Abstract:To address sudden deterioration of dissolution effect and sodium removal effect during alumina dissolution, experimental study on dissolution verification of bauxite from several main ore sites in Zunyi area was carried out. Under the conditions of conventional lime dosage of production, dissolution temperature of 265 ℃, dissolution time of 60 min and molecular ratio of 1.4, it is found that dissolution effect and sodium removal effect of predesilication bauxite No.1 and No.2 are very poor, but the situation can be significantly improved by greatly increasing lime dosage or by predesilication treatment for 14 h. The reason is that long time predesilication improves infiltration of alkali liquor into fine cracks of bauxite and contact extent between bauxite and lime, and also eliminates insufficient lime activity, which plays the same role as increasing lime dosage, and eliminates big influence of titanium impurities in bauxite on dissolution performance. It is suggested that predesilication process be added or strengthened during design and production of plant, which can effectively solve problem of mixed indissolvable bauxite and reduce consumption loss of caustic soda, bauxite and lime in production.