Barium Carbonate_Industrial Additive

Barium Carbonate [Background and Overview]

In recent years, the development of the domestic automobile and construction industries and the prosperity of the home appliance industry have driven the growth of magnetic materials, radio components and industrial sanitary ceramics, and the demand for barium carbonate has also increased. In industries such as automobiles, construction, industrial sanitary ceramics, magnetic materials, and radio components, the annual domestic demand is 30,000 to 40,000 tons. In my country, granular barium carbonate is widely used in the production of glass bulbs for color TV picture tubes. Because barium carbonate has strong X-ray and A-ray shielding capabilities, adding barium carbonate to the glass bulb can effectively absorb X-rays and A-rays generated by high-voltage current. To prevent its harm to human body. At present, the export price of barium carbonate in my country is about 30% lower than that in the international market. The main reason is that most of our products are general-purpose, and some physical and chemical indicators and product packaging forms are still far behind those of developed countries. For example, my country’s barium carbonate products have high purity, but high iron content and a certain amount of fluorine, which cannot meet the needs of some industries. The purity of barium carbonate used in the magnetic materials industry is only required to be 98%, but the product particle size must be small and uniform, otherwise the magnetic retention time will be shortened and the technical indicators will drop significantly. Barium carbonate is mainly used in the radio industry for capacitors, high-voltage ferroelectrics, etc. The purity and iron content play a decisive role in the product. In economically developed areas such as Europe and the United States, the brick-making industry has particularly low quality requirements for barium carbonate. A purity higher than 95% can meet the requirements. There are no requirements for indicators such as hydrochloric acid insoluble matter and sulfide of barium carbonate. In terms of high-purity barium carbonate, some high-end products are imported from Japan at very high prices. However, the current price of high-purity barium carbonate in my country is relatively low. We should improve the quality of high-purity products and occupy the market with high-quality and high-priced products. For foreign markets, we should pay attention to capturing foreign information, pay attention to the development and promotion of new technologies, new processes, new methods, and new equipment, focusing on improving product quality, saving energy, reducing consumption, reforming processes, and updating equipment, and pay attention to the introduction of technology digestion and absorption, strive to improve equipment levels, and make my country’s barium carbonate products develop in the direction of standardization, functionality, and specialization. In particular, the advent of large-screen color TVs and the popularization of computers have greatly promoted the development of barium carbonate.

Barium carbonate [Physical and chemical properties]

The chemical formula of barium carbonate is BaCO₃. Molecular weight 197.35. There are three configurations:

1) α type: white hexagonal crystal. Relative density 4.43, melting point 1740℃ (90×10135Pa).

2) β-type: Transformed into α-type at 982°C.

3) γ type: white orthorhombic crystal. The relative density is 4.28, and it transforms into β form when heated to 811°C. All three are toxic, slightly soluble in water, insoluble in ethanol, and soluble in acid and ammonium chloride solutions. It decomposes into barium oxide and carbon dioxide when heated to 1360°C under normal pressure.

Barium carbonate [Preparation]

At present, the industrial production of barium carbonate mainly uses the soda ash method and the carbonization method. In addition, there are also metathesis methods and toxobenite conversion methods.

1. Soda ash method

The main reaction formula of soda ash and barium sulfide (obtained by calcining barite) is;

This method has a short production process, high product purity, and easy-to-obtain raw materials. The disadvantage is that the barium carbonate produced contains alkaline components, and the sodium sulfide solution is relatively dilute, so it has little recycling value.

2. Carbonization method

Pour carbon dioxide gas into the barium sulfide solution for carbonization to obtain barium carbonate slurry. After desulfurization, washing, vacuum filtration, drying and pulverization at 300 C, the finished product of barium carbonate is obtained. The reaction is as follows

3. Metathesis method

The finished product of barium carbonate is obtained by carrying out a metathesis reaction between barium sulfide and ammonium carbonate, and then washing, filtering, drying, etc.

Barium carbonate can also be produced by metathesis reaction of cyanobenzeneboronic acid with barium chloride or barium nitrate instead of barium sulfide.

4. Toxic heavy stone transformation method

At present, there are two main industrial methods: one is to crush the poisonous heavy stone ore and leach it with inorganic acid to convert the barium into the barium salt of the corresponding acid that is soluble in water. After being separated from the impurities, it is then mixed with sodium carbonate or sodium carbonate. Ammonium carbonate reacts to precipitate barium carbonate; another method is to roast the poisonous barite ore powder at high temperature to remove carbon dioxide and become barium oxide. After water immersion, it becomes soluble barium hydroxide, which is separated from impurities and carbonized to precipitate barium carbonate. . The product contains less sulfur and other impurities, but the production cost is high and the operating conditions are difficult. The former often consumes a large amount of inorganic acids and carbonates, and at the same time brings problems of equipment corrosion. The latter consumes a lot of energy due to high roasting temperature, and the barium oxide produced is unstable and can easily absorb carbon dioxide to form insoluble barium carbonate, resulting in a very low yield.

Barium carbonate [Application]

1. Electronics industry

Because barium carbonate has strong X-ray shielding ability, adding barium to the glass shell of a color TV or computer picture tube can effectively absorb X-rays generated under high-voltage current. Barium carbonate can also be used to produce radiation filters to absorb high-intensity radiation. Barium carbonate used as a radiation shielding material generally does not have very high purity requirements, which is enough to be above 97. High-purity barium carbonate is mainly used in the field of capacitors with high quality requirements. The content of iron impurities is decisive for these products.Influence. The miniaturized, millimeter-level chip capacitors that have appeared in recent years must use four nines (99.99) high-purity barium carbonate. When barium carbonate is used as a raw material to produce barium ferrite for perpendicular magnetization, the impurity content of strontium and sodium is very small, and the particle diameter is within a certain range.

2. Glass and ceramics industry

In glass manufacturing, barium carbonate is used as a baking additive to increase pourability. Adding barium carbonate can improve the quality of glass, such as making the glass have a higher refractive index and greater hardness, and improving the performance and scratch resistance of the glass. In the production of optical special glasses, barium carbonate is an important source of barium oxide. Powdered barium carbonate is used in the production of structural ceramics. Improves the hardness, wear resistance and chemical corrosion resistance of ceramic tiles. Adding barium carbonate to ceramics can reduce pores and bubbles, improve translucency, expand the sintering range, and increase the thermal expansion coefficient. Barium is used as the glaze to improve the baking and scratch resistance of the glaze, making the color firm and bright.

3. Production of chemical raw materials

Barium carbonate can be used in the production of sodium tripolyphosphate and is used to remove sulfate radicals in wet phosphoric acid. When barium carbonate is used in the production of ferrite, it can improve its chemical properties. Barium carbonate is also used in the production of other barium chemicals (such as barium nitrate and barium oxide) and coatings and mica pigments.

4. Other industries

In water purification and waste treatment, barium carbonate is used as a precipitant to remove sulfate radicals. Barium carbonate can be used for steel carburizing and metal surface treatment. It is also an auxiliary raw material for the manufacture of enamel, rubber and polishing agents. Adding barium carbonate A to the flux can enhance its elasticity, improve its appearance, and increase its corrosion resistance.

Barium carbonate [Reference]

[1] Chen Yingjun; Wang Xu. Market status and development direction of barium carbonate in my country. Modern Chemicals, 2002, 22.5: 53-55.

[2] Li Jianzhong, Yuan Wei. Application and preparation of barium carbonate. Shaanxi Chemical Industry, 2000, 29(1), 6-9.

[3] Zhu Yingquan. “Comparison of physical and chemical properties of high-purity barium carbonate at home and abroad.” Electronic Components and Materials, 6 (2000): 37-39.

[4] Dictionary of Inorganic Compounds