(NH4)2SO4溶液中CaSO4·2H2O溶解速率增长特性及机制  

The characteristics and mechanism of CaSO4· 2H2O dissolution rate increased in （NH4）2SO4 solution

作　　者：刘仕忠[1] 朱家骅[1] 夏素兰[1] 葛敬[1] LIU Shizhong;ZHU Jiahua;XIA Sulan;GE Jing(School of Chemical Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学化学工程学院

出　　处：《磷肥与复肥》2020年第1期4-7,10,共5页Phosphate & Compound Fertilizer

基　　金：国家科技支撑计划课题(2013BAC12B01)

摘　　要：以石膏块材为研究对象,在温度(25℃)、搅拌转速(180 r/min)恒定的条件下,通过电感耦合等离子体原子发射光谱法(ICP-AES)测量溶出钙离子的浓度,对不同浓度硫酸铵溶液中Ca SO4·2H2O的溶解速率进行研究。结果表明,在Ca SO4·2H2O溶解度以及溶液黏度的共同影响下,随着硫酸铵溶液浓度的增加,Ca SO4·2H2O的溶解速率先减慢后显著增加并超过其在纯水中的溶解速率。当硫酸铵浓度为2.50 mol/L时,二水硫酸钙的平均溶解速率达到纯水中的2倍。Ca^2+浓度小于94%Ca SO4·2H2O溶解度时,Ca SO4·2H2O在硫酸铵溶液中的溶解反应为一级反应,且在0、0.01、0.07、0.53、1.50、2.50 mol/L硫酸铵溶液中的溶解速率常数k分别为2.923×10^-5、2.921×10^-5、2.805×10^-5、2.573×10^-5、2.134×10^-5、1.993×10^-5m/s。Taking calcium sulphate dihydrate block material as subject, the concentration of calcium ions and the dissolution rate of CaSO4· 2H2O in different concentration of ammonium sulfate solution are studied by ICP-AES under constant temperature(25 ℃) and stirring speed(180 r/min). The results show that under the influence of CaSO4· 2H2O solubility and solution viscosity, the dissolution rate of CaSO4· 2H2O decreases first and then increases significantly and exceeds the dissolution rate in pure water with the increase of the concentration of ammonium sulfate solution. The average dissolution rate of calcium sulfate dihydrate is twice of that of pure water at ammonium sulfate concentration of 2.5 mol/L. When the molar concentration of Ca^2+is less than 94% of solubility of CaSO4· 2H2O, thedissolutionreactionofCaSO4· 2H2Oinammoniumsulfatesolutionisafirst-orderreaction.And thedissolutionrateconstant k is 2.923×10^-5,2.921×10^-5,2.805×10^-5,2.573 ×10^-5,2.134×10^-5,1.993×10^-5 m/s in0, 0.01, 0.07, 0.53, 1.50, 2.50 mol/Lammoniumsulfate solution respectively.

关 键 词：二水硫酸钙 硫酸铵 溶解度 速率常数 黏度 

分 类 号：TQ132.32[化学工程—无机化工]