矿中的总碳含量可降低至0.064%,总碳的脱除率可达到97.17%;矿石中几乎全部的硫保留在焙烧矿中,焙烧过程不增加烟气中SO2排放。在溶出温度260℃、石灰添加量10%及溶出液αK 1.40左右的条件下,焙烧矿的溶出效果良好:氧化铝溶出率达到76.77%,溶出赤泥A/S 1.22,溶出赤泥N/S 0.52。在焙烧矿溶出过程中,矿石中的硫绝大多数进入赤泥,仅有不到5%进入溶液,焙烧矿中的硫对氧化铝生产过程影响不大。

Experiments on the roasting pretreatment of high-carbon bauxite and Bayer digestion tests of roasted ore were carried out.The test results show that,the total carbon content in the roasted ore can be decreased to 0.064%after being roasted for 20 minutes at 600℃,and the removal efficiency of total carbon contained in the raw bauxite can reach 97.17%.Almost all the sulfur contained in the raw bauxite remains in the roasted ore and the emission of sulfur dioxide in exhuast gas will not be increased during roasting process.The Bayer digestion results of the roasted ore is satisfactory when which is digested at 260℃for 50 minutes with theαK of about 1.40 in digested liquor and lime addition 10%,and the digestion efficiency of alumina from the roasted ore can reach 76.77%,and the A/S of red mud is 1.22,the N/S of red mud is 0.52.Most of the sulfur in the roasted ore still remains in the red mud,and the proportion of sulfur that enters into solution during Bayer digestion is lower than 5%,thus,the sulfur remained in the roasted ore will have little effect on the alumina production process.