Precipitation of fine single crystal of sparingly soluble salt

微溶盐的细单晶沉淀

基本信息

批准号：
63550716
负责人：
TOYOKURA Ken
金额：
$ 1.41万
依托单位：
Waseda University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63550716/
关键词：
Sparingly soluble salts Precipitation Lead sulfate Decreasing rate of concentration Crystal size distribution CDJ crystallizer 回分式単結晶群微粒子

项目摘要

Precipitaion tests of lead sulfate in a solution obtained by reaction between lead nitrate solution and sulfuric acid, were carried out in a batch agitated vessel at 308K, and a correlation between a decreasing rate of a concentration of lead ion and a size distribution of lead sulfate crystals grown, was studied. A relatively uniform size crystal was obtained in the supersaturated solution whose concentration decreased on the rate proportional to a supersaturation. On these tests, the solutions prepared separately, were mixed at one time and a uniformity of size distribution was affected by a mixing condition on initial stage of feed. On some tests, a size distribution became broad.Other tests were also done in the CDJ (Controlled Double-Jet) crystallizer of two liters on volume which was devised to make two solutions mixed well. On these tests, an aqueous solution of lead nitrate or sodium sulfate was separately fed into an mixed gelatin solution in the crystallizer through an individual pipe, and reacted. In order to obtain homogeneous desired size crystals, these tests was batchwisely carried out in the operation whose conditions were selected to make nucleation occurred on an initial stage and finished in a short period. On the following step, born nuclei were expected to grow to a desired size crystals without nucleation. The main operational conditions were as following : Concentration of feed solution of lead nitrate or sodium sulfate was 0.10mol/l, respectively. Feed rates of solutions were 10ml/min, the concentration of acetic acid and gelatin in a mixed solution in the crystallizer were 1.74x10^<-1>mol/l, and 2wt%, on initial stage. An excess concentration of operating solution was 2 or 3, on pPb or PS04, and lozenge- shape crystals whose average size and coefficient of valience were 4.5um and about 15 percent, were obtained on the operational condition of 2 on the excess of pPb.

通过硝酸铅溶液和硫酸之间的反应获得的溶液中的沉淀测试在308K的批处理搅拌容器中进行，并研究了铅离子浓度的降低速率与铅硫酸盐晶体种植的大小分布之间的相关性。在过饱和溶液中获得了相对均匀的尺寸晶体，该溶液的浓度与过饱和成比例的速度降低。在这些测试中，分别制备的溶液一次混合，尺寸分布的均匀性受到饲料初始阶段的混合条件的影响。在某些测试中，尺寸分布变得宽广。其他测试也在CDJ（受控的双喷射）结晶器中进行了两升的体积，该结晶器设计为使两种溶液充分混合。在这些测试中，通过单个管道将硝酸铅或硫酸钠的水溶液分别喂入结晶剂中的混合明胶溶液中，并反应。为了获得均匀的所需尺寸晶体，这些测试是在操作中进行批处理进行的，该操作选择了条件以使成核发生在初始阶段，并在短时间内完成。在接下来的一步中，预计出生的核将生长到所需的尺寸晶体，而无需成核。主要操作条件如下：硝酸铅或硫酸钠的进料溶液的浓度分别为0.10mol/L。溶液的进料速率为10ml/min，在结晶剂中混合溶液中乙酸和明胶的浓度为1.74x10^<-1> mol/l，在初始阶段为2wt％。在PPB或PS04上，过量的操作溶液浓度为2或3，在PPB过量的PPB中，获得了2.5UM的平均大小和价值晶体，其平均尺寸和价值为4.5UM和约15％。