Barium Metal (1)

1、 Basic Introduction

Chinese name: Barium, English name: Barium, element symbol Ba, atomic number 56 in the periodic table, is an IIA group alkaline earth metal element with a density of 3.51 g/cubic centimeter, a melting point of 727 ° C (1000 K, 1341 ° F), and a boiling point of 1870 ° C (2143 K, 3398 ° F). Barium is an alkaline earth metal with a silver white luster, with a flame color of yellow green, soft, and ductile. Barium has very active chemical properties and can react with most non-metals. Barium has never been found as a single substance in nature. Barium salts are toxic except for barium sulfate. In addition, metallic barium has a strong reducibility and can reduce most metal oxides, halides, and sulfides to obtain corresponding metals. The content of barium in the crust is 0.05%, and the most common minerals in nature are barite (barium sulfate) and witherite (barium carbonate). Barium is widely used in fields such as electronics, ceramics, medicine, and petroleum.

2、 The Discovery of Barium and the Development Status of China’s Barium Industry

1. A brief history of the discovery of barium

Alkaline earth metal sulfides exhibit phosphorescence, meaning that they continue to emit light in the dark for a period of time after being exposed to light. It is precisely because of this characteristic that barium compounds have begun to receive attention.

In 1602, V. Casiorolus, a shoemaker in Bologna, Italy, discovered that a barite containing barium sulfate emitted light in the dark after roasting it with combustible substances. This phenomenon aroused the interest of European chemists. In 1774, Swedish chemist C.W. Scheele discovered a new element in barite, but he was unable to separate it, only the oxide of that element. In 1776, Johan Gottlieb Gahn isolated this oxide in a similar study. Baryta was initially referred to as barote by Guyton de Morveau, and later renamed baryta (heavy earth) by Antoine Lavoisier. In 1808, British chemist Humphry Davy used mercury as the cathode, platinum as the anode, and electrolyzed barite (BaSO4) to produce barium amalgam. After distillation to remove mercury, a metal with low purity was obtained and named barium.

Industrial applications also have a history of over a hundred years

As early as the mid-19th century, people began to use barite (an important mineral for producing barium and barium compounds) as a filler for paints. Since this century, barite has become the main raw material for manufacturing various barium containing chemical products. Due to its significant proportion, stable chemical properties, and insoluble in water and acids, barite has been used as a weighting agent for oil and gas drilling mud as early as the 1920s. Barium sulfate is used in the production of white pigments and can be used as a filler and colorant for rubber.

2. Situation of China’s barium industry

Common barium salts include barium sulfate, barium nitrate, barium chloride, barium carbonate, barium cyanide, etc. Barium salt products are mainly used in the electronic industry as additives for color picture tubes and magnetic materials.

At present, China has become the world’s largest producer of barium salts. The global annual production capacity of barium carbonate is about 900000 tons, with an output of about 700000 tons, while China’s annual production capacity is about 700000 tons, with an annual output of about 500000 tons, accounting for over 70% of the global barium carbonate production capacity and output. China’s barium carbonate products have been exported in large quantities for a long time, and China has become the world’s largest exporter of barium carbonate.

The Problems Faced by the Development of Barium Salt Industry in China

Although China is the world’s largest producer and exporter of barium carbonate, it is not a strong producer of barium carbonate. Firstly, there are few large-scale barium carbonate production enterprises in China, and there are very few enterprises that have achieved large-scale production; Secondly, China’s barium carbonate products have a single structure and lack high-tech products. Although some factories are currently researching and producing high-purity barium carbonate, its stability is poor. For high-purity products, China also needs to import from companies such as Germany, Italy, and Japan. In addition, in recent years, some countries have become new exporters of barium carbonate, such as Russia, Brazil, South Korea, and Mexico, leading to oversupply in the international barium carbonate market, which has had a huge impact on China’s barium carbonate industry. Manufacturers are willing to reduce prices in order to survive. At the same time, Chinese export enterprises are also facing anti-dumping investigations from abroad. With the continuous improvement of environmental protection requirements, some barium salt production enterprises in China are also facing environmental protection issues. In order to promote the development of China’s barium salt industry, barium salt production enterprises in China should take environmental protection and safety as the foundation, continuously research and introduce advanced technologies, and develop new products that meet the requirements of the times and have high technological content.

Production and Export Data of Barite in China

According to data from the United States Geological Survey, the production of barite in China was approximately 41 million tons in 2014. According to Chinese customs statistics, from January to December 2014, China exported 92588597 kilograms of barium sulfate, an increase of 0.18% compared to the same period last year. The cumulative export value was 65496598 US dollars, an increase of 20.99% compared to the same period last year. The export unit price was 0.71 US dollars per kilogram, an increase of 0.12 US dollars per kilogram compared to the same period last year. Among them, in December 2014, China exported 8768648 kilograms of barium sulfate, an increase of 8.19% compared to the same period last year. The export amount was 8385141 US dollars, an increase of 5.1% compared to the same period last year.

According to Chinese customs data, in June 2015, China exported 170000 tons of barium sulfate, a decrease of 1.7% compared to the same period last year; In the first half of the year, the cumulative export volume was 1.12 million tons, a decrease of 6.8% compared to the same period last year; The same export amount decreased by 5.4% and 9% respectively compared to the same period last year.

3、 Distribution and Production of Barium (Barite) Resources

1. Distribution of barium resources

The content of barium in the crust is 0.05%, ranking 14th. The main minerals in nature are barite (barium sulfate BaSO4) and witherite (barium carbonate BaCO3). Among them, barite is the most common mineral of barium, which is composed of barium sulfate and occurs in low-temperature hydrothermal veins, such as quartz barite veins, fluorite barite veins, etc. Toxicite is another major barium containing mineral in nature, in addition to barite, and its main component is barium carbonate.

According to data from the United States Geological Survey in 2015, the global barite resource is approximately 2 billion tons, of which 740 million tons are proved. The global barite reserves are 350 million tons. China is the country with the most abundant barite resources. Other countries with rich barite resources include Kazakhstan, Türkiye, India, Thailand, the United States and Mexico. Famous sources of barite in the world include Westman Land in the UK, Felsbonne in Romania, Saxony in Germany, Tianzhu in Guizhou, Heifenggou in Gansu, Gongxi in Hunan, Liulin in Hubei, Xiangzhou in Guangxi, and Shuiping in Shaanxi.

According to data from the United States Geological Survey in 2015, the global production of barite was 9.23 million tons in 2013 and increased to 9.26 million tons in 2014. In 2014, China was the largest producer of barite, with a production of 4.1 million tons, accounting for approximately 44.3% of the global total production. India, Morocco, and the United States rank second, third, and fourth respectively, with production of 1.6 million tons, 1 million tons, and 720000 tons.

2. Distribution of Barium Resources in China

China is rich in barium ore resources, with a predicted total reserve of over 1 billion tons. Moreover, the grade of barium ore is relatively high, and its reserves and production are currently ranked first in the world. The most common barium containing mineral in nature is barite. The global reserve of barite is 350 million tons, while the reserve of barite in China is 100 million tons, accounting for approximately 29% of the total global reserve and ranking first in the world.

According to the data in “Exploration of the Main Mineral Concentration Areas and Resource Potential of China’s Barite Mines” (Chemical Mineral Geology, 2010), China is rich in barite resources, distributed in 24 provinces (regions) nationwide, with reserves and production ranking first in the world. There are 195 mining areas with proven reserves in China, with a total confirmed resource reserve of 390 million tons of ore. From the provincial (regional) distribution of barite, Guizhou Province has the most barite mines, accounting for 34% of the country’s total reserves; Hunan, Guangxi, Gansu, Shaanxi and other provinces (regions) take second place. The above five provinces account for 80% of the national reserves. The deposit type is mainly sedimentary, accounting for 60% of the total reserves. In addition, there are also layer controlled (endogenetic), volcanic sedimentary, hydrothermal, and weathered (residual slope) types. The mineralization period was mainly in the Paleozoic era, and barite deposits were also formed during the Sinian and Mesozoic Cenozoic periods.

Characteristics of Barite Mineral Resources in China

From a quantitative perspective, barite minerals in China are mainly distributed in the central region; In terms of grade, almost all rich minerals are mainly concentrated in Guizhou and Guangxi; From the perspective of ore deposit scale, China’s barite deposits are mainly large and medium-sized. Only the two mining areas of Guizhou Tianzhu Dahe Bian and Hunan Xinhuang Gongxi account for more than half of the reserves in these areas. Often, a single barite type is the main ore type, and the mineral composition and chemical composition ratio are relatively simple and pure, such as the Hunan Xinhuang Gongxi barite mine. In addition, there are also large reserves of co and associated minerals that can be comprehensively utilized.

4、 Production process of barium

1. Preparation of barium

The production of metallic barium in industry includes two steps: the production of barium oxide and the production of metallic barium through metal thermal reduction (aluminothermic reduction).

(1) Preparation of barium oxide

High quality barite ore first requires manual selection and flotation, followed by iron and silicon removal to obtain a concentrate containing more than 96% barium sulfate. Mix mineral powder with a particle size less than 20 mesh and coal or petroleum coke powder in a weight ratio of 4:1, and calcine at 1100 ℃ in a reverberatory furnace. Barium sulfate is reduced to barium sulfide (commonly known as “black ash”), which is leached with hot water to obtain a solution of barium sulfide. In order to convert barium sulfide into barium carbonate precipitation, it is necessary to add sodium carbonate or introduce carbon dioxide into the barium sulfide aqueous solution. Mix barium carbonate with carbon powder and calcine at above 800 ℃ to obtain barium oxide. It should be noted that barium oxide oxidizes to form barium peroxide at 500-700 ℃, and barium peroxide can decompose to form barium oxide at 700-800 ℃. Therefore, to avoid producing barium peroxide, the calcined products need to be cooled or quenched under inert gas protection.

(2) Production of barium metal by aluminothermic reduction method

There are two reactions for aluminum reduction of barium oxide due to different ingredients:

6BaO+2Al → 3BaO • Al2O3+3Ba ↑

Or: 4BaO+2Al → BaO • Al2O3+3Ba ↑

At temperatures ranging from 1000 to 1200 ℃, these two reactions produce very little barium, so it is necessary to use a vacuum pump to continuously transfer barium vapor from the reaction zone to the condensation zone in order for the reaction to proceed continuously to the right. The residue after the reaction is toxic and can only be discarded after treatment.

2. Preparation of common barium compounds

(1) Preparation method of barium carbonate

① Carbonization method

The carbonization method mainly involves mixing barite and coal in a certain proportion, crushing them into a rotary furnace, and roasting and reducing them at 1100-1200 ℃ to obtain barium sulfide melt. Carbon dioxide is introduced into the barium sulfide solution for carbonization, and the obtained barium carbonate slurry is subjected to desulfurization washing and vacuum filtration. Then, it is dried and crushed at 300 ℃ to obtain the finished barium carbonate product. This method is adopted by most manufacturers due to its simple process and low cost.

② Complex decomposition method

The final product of barium carbonate can be obtained by the double decomposition reaction between barium sulfide and ammonium carbonate, or by the reaction between barium chloride and potassium carbonate. The resulting product is then washed, filtered, dried, etc.

③ Toxic Heavy Petrochemical Law

The toxic heavy ore powder is reacted with ammonium salt to generate soluble barium salt, and ammonium carbonate is recycled for use. The soluble barium salt is added to ammonium carbonate to precipitate refined barium carbonate, which is filtered and dried to produce a finished product. In addition, the obtained mother liquor can be recycled and reused.

(2) Preparation method of barium titanate

① Solid-phase method

Barium titanate can be prepared by calcining barium carbonate and titanium dioxide, which can be doped with any other material.

② Coprecipitation method

Dissolve barium chloride and titanium tetrachloride in a mixture of equal substances, heat to 70 ° C, and then drop oxalic acid to obtain a precipitate of hydrated barium titanate [BaTiO (C2O4) 2-4H2O]. Wash, dry, and then pyrolysis to obtain barium titanate.

(3) Preparation method of barium chloride

The production process of barium chloride mainly includes hydrochloric acid method, barium carbonate method, calcium chloride method, and magnesium chloride method according to different methods or raw materials.

① Hydrochloric acid method.

② Barium carbonate method. Made from withered stone (barium carbonate) as raw material.

③ Calcium chloride method. Reducing a mixture of barite and calcium chloride with carbon.

In addition, there is the magnesium chloride method. Prepared by treating barium sulfide with magnesium chloride.