Study on the Thixotropy of Mineral Dispersions

At present, there is no national standard method to regulate the test method of thixotropy. The light industry standard of QB/T 1545-1992 is still available to test the thixotropy of nonmetallic mineral materials. The test method of thixotropy introduced in QB/T 1545-1992 is simple and has no detailed description and research on effect factors, such as the added amount of electrolyte and it is not precise enough to test thixotropy. In this research, the method of thixotropy and its affecting factors, especially the best added amount of electrolyte and the assembly time were studied by testing the thixotropy of three kinds of bentonite samples and one kind of saponite according to the standard of QB/T 1545-1992. It was found that there was a great impact of added electrolyte on the thixotropy. Different kinds of minerals, even different samples of the same kind of mineral have different optical amounts of electrolyte added into the mineral dispersions. Hereby, the optical amount of electrolyte should be tested for each sample. It was also found that the assembly time of the mineral dispersion has a great effect on thixotropy. The assembly time of 10 to 12 hours should be strictly adhered to, followed by the standard method of QB/T 1545-1992 to obtain good precision. The longer assembly time will increase thixotropy significantly, which cannot be calculated. The method of testing thixotropy and its affecting factors, in order to provide the basis for improvement for existing thixotropy test method are the main focus of this work.