Dissolution in Plural Minerals-Water System and Its Effects on Interfacial Phenomena and Flotation of Each Mineral

盐型矿物如萤石、方解石、氟碳铈矿在水中溶解度较高。当盐类矿物共存时，它们所衍生的离子对彼此的表面性质和浮选性能有明显的影响。本研究采用自行研制的特殊仪器和方法，对混合矿物体系中发生的现象进行了研究。主要结果如下：（1）所有结果（浮选，zeta电位等）。在萤石和方解石二元矿物系统中得到的结果与在单一矿物系统中得到的结果不同。这种差异是由两种矿物在水溶液中溶解的离子种类的影响造成的。这被解释在表面沉淀和/或矿物和溶解的离子物种之间的表面反应。化学热力学计算结果表明，当pH值低于8.3-9.3时，萤石相比方解石相更稳定，此时二元矿物体系中的方解石表面变得与萤石相似。在此pH范围以上，观察到相反的现象。(2)N-油酰肌氨酸、十八烷基硫酸钠和N-牛脂-1，3-丙二胺二油酸酯（TDO）选择性地与盐类矿物的组成离子反应，这些表面活性剂可作为氟碳铈矿、独居石、萤石、重晶石和方解石的捕收剂。高浮选回收率的pH值范围内，TDO是目前作为反离子，并提出了一个可能的解释，其吸附在盐型矿物。(3)由于TDO不与浮选矿浆中的主要离子发生反应，因此TDO是盐类矿物优先浮选的有效捕收剂。

Salt-type minerals such as fluorite, calcite and bastnaesite have higher solubilities in water. When salt-type minerals coexist, the ions derived from these minerals markedly affect the surface and flotation properties of each other. In this study, special apparatus and methods developed by the authors were used to investigate the phenomena occurring in the mixed minerals system. The main results were as follows: (1) All results(flotation, zeta potential, etc.) obtained in the binary minerals system of fluorite and calcite differed from those in the singular mineral systems. The difference was caused by the effect of the ionic species dissolved from both minerals in the aqueous solution. This was interpreted in terms of the surface precipitation and/or surface reaction between both minerals and the dissolved ionic species. The results of chemical thermodynamic calculations showed that the fluorite phase was more stable than the calcite phase below pH 8.3-9.3, where the calcite surface in the binary minerals system became similar to that of fluorite. Above this pH range, the reverse phenomenon was observed. (2) N-oleoylsarcosine, sodium octadecylsulfate and n-tallow-1,3-diaminopropane dioleate(TDO) reacted selective- ly with the constituent ions of salt-type minerals, and these surfactants can be used as collector in flotation of bastnaesite, monazite, fluorite, barite and calcite. High flotation recovery was obtained in the pH range where TDO is present as ampho-ion, and a possible explanation for its adsorption on salt-type minerals was presented. (3) Because TDO did not react with main ions in flotation pulp, TDO was an effective collector for selective flotation of salt-type minerals.