As an important member of basic chemical raw materials and "three acids and two alkalis", Caustic Soda is closely related to national economic life. Its upstream mainly includes raw salt and power industry, and its downstream involves alumina, paper, textile printing and dyeing, Detergent, medicine, Water Treatment, oil, food processing and other industries. China's caustic soda industry has been developing for nearly a hundred years, with its output and consumption ranking first in the world, and its export volume also ranking first in the world. With the continuous introduction of national industrial policies to guide the healthy and stable development of the industry, caustic soda enterprises with scale and cost advantages will usher in new development opportunities.
[A] [Introduction to China's caustic soda industry]
Sodium hydroxide, namely sodium hydroxide, is an inorganic compound and a hazardous chemical. Its chemical formula is NaOH, also known as caustic soda and caustic soda. It has strong alkalinity, strong corrosivity and strong hygroscopicity.
According to different forms, caustic soda can be divided into liquid caustic soda and solid caustic soda. Liquid caustic soda is referred to as liquid caustic soda, which is usually colorless and transparent liquid. According to the mass fraction of sodium hydroxide, liquid caustic soda can be subdivided into 30% liquid caustic soda, 32% liquid caustic soda, 42% liquid caustic soda, 45% liquid caustic soda, 48% liquid caustic soda, 49% liquid caustic soda, 50% liquid caustic soda, etc. Among them, 32% liquid caustic soda and 50% liquid caustic soda are the mainstream models in the market, and are also the two delivery models of caustic soda futures listed in the later stage. Solid caustic soda is referred to as solid caustic soda for short, including flake caustic soda and granular caustic soda. In China, flake caustic soda is the main form. According to the mass fraction of sodium hydroxide, solid caustic soda can be subdivided into 73% solid caustic soda, 95% solid caustic soda, 96% solid caustic soda, 99% solid caustic soda, 99.5% solid caustic soda, etc. Among them, 99% flake caustic soda is the mainstream model in the market.
As a member of "three acids and two alkalis", caustic soda, like soda ash, is an important basic chemical raw material. The upstream of caustic soda mainly includes raw salt and power industries, and the downstream includes more than ten industries, such as alumina, paper making, textile printing and dyeing, detergent, medicine, water treatment, oil, food processing, etc. Specifically, caustic soda is mainly used to produce pulp, alumina, soap, dyes, rayon, smelting metal, petroleum refining, cotton fabric finishing, purification of coal tar products, water treatment, food processing, wood processing and machinery industry Chemical industry (preparation of borax, chromate, manganate, phosphate, production of polycarbonate, super absorbent polymer, Zeolite, epoxy Resin, sodium phosphate, sodium sulfite and a large number of sodium salts, chemicals and organic intermediates, regeneration of old rubber), etc. The upstream of caustic soda is relatively simple, and the consumer end is relatively complex. Its downstream is closely related to national life, covering various fields such as clothing, food, housing and transportation. Its demand has shown a steady growth trend in the past decade.
[B] [Main production process of caustic soda]
Caustic soda production process includes caustic process and electrolytic process. Among them, caustic process is soda caustic process, and electrolytic process can be divided into mercury process, membrane process and ion exchange membrane process. At present, ion-exchange membrane electrolysis is the mainstream production process in caustic soda industry.
The caustic soda industry in China originated from the establishment of Shanghai Tianyuan Electrochemical Plant in 1929. At first, the caustic process was widely used in China, but after 2000, the electrolytic process gradually replaced the caustic process as the main production method. At present, all domestic caustic soda enterprises in production use the ion-exchange membrane electrolysis method.
Caustic caustic soda is made from soda ash and mainly depends on natural soda resources, with low production cost and high economic benefits. However, due to the limited alkali ore resources and the small output of caustic process in China, the national policy restricts it. Around 2000, Chinese enterprises completely eliminated the production process. The production process of caustic process is not complicated, and its reaction formula is Na2CO3+Ca (OH) 2=2NaOH+CaCO3 ↓. The causticization method mainly includes three production steps: the first step is causticization, the second step is evaporation, and the third step is salting out. In the causticization stage, caustic soda solution shall be prepared in the causticization tank, quicklime shall be added, and the causticization reaction shall be continuously stirred, and then the brine cleaning solution shall be filtered. In the evaporation stage, the qualified brine cleaning solution is prepared by medium-concentration evaporation and high-concentration evaporation in order to remove the impurities of sodium sulfate, sodium carbonate and sodium chloride and obtain high-concentration sodium hydroxide. In the salting-out stage, the highly concentrated solution is further separated out of crystals, filtered, and sent to the cold-separation tank. The qualified products are precipitated in an intermittent sedimentation tank to obtain flake alkali.
According to the difference of electrolyzer structure, electrode material and diaphragm material, electrolytic method can be divided into mercury method, diaphragm method and ion exchange membrane method. At present, the ion-exchange membrane electrolysis method is the mainstream process of caustic soda production in China, and its chemical reaction formula is 2NaCl+2H2O=2NaOH+Cl2 ↑+H2 ↑.
Mercury electrolysis is a method to separate chlorine gas and obtain caustic soda by producing sodium and mercury. The electrolytic cell is composed of an electrolytic chamber and a mercury chamber. The advantage of this process is that the concentration of sodium hydroxide in the effluent solution of the electrolytic cell is high, and its mass fraction can reach 50%, without evaporation and concentration; The product quality is high and the salt content is low. However, due to the high energy consumption of the process and the mercury is a harmful substance, the process has been basically eliminated.
Diaphragm electrolysis method is a method to obtain caustic soda by separating chlorine gas generated by anode from sodium hydroxide and hydrogen generated by cathode, using porous and permeable asbestos diaphragm as interlayer, graphite as anode and iron as cathode. Its main processes include brine refining, brine electrolysis, electrolyte evaporation, chlorine treatment, hydrogen treatment and waste gas absorption. The diaphragm electrolysis method has low requirements on the quality of refined brine and only needs to be refined once. Add refined brine into the electrolytic tank, flow from the anode chamber to the cathode chamber, get chlorine in the anode chamber, and get electrolyte and hydrogen in the cathode chamber. In the diaphragm electrolyte, the content of sodium hydroxide is only 10.8%, and the content of sodium chloride is as high as 16.4%. Therefore, the diaphragm method uses the four-effect countercurrent evaporation technology with complex process when evaporating the electrolyte, which is high in energy consumption and difficult to operate. As about 10% of solid crystalline salt will be produced during evaporation, the heating chamber will be seriously worn and corroded, and the average life of the heating chamber is only 3 years, which greatly increases the cost of diaphragm caustic soda. When dealing with chlorine, it needs to go through four processes: chlorine washing, cooling and mist removal, drying and compression. When dealing with hydrogen, it needs to go through four processes: hydrogen washing, compression, deoxidation and drying. The diaphragm electrolysis method has the disadvantages of low production intensity, low product purity and large environmental pollution, and has been replaced at present.
The ion-exchange membrane electrolysis method is a method of separating the anode chamber and cathode chamber of the electrolytic cell by using the perfluorinated sulfonic ACID cation exchange membrane with stable chemical performance, so as to obtain caustic soda and chlorine gas. In this method, the concentration of sodium hydroxide in the electrolyte obtained after salt water electrolysis is high, which can be directly sold as liquid alkali. The process flow of ionic membrane method is similar to that of diaphragm method, which also includes brine refining, brine electrolysis, electrolyte evaporation, chlorine treatment, hydrogen treatment and waste gas absorption processes. Different from the diaphragm method, the ionic membrane electrolysis method has higher requirements for brine and requires secondary refining. During brine electrolysis, refined brine is added to the anode of the electrolytic cell, and high-purity water is added to the cathode. After electrolysis, dilute brine and chlorine are obtained in the anode chamber, and electrolyte and hydrogen are obtained in the cathode chamber. The concentration of sodium hydroxide obtained in this step is high, generally up to 32%, while the content of sodium chloride is only 0.004%. In the electrolyte evaporation process, the ionic membrane process is simpler, and only needs three-effect or two-effect evaporation. Compared with diaphragm caustic soda, ion-exchange membrane caustic soda has less total investment, less environmental pollution, and lower energy consumption and production costs.
[C] [Supply and demand pattern of caustic soda in China]
The output of caustic soda in China ranks the first in the world, the supply is relatively concentrated, and the overall trend is increasing year by year. According to the data released by the China Chlor-Alkali Industry Association, from 2007 to 2022, China's caustic soda production capacity increased from 21.81 million tons to 46.58 million tons, with a total increase of 24.77 million tons, an increase of 113.57%, and an annual growth rate of about 5.19%. During this period, the annual output of caustic soda in China increased by 21.32 million tons to 39.81 million tons, with an increase of 121.21% and an average annual growth rate of 5.84%. Except for the decline of caustic soda production in 2015 due to the impact of supply-side structural reform and environmental protection policies, the production of other years increased. In 2022, the output of caustic soda in China was 39.81 million tons, an increase of 2.30% over 2021. Among them, the output of liquid caustic soda accounts for about 83% and that of solid caustic soda accounts for about 17%. The output of 32% and 50% of liquid caustic soda accounted for 59% and 19% respectively; The output of 99% flake caustic soda in solid caustic soda accounts for 14%.
In terms of regions, China's caustic soda supply is mainly concentrated in East China, North China and Northwest China. Among them, East China is the region with the most concentrated distribution of caustic soda in China, and its production capacity accounts for about 22.09 million tons, accounting for 49.88% of the country's total production capacity. The production capacity of North China and Northwest China is 7.62 million tons and 6.23 million tons respectively, accounting for 17.21% and 14.07% respectively. The proportion of production capacity in Central China, Southwest China, Northeast China and South China was 8.47%, 4.95%, 2.78% and 2.64% respectively. Although caustic soda production is relatively concentrated geographically, the concentration of domestic caustic soda industry is not high. By 2022, there are 163 caustic soda enterprises in China, and only 4 enterprises with a capacity of more than 1 million tons/year, accounting for only 10.40% of the total capacity. There are 20 caustic soda production enterprises with a capacity of 500000 to 1 million tons/year, accounting for 27.91% of the total capacity.
From the demand side, domestic demand for caustic soda shows a rapid growth trend. According to the data released by the China Chlor-Alkali Industry Association, from 2007 to 2022, the apparent consumption of caustic soda in China increased from 16.15 million tons to 37.01 million tons, a total increase of 20.83 million tons, an increase of 129.16%, and an annual growth rate of about 5.69%. The demand decreased slightly in 2015. On the one hand, the demand for caustic soda decreased due to the optimization of the downstream alumina-electrolytic aluminum industrial chain structure of caustic soda; On the other hand, it is affected by the decline of caustic soda production. In 2022, China's apparent consumption of caustic soda will drop slightly to 37.01 million tons, a year-on-year decrease of 1.27%, mainly due to the significant increase in exports.
From the perspective of geographical distribution, the demand for caustic soda in China is widely distributed. Among them, the province with the largest demand is Shandong Province, whose demand will reach 8.07 million tons in 2022, accounting for 21.52% of the total national demand. In addition to Shandong, consumption in Shanxi, Guangxi, Jiangsu, Zhejiang, Jiangxi, Guangdong, Henan, Hebei and Sichuan ranks second to tenth in the national demand, accounting for 8.43%, 6.82%, 6.73%, 6.42%, 6.34%, 5.95%, 5.42%, 4.89% and 3.92% respectively. The demand of the top five provinces accounted for 49.92% of the national demand, and the top ten provinces accounted for 76.44%.
From the perspective of downstream consumption structure, China's caustic soda consumption is dominated by alumina industry, followed by chemical industry, water treatment and medicine, paper making, textile printing and dyeing, light industry and petroleum and military industry. The demand of alumina industry accounts for about 31% of downstream consumption, chemical industry accounts for about 17%, water treatment, medicine and other industries account for about 15%, paper industry accounts for about 12%, textile printing and dyeing accounts for about 10%, light industry accounts for about 8%, and petroleum and military industry accounts for about 7%. With the growth of the national economy, the downstream demand for caustic soda also continues to increase. In the downstream industries, alumina and chemical industry are the main sources of growth of caustic soda demand. According to Bayer process, theoretically, about 0.1 tons of caustic soda is required to produce 1 ton of alumina. In practice, considering the loss and other factors, it takes about 0.15 tons of caustic soda to produce 1 ton of alumina. Since 2007, China's alumina output has increased significantly, reaching the level of 81.86 million tons in 2022, with a year-on-year increase of 5.66%. In the chemical industry, caustic soda has a wide range of applications. The output of most chemical products shows an increasing trend, and the consumption of caustic soda has also increased.
[D] [Domestic caustic soda trade flow]
The flow of caustic soda trade in China is characterized by "from west to east and from north to south". The caustic soda production in North China and East China is mainly liquid caustic soda, and the transportation and storage of liquid caustic soda is more difficult. Therefore, after meeting the local demand, the above areas mainly flow to the surrounding areas by truck or to Fujian and Guangdong in South China by sea. The northwest region mainly produces solid caustic soda, and the long-distance transportation of solid caustic soda is more convenient. The caustic soda in the northwest region mainly flows to East China, South China, Southwest and Central China by railway.
The sales mode of caustic soda is mainly divided into direct sales and distribution. Direct sales is the main sales mode of domestic caustic soda enterprises. The modes of transportation include pipeline transportation, automobile transportation, rail transportation and water transportation. Generally speaking, pipeline transportation is used in the park, and truck transportation is mainly used within 300 kilometers, and ship or railway transportation is usually used for long-distance transportation. As caustic soda belongs to hazardous chemicals, tank cars shall be used for the transportation of liquid caustic soda, and the vehicles shall be equipped with dangerous goods identification and escort, and the carrier company shall hold the dangerous goods road transportation license.
In terms of storage, solid caustic soda storage is more convenient and safe. In the industry, solid caustic soda is mostly packaged in bags and stored in ventilated and dry warehouses. The general storage cost is 1.0-1.4 yuan/ton/day. Liquid caustic soda is highly corrosive and the storage cost is relatively high. Generally, storage tanks with a capacity of 4000-7000 cubic meters are used for storage, and the storage fee is usually 1.2-1.7 yuan/ton/day.
In terms of pricing right, the current domestic caustic soda quotation is mainly divided into market price and ex-factory price, and there are different market price and ex-factory price quotations according to different models. Generally speaking, the market price is higher than the factory price, and the higher the sodium hydroxide mass fraction is, the higher the price is. On the spot market, some enterprises will quote at a discount of 100% of sodium hydroxide. At present, domestic caustic soda is mainly priced on a monthly basis, which is fully negotiated between upstream producers and downstream consumers.
[E] [Import and export of caustic soda]
With the advantages of production capacity and price, China is a major exporter of caustic soda in the world, and its import volume has remained low for a long time. According to customs data, in 2022, China's import volume of caustic soda was 8900 tons and export volume was 3.2477 million tons, with an increase of 118.88% over 2021. China's caustic soda export has been dominated by liquid caustic soda for a long time. However, due to the convenience of solid caustic soda transportation and lower storage costs, the proportion of domestic solid caustic soda export has increased significantly in 2011-2020. In 2021 and 2022, the supply of overseas liquid caustic soda was relatively tight, the export volume of domestic liquid caustic soda increased significantly, and the export proportion of solid caustic soda decreased.
The export destinations of China's caustic soda mainly include Asia, Oceania and Africa. The export volume of the above regions accounts for 47%, 34% and 11% of the total domestic caustic soda export volume respectively. Specifically, Australia, Indonesia, Vietnam, the Philippines and Brazil are the major exporters of Chinese caustic soda. In 2021, China exported 448300 tons of caustic soda to Australia, 180900 tons to Indonesia, 97400 tons to Vietnam, 61800 tons to the Philippines and 50200 tons to Brazil. In 2021, the exports of the top five caustic soda exporting countries accounted for 56.66% of China's caustic soda exports, and the top ten caustic soda exporting countries accounted for 66.19%. The export destination of caustic soda will not change much in 2022. From January to December 2022, China exported 828600 tons of caustic soda to Australia, 588400 tons to Indonesia, 136700 tons to Vietnam and 122300 tons to Brazil.
The development of China's caustic soda industry has been greatly affected by national policies, and has successively experienced institutional reform, production technology innovation and industrial structure adjustment. The development stage can be divided into exploration stage, preliminary development stage, rapid development stage and stable development stage. With the continuous growth of downstream demand for caustic soda and the rapid development of chlor-alkali industry, China's caustic soda industry has also increased. In order to improve the overall competitiveness of the caustic soda industry, reduce the consumption of energy and raw materials, and achieve sustainable development, the state has continuously issued industrial policies to guide the healthy and stable development of the industry. In this context, inefficient small enterprises and backward production capacity will be forced out under pressure. Leading enterprises in the industry will rely on resource advantages, cost advantages, technology advantages, market advantages, scale advantages, etc. to enhance competitiveness, promote industry concentration, improve industry capacity structure, and usher in new development opportunities.
