| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1989: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1988: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
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.
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