Wollastonite is a kind of chain metasilicate, which is generally fibrous and needle-shaped. Due to its special crystal morphology and crystal structure, its properties are determined. Wollastonite has good insulation properties, high whiteness, good dielectric properties, and high heat and weather resistance. Because wollastonite is widely used in ceramics, chemical industry, metallurgy, papermaking, plastics, coatings and other fields.
Processing of Wollastonite
The main methods of wollastonite beneficiation at home and abroad are manual, single magnetic, flotation, and magnetic-flotation (or electric) combined processes. The main purpose of beneficiation is to reduce iron content and separate calcite.
(1) Hand selection
The mining site manually selects rich ore blocks or crushes them on the conveyor belt to manually select wollastonite rich ore blocks. Manual selection is suitable for better quality ore.
(2) Single magnetic separation
The main associated minerals in wollastonite rocks, such as diopside and garnet, are weak magnetic minerals, while wollastonite basically does not show magnetic properties, so dry or wet strong magnetic separation technology can be used to make wollastonite interact with it. Separation can separate a lot of iron-containing minerals and improve product purity.
(3) Single flotation
According to the difference in the physicochemical properties of the wollastonite and calcite mineral surfaces, the flotation method can effectively separate them from each other, thereby improving the purity of the wollastonite product.
(4) Magnetic separation-flotation combined process
This method is suitable for the treatment of low-grade wollastonite. First, dry or wet magnetic separation is used to separate weak magnetic minerals. Flotation is then used to separate wollastonite from minerals such as calcite and quartz. Flotation separates wollastonite and calcite. There are two main processes for minerals such as quartz.
① Reverse flotation scheme of anion collector
Calcite is a carbonate mineral, wollastonite and quartz are both silicate minerals. Based on this, according to the difference in surface electrical properties of the two, by adjusting the pH value of the pulp medium, adjusting agents are used to suppress wollastonite and floatation separation. Calcite. Flotation then separates the quartz and wollastonite. Oxidized paraffin soap is generally used as the calcite collector, and sodium silicate is used as the inhibitor of wollastonite and quartz.
② Positive flotation scheme of cationic collector
This method mainly adjusts the surface electrical properties of wollastonite and calcite minerals to make them have different potentials, so that cationic collectors preferentially float out wollastonite through electrostatic adsorption, while calcite is left in the float as tailings. Select slot. The flotation operation is divided into two stages: the first stage uses amine collectors to float wollastonite and silicate minerals as foam products, while the calcite stays in the tank; the second stage uses amine ions and anions to capture the mixture The collector performs flotation of silicate impurities, while wollastonite is recovered as a product in the tank.
(2) Crushing and processing of acicular wollastonite
Wollastonite powder is a short fibrous inorganic powder. In some application fields, such as ceramics, glass-ceramics, metallurgical protective slag, etc., only for asbestos substitutes, paper and pulp substitutes, plastic and rubber reinforcing fillers, and some coating fillers, etc. It is required, and the aspect ratio of the fibrous particles is also required. High aspect ratio (> 10) wollastonite powder can replace asbestos fibers, papermaking fibers, and advanced reinforcing fillers of polymer-based composites such as plastics and rubber, etc., and has great application and economic value. therefore. The processing technology of wollastonite acicular powder with high aspect ratio is one of the main deep processing technologies of wollastonite.