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Introduction to Basic Knowledge of Caustic Soda

September 11, 2023

Caustic Soda 44


Physical and chemical properties of Caustic Soda: caustic soda can be divided into two types: solid and liquid. Solid caustic soda density 2.13g/cm ³, Melting point 318 ℃, boiling point 1388 ℃, saturated vapor pressure 0.13 kPa (739 ℃), appearance as a white crystalline powder, easily soluble in water, ethanol, glycerol, insoluble in acetone, ether.

The production of caustic soda mainly relies on liquid caustic soda, with 32% liquid caustic soda as the main model. Liquid caustic soda can be divided into 32% liquid caustic soda, 50% liquid caustic soda, etc. based on the mass fraction of sodium hydroxide. 32% liquid alkali is the main model in caustic soda products, accounting for about 60% of the production, followed by 50% liquid alkali, which accounts for about 20% of the production.

Ion exchange membrane method is the mainstream process, with electricity accounting for the largest proportion of production costs. Ion exchange membrane technology is the mainstream production method in the world today, with ion exchange membrane method being the main method in the Chinese market, accounting for 99.65% of the total production capacity of caustic soda in China. On the raw material side, the unit consumption for producing one ton of caustic soda raw salt is 1.51 tons, and the cost of raw salt accounts for 12% -18%. Each ton of caustic soda production consumes approximately 2300-2400 kilowatt hours of electricity, accounting for about 60% of the total cost of caustic soda production.

The main producing areas of caustic soda in China are Shandong, Inner Mongolia, and Xinjiang: in 2022, China's caustic soda production will reach 39.805 million tons. The average annual growth rate from 2013 to 2022 is 4.0%. Before 2014, the entry threshold for the caustic soda industry was relatively low, and the growth rate of production was relatively fast. After 2014, due to factors such as the promotion of supply side reform and stricter environmental inspections, the growth rate of caustic soda production slowed down. In recent years, with the continuous expansion of downstream alumina production capacity, the production capacity of caustic soda has also increased. The top 5 provinces/autonomous regions in China's caustic soda production in 2021 were Shandong, Inner Mongolia, Xinjiang, Jiangsu, and Zhejiang, with a total production of 22.082 million tons of caustic soda, accounting for nearly 60% of the national production.

China's caustic soda is widely used downstream, with alumina being the largest downstream. China's caustic soda is widely used downstream, with alumina accounting for the largest proportion of downstream consumption, followed by printing and dyeing, chemical fiber, and other fields such as papermaking, Water Treatment, lithium battery, and medicine. From the perspective of brand classification, 50% concentration caustic soda is mainly used in fields such as alumina, papermaking, soap making, textiles, printing and dyeing, and chemical fibers, while 32% concentration caustic soda is mainly used in water treatment, light industry and chemical industry, and other fields. In the past year, the average monthly consumption of caustic soda in China is about 3.3 million tons, slightly lower than the average monthly production of caustic soda. In 2022, domestic demand has declined due to the impact of the epidemic, and downstream demand in the printing, dyeing, and adhesive industries is weak.

Domestic caustic soda trade flows from west to east and from north to south: According to public information, Inner Mongolia, Shandong, and Xinjiang were the top three net outflow regions of caustic soda in China in 2021, with net outflow accounting for over 60% of the total outflow. Shanxi, Guangdong, and Guangxi are the top three net inflow regions of caustic soda in China, with the net inflow accounting for nearly 60% of the total inflow.

China is a net exporter of caustic soda, with strong exports in recent years: between 2018 and 2022, the total annual import volume of caustic soda was about 44000 tons, and the total annual export volume of caustic soda was about 1.7 million tons. According to Baichuan Yingfu, currently China's liquid alkali mainly imports from countries such as Sweden, Japan, Norway, and the United States, and exports mainly to countries such as Australia and Indonesia.

Physical and chemical properties of caustic soda

Caustic soda, scientific name sodium hydroxide, chemical formula NaOH, also known as caustic soda or caustic soda, is an inorganic compound. Caustic soda is a fundamental chemical raw material for the national economy, and is one of the two alkalis in the "three acids and two alkalis" category, along with soda ash. Caustic soda can be divided into two types: solid and liquid. Solid caustic soda density 2.13g/cm ³, Melting point 318 ℃, boiling point 1388 ℃, saturated vapor pressure 0.13 kPa (739 ℃), appearance as a white crystalline powder, easily soluble in water, ethanol, glycerol, insoluble in acetone, ether. Caustic soda has a corrosive effect on fibers, skin, glass, ceramics, etc. When dissolved or diluted with a concentrated solution, it will release heat; Neutralization reaction with inorganic acids can also generate a large amount of heat, generating corresponding salts; React with metal aluminum and zinc, non-metallic boron and silicon to release hydrogen; Disproportionation reaction occurs with halogens such as chlorine, bromine, and iodine. Able to precipitate metal ions from aqueous solutions into hydroxides; Sodium salts and alcohols that can cause saponification reactions in fats and oils, generating corresponding organic acids. When storing caustic soda, it should be stored in a cool, dry, and well ventilated warehouse. Keep away from sparks and heat sources. The temperature of the warehouse shall not exceed 35 ℃, and the relative humidity shall not exceed 80%. The packaging must be sealed and protected from moisture. It should be stored separately from combustible materials and should not be mixed for storage. The storage area should be equipped with suitable materials to contain leaks.

Caustic soda production is mainly based on liquid alkali, with 32% liquid alkali as the main model

Caustic soda can be classified into liquid and solid based on its morphology, with liquid caustic soda accounting for about 80% of the production and solid caustic soda accounting for about 20%. Liquid caustic soda can be directly sold as a product, and solid caustic soda is obtained by further concentration. Liquid caustic soda can be divided into 32% liquid caustic soda, 50% liquid caustic soda, etc. based on the mass fraction of sodium hydroxide. 32% liquid alkali is the main model in caustic soda products, accounting for about 60% of the production, followed by 50% liquid alkali, which accounts for about 20% of the production. Solid caustic soda can be divided into flake caustic soda, granular caustic soda, etc. according to its form, and flake caustic soda accounts for approximately 14% of the caustic soda production. According to the mass fraction of sodium hydroxide, solid caustic soda can be divided into 96% solid caustic soda, 99% solid caustic soda, etc. Among them, the mainstream model of solid caustic soda is 99% flake caustic soda.

Ionic membrane method is the mainstream process, with the largest proportion of electricity in production costs

The production process of caustic soda includes chemical method (causticization method) and electrolysis method. Causticization method is the reaction of lime milk and pure alkali aqueous solution to produce caustic soda. Due to the low purity and poor economic benefits of the caustic soda produced by this method, it is currently only produced on a small scale in a few countries. The main raw material for the electrolysis method is raw salt. The electrolysis method is also known as the separation membrane method, mercury method, and ion exchange membrane method. Ion exchange membrane technology is the mainstream production method in the world today, with ion exchange membrane technology being the main method in the Chinese market, accounting for 99.65% of the total production capacity of caustic soda in China. Due to its high energy consumption and lower product quality than ionic membrane alkali, diaphragm alkali will gradually withdraw from the caustic soda industry according to market patterns.

On the raw material side, the unit consumption for producing one ton of caustic soda raw salt is 1.51 tons, and the cost of raw salt accounts for 12% -18%. Each ton of caustic soda production consumes approximately 2300-2400 kilowatt hours of electricity, accounting for about 60% of the total cost of caustic soda production. Relatively speaking, due to the abundant resources in regions such as Northwest and North China, the production cost of caustic soda is relatively low. According to the prospectus of Beiyuan Group, in 2019, the unit consumption of raw salt in caustic soda manufacturing was 0.78 tons, the unit consumption of electricity was 1365.74 degrees Celsius, and the unit consumption of steam was 0.55 tons. In the total production cost, electricity accounted for about 55%, and the cost of raw salt accounted for about 9%. Overall, electricity is the most important component of the production cost of caustic soda. In addition, due to the production process of caustic soda also producing chlorine gas, usually producing 1 ton of ion exchange membrane converted into 100% caustic soda can produce 0.886 tons of chlorine gas. In the chlor alkali industry, metric electrochemical unit cost is usually used as the cost unit for accounting, abbreviated as ECU, which is the cost of producing 1 unit of chlorine gas and 1.13 units of caustic soda (converted into 100%).

Caustic soda and PVC are core products in the chlor alkali industry chain

Caustic soda and PVC are core products in the chlor alkali industry chain. The downstream application industries of the chlor alkali industry are extensive, mainly including alumina, light industry, printing and dyeing, chemical industry, viscose staple fiber, papermaking, petroleum, etc. Among them, alumina accounts for the largest proportion of consumption, followed by the chemical and light industry industries. In the chemical and light industry, the application of chlor alkali products is not limited to specific products, but has a wide range of applications throughout the industry, including detergents, soap, glass, organic chemicals, inorganic chemicals, chemical drugs, and other products.

China is the world's largest producer and consumer of caustic soda

Before 2015, the growth rate of global caustic soda production capacity was relatively fast, and since 2015, the growth rate of global caustic soda production capacity has been relatively stable. As of 2021, the global caustic soda production capacity is approximately 86.446 million tons, with China being the largest country in the world. In the distribution of global caustic soda production capacity in 2021, China accounted for 27.675 million tons, accounting for 32%; 17.641 million tons in the United States, accounting for 21%; Japan has 5.149 million tons, accounting for 6%; Germany has 4.608 million tons, accounting for 5%, while India has 3.752 million tons, accounting for 4%; Other countries account for 32%.

On the demand side, the global demand for caustic soda is showing a fluctuating and increasing trend. From 2010 to 2022, global demand for caustic soda increased from 60.9 million tons to 84.52 million tons. In terms of demand distribution pattern: China is also the world's largest consumer of caustic soda. In 2022, China's demand for caustic soda accounted for 44.8% of the world, followed by North America accounting for 14.2% and Western Europe accounting for 12.3%.

According to the chlor alkali chemical information network, in 2022, the global trade volume of caustic soda accounted for over 15% of the production, mainly liquid caustic soda products, while solid caustic soda products had relatively low production and low circulation. The United States is the country with the largest global export volume of liquid alkali, and has a cost advantage. The annual export volume of liquid alkali accounts for 35% of the global trade volume of liquid alkali. As the world's largest producer of caustic soda, China ranks second in terms of export volume. The main import regions of global liquid alkali are Australia, Brazil, Finland, Canada, the United States, Sweden, France, the Netherlands, and Spain. Among them, Australian liquid alkali imports account for over 1/5 of global liquid alkali trade, mainly from China and the United States. The export volume of caustic soda products in the Indian region exceeded the import volume for the first time in 2021, and the trade direction has changed. The local caustic soda export volume will continue to increase in 2022. In addition to China's exports, India, Russia, Poland, Thailand, Belgium, and Saudi Arabia also export a small amount of global solid alkali. Among them, China has the largest export volume of solid alkali, accounting for over 40% of global solid alkali trade volume. The export volume of solid alkali from India, Thailand, and Saudi Arabia has also increased. The main import regions of solid alkali in the world are Vietnam, Nigeria, Indonesia, Uzbekistan, Tanzania, Kazakhstan, etc.

The main producing areas of caustic soda in China are Shandong, Inner Mongolia, and Xinjiang

In 2022, China's caustic soda production reached 39.805 million tons. The average annual growth rate from 2013 to 2022 is 4.0%. Before 2014, the entry threshold for the caustic soda industry was relatively low, and the growth rate of production was relatively fast. After 2014, due to factors such as the promotion of supply side reform and stricter environmental inspections, the growth rate of caustic soda production slowed down. In recent years, with the continuous expansion of downstream alumina production capacity, the production capacity of caustic soda has also increased. The top 5 provinces/autonomous regions in China's caustic soda production in 2021 were Shandong, Inner Mongolia, Xinjiang, Jiangsu, and Zhejiang, with a total production of 22.082 million tons of caustic soda, accounting for nearly 60% of the national production.

The regional distribution of caustic soda production capacity in China is mainly close to the origin or consumption of raw materials. The northwest region has abundant resources such as raw salt and coal, while the alumina, textile printing and dyeing, and papermaking industries are relatively concentrated in the eastern and northern regions of China. The concentration of the caustic soda industry is relatively low. According to data from Baichuan Yingfu, only 3 out of 182 caustic soda enterprises have an effective production capacity exceeding 1 million tons, with CR5 being 12%, CR10 being 19%, and CR20 being 33%. Among the main production enterprises of caustic soda, two enterprises in Xinjiang have an effective production capacity of over one million tons, five enterprises in Shandong Province have an effective production capacity of 800000 tons in Shaanxi Beiyuan, 750000 tons in Jiangsu Taixing Xinpu, and 720000 tons in Shanghai chlor alkali.

China's caustic soda is widely used downstream, with alumina being the largest downstream

China's caustic soda is widely used downstream, with alumina accounting for the largest proportion of downstream consumption, followed by printing and dyeing, chemical fiber, and other fields such as papermaking, water treatment, lithium battery, and medicine. From the perspective of brand classification, 50% concentration caustic soda is mainly used in fields such as alumina, papermaking, soap making, textiles, printing and dyeing, and chemical fibers, while 32% concentration caustic soda is mainly used in water treatment, light industry and chemical industry, and other fields. In the past year, the average monthly consumption of caustic soda in China is about 3.3 million tons, slightly lower than the average monthly production of caustic soda. In 2022, domestic demand has declined due to the impact of the epidemic, and downstream demand in the printing, dyeing, and adhesive industries is weak.

China's alumina production capacity is mainly distributed in Shandong, Shanxi, and Guangxi

In the production of aluminum oxide, caustic soda is mainly used to adjust the acidity and alkalinity of aluminum liquid, increase grain size, and improve production efficiency and product quality. In the process of aluminum smelting, the preparation of cryolite and the treatment of bauxite used in alumina require the use of soda ash and caustic soda. In theory, producing 1 ton of alumina consumes 0.14-0.16 tons of caustic soda, which accounts for approximately 16% of the production cost of alumina.

The production capacity of alumina is mainly distributed in provinces such as Shandong, Shanxi, Guangxi, and Henan. The total production capacity of Shandong is about 30 million tons, the total production capacity of Shanxi is about 26.55 million tons, the total production capacity of Guangxi is about 15.1 million tons, and the total production capacity of Henan is about 10 million tons. Among the main alumina production enterprises, there are 4 in Shandong, 3 in Shanxi, and 1 each in Hebei, Chongqing, and Guangxi. The main groups include China Aluminum Corporation, Weiqiao Group, Xinfa Group, Jinjiang Group, and Oriental Hope Group.

The production capacity of viscose staple fibers in China is mainly distributed in Xinjiang, Jiangxi, and Hebei

In the printing and dyeing industry, caustic soda is mainly used to remove impurities from the surface of cotton fibers, allowing dyes to penetrate into the inner layer of the fibers during dyeing, making the dyeing more uniform. In the chemical fiber industry, alkali cellulose can be obtained by treating cellulose with caustic soda, and ultimately viscose fibers (rayon) can be produced. Usually, producing 1 ton of rayon requires 1 ton of caustic soda. The demand for caustic soda in the printing and dyeing and chemical fiber industries is mainly influenced by the market situation in the textile industry.

The production capacity of viscose staple fibers in China is mainly distributed in provinces such as Xinjiang, Jiangxi, Hebei, and Jiangsu. The total production capacity of Xinjiang is about 970000 tons, that of Jiangxi is about 920000 tons, that of Hebei is about 865000 tons, and that of Jiangsu is about 860000 tons. Among the main production enterprises, Hebei Sanyou Group has a production capacity of 830000 tons, Xinjiang Zhongtai Textile has a production capacity of 400000 tons, and Saideli Group (foreign-funded) is one of the world's largest cellulose fiber manufacturers.

China's wood pulp production capacity is mainly distributed in Shandong, Guangxi, and Guangdong

In the papermaking industry, caustic soda is used to remove lignin, carbohydrates, and resins, producing pulp mainly composed of cellulose and improving paper quality; In addition, caustic soda can also play a bleaching role as an auxiliary agent. The proportion of caustic soda used in the pulp production process is relatively fixed, and 1 ton of pulp usually requires 0.08 tons of caustic soda to be consumed. During the papermaking process, there are significant differences in the consumption of caustic soda due to different types of finished paper. The proportion of raw material caustic soda in the production cost of wood pulp is about 5%.

The production capacity of wood pulp in China is mainly distributed in provinces such as Shandong, Guangxi, Guangdong, and Hainan. The total production capacity of Shandong is about 729000 tons, that of Guangxi is about 340000 tons, that of Guangdong is about 257000 tons, and that of Hainan is about 190000 tons. Among the main production enterprises of wood pulp, Asia Pacific Senbo has a production capacity of 2.1 million tons, Hainan Jinhai has a production capacity of 190000 tons, and Sun Paper and Chenming Paper are key enterprises in the paper industry.

Domestic caustic soda trade flows from west to east and from north to south

China's caustic soda trade flows from west to east and from north to south. Due to its characteristics, liquid alkali is generally sold mainly through transportation within a radius of 300km in and around provinces; Sales of water transportation exceeding 300km are relatively rare and generally occur in port area trade. The inland transportation radius of solid alkali by truck is 300-500km, and the transportation radius from the northwest region to the inland railway transfer line can reach 2000km. According to public information, Inner Mongolia, Shandong, and Xinjiang were the top three net outflow regions of caustic soda in China in 2021, with net outflow accounting for over 60% of the total outflow. Among them, Shandong caustic soda sales flow to surrounding areas through truck transportation, and to Fujian and Guangdong through sea transportation. Xinjiang and Inner Mongolia mainly sell solid alkali, mainly flowing to East China, South China, and Central China. Shanxi, Guangdong, and Guangxi are the top three net inflow regions of caustic soda in China, with the net inflow accounting for nearly 60% of the total inflow.

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