Feldspar crushing scheme
Feldspar is an aluminosilicate mineral of alkali metal or alkaline earth metal such as potassium, sodium, calcium and barium. The main components are silica, alumina, potassium oxide, sodium oxide and calcium oxide. The Mohs hardness is 6.0-6.5, and the relative density is 2.55-2.75g/cm3. Pure feldspar is rarely found in nature.
Purpose of finished product:
Most of feldspar minerals are used as industrial raw materials, accounting for 30% in the ceramic industry, and the rest are used in other industries such as chemical industry, abrasive grinding tools, glass fiber, welding electrodes, etc. the fineness of feldspar powder varies with the grinding machine used in operation, and the use is also different.
1. Glass flux
Feldspar is one of the main components of glass mixture. Feldspar has high alumina content, low iron content and is more fusible than alumina. It not only reduces the melting temperature, but also increases the alkali content to reduce the amount of alkali. In addition, the melting process of feldspar into glass is relatively slow, and the crystallization ability is small, which can prevent the precipitation of crystals in the process of glass formation and damage products; feldspar can also be used to adjust the viscosity of glass.
2. Proportioning of ceramic body
Before firing, feldspar can act as barren raw material, reduce drying shrinkage and deformation of green body, improve drying performance and shorten drying time. During sintering, it can be used as a flux to reduce the sintering temperature, promote the melting of quartz and kaolin, and diffuse and permeate each other in the liquid phase, thus accelerating the formation of mullite. The feldspar glass formed in the melting process fills the mullite grains of the green body, which makes the body compact and reduces the voids, thus improving its mechanical strength and dielectric properties. In addition, the formation of feldspar glass can improve the transparency of green body.
3. Ceramic glaze
The ceramic glaze is mainly composed of feldspar, quartz and clay, and the feldspar content can reach 10-35%. In the ceramic industry, potash feldspar is the main raw material and glaze.
4. Enamel raw materials
It is mainly composed of feldspar and other mineral materials. The amount of feldspar is usually 20-30%.
Potash feldspar can be used as raw material for extracting potash fertilizer.
Feldspar has the characteristics of low melting point, long melting time, high viscosity of molten liquid and transparency of glassy material formed by melting at high temperature. Alkali feldspar can reduce glass melting temperature and save soda ash. It is also the main raw material for producing various ceramic, enamel and electric porcelain blanks and glazes. In recent years, with the development of color glass shell and ultra-high voltage electric porcelain industry, as well as the increasingly high-grade of daily-use ceramics, the demand for high-purity low-iron alkali feldspar is increasing. Due to resource constraints, high-quality alkali feldspar is in short supply. There are abundant alkali feldspar resources in China, but there are not many high-quality ores. Most of the ores need iron removal to meet the quality requirements of industrial production. Therefore, the beneficiation and iron removal process of feldspar is highly valued by enterprises.
1. High grade alkali feldspar produced by pegmatite
The roller mill used in this process has low grinding efficiency, small processing capacity, less high-grade feldspar, and the product price is constantly increasing. Because there is no iron removal process in this process, the products can not meet the requirements of ceramic and color glass shell factories, the production technology is backward, the quality is low, and the economic benefits are declining.
2. Alkali feldspar in weathered granite
Crushing → grinding → classification → flotation (except iron, mica and quartz) → pressure filtration → drying → finished products. Although the alkali feldspar produced by this process can meet the product quality requirements of ceramic and color glass shell factories, it is not recommended to adopt this process because of its high beneficiation cost and environmental pollution.
3. Alkali feldspar in fine crystalline rocks
Crushing → grinding → screening → magnetic separation → pressure filtration → drying → finished products. This process adopts wet production, which can meet the quality requirements of high-grade ceramics and color glass shells. The process is complex and needs pressure filtration and drying equipment. The production cost is too high, so it is not recommended to use this process.