Preparation technology of barite powder
Barite is the most common mineral. Its composition is barium sulfate ( BaSO4 ), which can be produced in low-temperature hydrothermal veins and sedimentary rocks. The chemical composition includes 65.7% BaO and 34.3% SO3 , and there are similar substitutions of Sr, Pb and Ca in the composition. Barite is usually plate-like, granular, fibrous aggregates and crystal clusters of plate-like crystals, a few of which are dense, massive, cryptocrystalline, and soil-like, and stalactites and nodules with concentric belt-like structures are also seen. .
The pure barite is colorless and transparent, generally white, gray, light yellow, light brown, and may be light blue, pink, dark gray, etc. with impurities. Glass luster, transparent to translucent, low abrasion, good shielding, can absorb X-rays and Y-rays, chemically stable, and pure ones are hard to dissolve in water and acid.
The world is rich in barite resources, with reserves of 2 billion tons. World-famous barite producing areas include: Westmanland and Cumbria in the United Kingdom, Phils Bonny in Romania, Saxony in Germany, Tianzhu in Guizhou, China, Gongxi in Hunan, Liulin in Hubei, and Guangxi Heifenggou in Gansu, Xiangzhou, Shuiping in Shaanxi, etc.
Barite is divided into high-purity barite, ultra-fine barite, and ultra-fine active barite.
Preparation technology of high-purity barite powder
- Physical purification
Hand selection: According to the difference in color and density of barite and associated minerals, select blocky barite.
Gravity separation: According to the density difference between barite and associated minerals, the raw ore is screened, crushed, grading desliming, jigging, shaking table and other processes to obtain products with a grade of more than 88%.
Magnetic separation: It is often used to remove some iron oxide magnetic minerals and use it as the raw material of barite for collar-based drugs that require very low iron content.
- Chemical purification and whitening
Flotation: Barite with a small particle size is embedded, and physical removal of impurities is not good, and flotation is often used.
Chemical purification and whitening: through acid (or alkali) leaching, oxidation-reduction to remove carbon and iron, manganese, magnesium, nickel and other impurities in the ore.
Calcining and whitening: The hydrothermal barite undergoes heat absorption and blasting at high temperatures to volatilize the color-causing organic matter distributed in the barite crystals or gaps.
Preparation technology of ultra-fine barite powder
- Dry process
Jaw crusher, Raymond mill air classifier → baking oven → washing → dilute pickling → pulping → reaction kettle pickling reduction → filter press → washing → filter press → drying → crushing → packaging → product
- Wet process
Stirring mill, vibration mill, ball mill→modifier or precipitant→hydroxide or hydrated oxide→coating film→washing→drying→roasting→fixing→product
Preparation technology of ultrafine active barite powder
Surface chemical coating: modifier molecules are covered on the surface to obtain modified products.
Mechanochemical modification: Activate the particle surface, improve the activity of BaSO4 and other organic matter.
Encapsulation modification: The surface of the particles is covered with a homogeneous film with a certain thickness.
High-energy modification and acid-mechanical modification: use ultraviolet, infrared, corona discharge and plasma irradiation for surface treatment.
Application of barite powder
- Chemical raw materials
Reagents and catalysts, medicaments for mineral processing and paper production, additives for oils and fats, production of plastics, pesticides, herbicides, fungicides, production of various fireworks…
- Drilling mud
Barite is usually relatively pure, soft, relatively dense, chemically friendly, and inexpensive. 80-90% of its output is used as a weighting agent for drilling mud.
- Glass material
Barite is used in glass production to make the melt uniform and improve the brightness and transparency of the glass product.
- Chemical packing
Barite powder is a general industrial filler and a good brightening agent and weighting agent. Chemically bleached barite powder is a good white pigment.
- Other applications
Barite has good properties of absorbing Y radiation, so it can be used as a shielding material; it can also be used as a getter binder for vacuum tubes such as televisions.
The development trend of barite powder preparation technology
The main preparation technologies of barite-based mineral materials include ultra-fine and surface modification, but there are not many in-depth studies on the theoretical issues of barite ultra-fine processing, mechanochemistry, interface chemistry, doping modification and other processes. Traditional barite minerals are mainly used in low value-added fields such as petrochemicals, with low product utilization and low value.
We must transfer the traditional application of barite to how to combine the mineral composition, chemical composition structure, surface properties and other related characteristics, develop simple modification processes, study relatively inexpensive, non-toxic surface modifiers, and promote The development of barite processing, the comprehensive utilization of barite, and the improvement of the competitiveness of barite ore powder.
Article source: China Powder Network