Reactions of calcite in water in the presence of stearic acid

Abstract

In the suspension of water and calcite, with pH 10.14, on the border of calcite / water was formed a double electric layer. Its structure, or hydrophilic properties of minerals, depended on the concentration of potential determination ions, Ca2+ i 2 CO3 , pH of the environment, and the adsorption of water molecules and ions (and molecules), formed in a suspension of calcite as a result of its solubility in alkaline media. The structure of such a way formed electrical double layer, influenced on interaction of minerals with stearic acid as a surface of active substance. In the presence of stearic acid, the pH value of slurry decreased to 8.72 due to the dissociation of stearic acid in alkaline medium and reaction of neutralization. As the result of dissociation, in the suspension, besides the un-dissociated acid molecules, there were also stearine ions CH3(CH2)16COO-, (St-), which have reacted with the surface of minerals, transforming it from hydrophilic to hydrophobic.

Keywords

• calcite
• stearic acid
• solubility
• electric double leyer