Cadmium Incorporation in the Crystallization of Calcium Sulfate Hemihydrate from Phosphoric Acid

✍ Scribed by T. T. Tjioe; H. Der Van Woude; J. Verbiest; P. F. M. Durville; G. M. van Rosmalen

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 691 KB
• Volume: 21
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.2170211009

✦ Synopsis

Semi-batch crystallization experiments of CaSO, -1/2 H,O (HH) wcre performed in concentratcd phosphoric acid at various H,SO, contents in the absence and presence of additives.

The influence of the operating conditions and additives on the cadmium and phosphate incorporation in the HH lattice were determined. The Cd uptake increased with raising H,SO, content. Addition of HNO, caused a reduced cadmium and phosphate incorporation.

Addition of iodide also lowered the cadmium incorporation.

The obtained results fits into a model for the incorporation of foreign ions during crystal growth. According to this model the incorporation is primarily a kinetically controlled process.