Cleavage Fracture Of Mica And Its Application In Pearlescent Pigment

Sericite is a kind of natural inorganic material. In our country there is a abundant of this resource. Mica has the excellent properties of electrical insulation, heat resistance, water resistance, chemical corrosion resistance and high cleavage. Those properties of sericite may not be substituted by other mineral resource. At present, the domestic level of sericite processing is lower. The most products are primary or secondary products. With the development of material science those can't satisfied with the quality requirement. As a functional material or filling there is the need of higher content whiteness and aspect ratio. Then, mica pearlescent pigments are now more and more widely used as they endow objects with deeply three-dimensional space character by means of sunlight irradiation together with their other excellent capabilities, such as chemical resistance, abundance of color and innocuity. It still exists many problems. For example, the pearlescent luster is faint, the color is not pure and the wetting performance and disperse capability is not good enough. These producers in China are also face the same difficulty in manufacture. Also, mica resource is decreasing quickly with increasing use. Using sericite to substitute mica becomes more and more important.The cleavage fracture results showed that: by changing the cleavage fracture mode, stirring speed, sericite mineral materials can be possessed to different quality mica products. The cleavage fracture process of can be obtained through attrition and shearing. In this study, the brighter sericite with aspect ratio over 80 was obtained by adding a certain viscosity of polymer materials in aqueous solution. By acid treatment, the whiteness was over 75.The preparation of the optimum mica pearlescent pigments was sure the mastering of the various crafts of the influence factors. Fistly, mica with acid pretreatment enhance the whiteness before plating mica, secondly, in particular, in the critical craft of the plating ,we found the optical parameter of this craft were that the pH value was between 2 and 2.5, the reaction temperature is 80℃,the titanium salinity is 15%,stirring rate was 250-300r/min, hydrolitic reaction time was 3.5h,and the optimum factors which influence the whiteness and luster of the final production are calcining at 800℃for 2h.In this paper, sericite cleavage fracture and the preparation of pearlescent pigments pilot were studied, and we also discussed the mechanism of the sericite cleavage fracture and the deposit procedure of mica pearlescent pigments, which will play part in developing sericite application in our national and economic development.