摘要
水溶开采的硫酸钙型卤水中除主要含氯化钠外,还含有大量的钙和硫酸根离子,这不仅影响真空盐产品的纯度,同时在真空蒸发罐及卤水回用过程的管道输送过程中结垢严重,对生产过程影响较大。实验测定了硫酸钙型卤水中硫酸钙的溶解度曲线。采用十二烷基苯磺酸钠,重铬酸钾和聚乙二醇作为添加剂,研究了添加剂对硫酸钙型卤水体系中CaSO4.2H2O结晶动力学的影响。结果表明:重铬酸钾的加入量为150 mg/kg～250 mg/kg时,其促进CaSO4.2H2O晶体生长,当重铬酸钾的添加量为210 mg/kg时,其对CaSO4.2H2O晶体生长促进作用最明显,此时线生长速率为9.333×10-10 m/s;聚乙二醇作为添加剂在较大范围内都会对CaSO4.2H2O结晶过程起较为明显的促进作用,开始随着添加量的增加,得到的CaSO4.2H2O晶体产品的粒径将随之增大。当添加量为400 mg/kg时线生长速率达到最大值,为2.057×10-9m/s;十二烷基苯磺酸钠的添加浓度小于300 mg/kg时,其促进石膏型卤水体系CaSO4.2H2O晶体的生长。当添加量为30 mg/kg时,CaSO4.2H2O晶体的粒径达到最大值,此时的线生长速率为1.290×10-9 m/s。
Lots of Ca^2＋ and SO4^2- are exist in the brine of plaster brine system in spite of Na^＋ and Cl^- , calcium sulfate dehydrate has a great effect on the purity of sodium chloride product in the process of vacuum evaporation, CaSO4 · 2H2O will crystallized on the wall of pipes at the same time, which influence the production process much. In this paper, solubility of calcium sulfate dihydrate in gypsum type brine system was developed. Potassium dichromate, PEG and SDBS were chosen as additives to study the crystallization kinetics of calcium sulfate dehydrate in gypsum type brine system. The results showed that line growth rate was promoted when the concentration of potassium dichromate was between 150 mg/kg and 250 mg/kg. The line growth rate of calcium sulfate dehydrate reached 9.333×10-10 m/s when the concentration potassium dichromate was 210 mg/kg. PEG has an obvious effect on promoting the line growth rate of calcium sulfate dehydrate, it reached 2.057×10-9m/s when the concentration of PEG was 400 mg/kg, after that, it decreased with increasing the concentration of PEG. The line growth rate of calcium sulfate dehydrate increased when the concentration of SDBS was less than 300 mg/kg, the line growth rate was 1.290×10-9 m/s when the concentration of SDBS was 30 mg/kg.
出处
《盐业与化工》
CAS
2011年第2期15-18,共4页
Jounral of Salt and Chemical Industry
关键词
石膏型卤水
二水硫酸钙
添加剂
结晶动力学
晶体生长
gypsum type brine
calcium sulfate dehydrate
additives
crystallization kinetics
crystal growth
