氧氯化锆生产中转型料酸解与絮凝脱硅过程

Acid Decomposition and Desilication by Flocculation of Transformation Mass in Production of Zirconium Oxychloride

以锆英石碱分解所得烧结料经水洗、转型后的转型料为原料,研究其盐酸酸解与酸解液絮凝脱硅过程中主要工艺参数对脱硅效果的影响,并采用红外与核磁共振表征水洗料转型、转型料酸解及酸解液絮凝过程中硅酸聚合状态.实验获得优化的酸解与絮凝条件为:酸解温度微沸,酸解时间5 h,酸解酸度5.20 mol/L(以HCl计),锆液浓度125 g/L[以Zr(Hf)O2计],絮凝温度40℃,絮凝时间1 h,絮凝剂为阳离子聚丙烯酰胺类CPAM-1,絮凝剂浓度1%(ω),加入量4%(φ).在该条件下进行5 L规模实验,氧氯化锆水溶液硅含量稳定降至(35～50)×10-6(ω),锆含量及酸度分别为120 g/L[以Zr(Hf)O2计]和5.10 mol/L(以HCl计),由该水溶液蒸发浓缩结晶所得氧氯化锆产品指标与市售普通级产品相当.

The transformation mass from water and acid washing of zircon-NaOH fused material was used as raw material for acid decomposition. The effects of main parameters in acid decomposition and flocculation processes on removal of silicon were studied. The polymerization state of silicic acid in the transformation, acid decomposition and flocculation was characterized by both IR and NMR. The optimal conditions of acid decomposition were obtained： temperature at boiling point, time of 5 h, acidity of 5.20 mol/L （calculated by HC1） and Zr（Hf）O2 concentration of 125 g/L. The cationic polyacrylamide labeled with CPAM-1 was adopted as flocculant, its concentration was 1%（co）, and added volume 4%. The turbid zirconium oxychloride solution obtained by acid decomposition was treated by CPAM- 1 at 40 ℃ for 1 h. The 5 L scale-up experiment was carried out at the above conditions, and the zirconium oxychloride solution after purification contained （35-50）×10^-6（ω） of silica. The quality and properties of obtained zirconium oxychloride product in specifications were equivalent to those of conventional commercial product.