| Muscovite is a kind of the layered hydrous aluminum silicate mineral, which is widely used in rubber and other fields with good physical and chemical properties. And it is one of minerals which are more difficult to grind. However, there are few processing factories and less technology to produce high quality products. It is difficult to meet the demand of the market for high-end product. Therefore, the different factors on ultra-fine grinding of muscovite were researched through using muscovite produced by Henan province as the main raw materials. The process parameters were optimized and the grinding mechanism was analyzed for ultra-fine grinding of muscovite. Then,the industrial test was done based on the research results.Single factor experiment showed that particle size of muscovite was smaller with the increase of milling time, and the best muscovite slurry concentration of grinding was 45%. It’s good for ultra-fine grinding of muscovite through improving the mixing mill speed and reducing the proportion of material and grinding ball. And the best gradation was 3:5:2 for 4~5 mm, 3~4 mm and 2~3 mm ceramic balls, respectively.Sodium tripolyphosphate and triethanolamine were in favor of grinding and the optimum contents were 1‰ and 0.2‰, respectively.The orthogonal experiment showed that the effects of grinding time and agitation speed on the ultra-fine grinding size of muscovite and specific surface area were highly conspicuous. The particle size of 82.6% superfine muscovite obtained was less than 13μm when the processes were grinding under the condition of 75 min, 600 r/min ofagitation speed, 0.02 % sodium tripolyphosphate in the muscovite, 3:5:2 for 4~5 mm,3~4 mm and 2~3 mm ceramic balls, respectively.Grinding experiment of ultrafine muscovite of industrial was carried out. The results showed that the particle size of 58.01% superfine muscovite obtained was less than 13μm under the condition of the feed amount of 0.39 t/h, 9.25 t of ceramic balls,48.5%-49.5% of feed concentration, 2.5‰ sodium tripolyphosphate in the muscovite,161r/min of agitation speed, 4:2:3 for 2~2.5 mm, 2.5~3 mm and 3~3.5 mm ceramic balls, respectively. The superfine grinding products were classified by cyclone with good classification effect. The flow sheet of preparation of ultra-fine powder of muscovite for industrial process was recommended.In this paper, muscovite superfine grinding process and grinding mechanism of the sodium hexametaphosphate and triethanolamine were studied by using the methods of SEM, XRD, and so on. The results showed that the crystal of muscovite ultrafine grinding was destroyed given priority to intergranularly firstly, and then destroyed given priority to transgranularly after 2.5h. The lattice ordered structure gradually collapsed with appearance of pulverization. As grinding agent, it can improve grinding effect by adsorbing of phosphate ions of sodium hexametaphosphate on white mica particles surface, with improving the dispersion and reducing the surface energy of crystal, the lattice of crystallinity and slurry viscosity. As muscovite surface was adsorbed by-NH2and-OH of triethanolamine molecular, grain stress defect or lattice defects were produced by increasing crystal plane spacing, reducing bond energy of surface,increasing lattice strain, and it’s easy to broken for muscovite particles. At the same time, new cracked valence of crystal face was neutralized by triethanolamine to improve the dispersion of mica powder. Thus, it’s improving grinding efficiency. |
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