Economou Evangelos D, Vaimakis Tiberius C, Papamichael Emmanuel M
Department of Chemistry, University of Ioannina, P.O. Box 1186, Ioannina, 45110, Greece.
J Colloid Interface Sci. 2002 Jan 1;245(1):133-41. doi: 10.1006/jcis.2001.7931.
In this manuscript we present, in detail, the mechanism of the selective dissolution of calcite from low-grade phosphate ores (Epirus area, Greece) by dilute acetic acid. It was found that mass transfer makes a significant contribution to the rate-determining step of the overall reaction of four separate pH regions discriminated within the pH range from 3.96 to 6.40. Moreover, two different reaction mechanisms were proposed and two different model equations best fitted the corresponding experimental data. By applying a particular treatment to the developed differential equations proposed by us earlier (see Ref. (2)), we estimated the rate constants of specific slow reactions referred to pH regions 3.96-4.95 and 4.95-5.50. However, for pH region 5.50-6.40, we cannot reach a similar conclusion so far.
在本论文中，我们详细阐述了稀醋酸从低品位磷矿石（希腊伊庇鲁斯地区）中选择性溶解方解石的机制。研究发现，在pH值3.96至6.40范围内区分出的四个不同pH区域中，传质对整个反应的速率决定步骤有显著贡献。此外，提出了两种不同的反应机制，且两个不同的模型方程最符合相应的实验数据。通过对我们之前提出的微分方程进行特定处理（见参考文献(2)），我们估算了pH值区域3.96 - 4.95和4.95 - 5.50中特定慢反应的速率常数。然而，对于pH值区域5.50 - 6.40，目前我们还无法得出类似结论。
