Saponite clay tailing treatment by artificial sedimentation

摘要

Saponite amounts up to 95% of the clay tailings at a mineral extraction plant in Russia. Because of a very low rate of the saponite suspension precipitation and high porosity of the formed sediment (more than 90%) it was required to significantly intensify the sedimentation of the saponite tailings and to reduce the volume of the precipitated sediment. This paper particularly focused on the investigation of the effect of NaCl concentration and pH on coagulation of saponite suspensions, microstructure and properties of the formed sediments. By means of quantitative analysis of scanning electron microscope images we have managed to quantitatively describe the transformation of the saponite sediment microstructure with increase of NaCl concentration from 0.005 N to 0.5 N and pH from 2.5 to 8.5. A strong correlation has been found between the physico-chemical factors and the rheological properties of the clay tailings. It is the first time when the effect of the physico-chemical factors on the saponite colloidal properties has been extensively studied. Until now most of the investigations were done with kaolinite, illite and montmorillonite.