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From April 25th to 26th, the 2025 Titanium Dioxide Production Technology Innovation Achievements Exchange and Exhibition Conference was held in Xiangtan, Hunan Province. Nearly 200 representatives from over 100 titanium dioxide and upstream and downstream enterprises across the country gathered together to showcase and exchange the latest scientific and technological achievements and discuss the technological innovation and development of the titanium dioxide industry.

Bi Sheng, the secretary-general of the Titanium Dioxide Industry Technology Innovation Strategic Alliance, introduced. China's titanium dioxide industry was born in the mid-1950s and has a history of nearly 70 years up to now. However, the real development began after 1998. With the rapid growth of the national economy, the titanium dioxide industry also developed in tandem. In 2002, its overall scale surpassed that of Japan, ranking second in the world. It surpassed the United States in 2009 and has remained the world's number one ever since. In 2024, the total annual production capacity of titanium dioxide in China will reach 5.9 million tons, exceeding two-thirds of the global total. The output for that year will be 4.766 million tons, with an average capacity utilization rate of 80.8%.

However, when we look at the development achievements, we should also recognize and analyze the deficiencies on the development path. Bi Sheng pointed out that, to be realistic, although China is a major producer of titanium dioxide, it cannot yet be regarded as a production power. The quality of its products still lags behind the world's advanced level, and factors such as production processes and equipment technology are important. In addition, the environmental protection during the production process and the level of the circular economy industrial chain also need to be further improved and perfected.

Bi Sheng emphasized that reducing titanium dioxide waste residue will be the top priority for the industry's innovative development in the future. The industry and supporting enterprises have also been striving for it all along, developing many new technologies, new products, equipment manufacturing and supporting services for reducing wastewater, waste acid and waste residue, making significant contributions to the green and sustainable development of the titanium dioxide industry.

According to statistics, the output of titanium dioxide produced by the sulfuric acid process in 2024 is 4.103 million tons. On average, about 6 to 7 tons of waste acid are generated for every ton of titanium dioxide produced. When these waste acids are mixed with lime, approximately 7.5 tons of red gypsum residue will be produced. Therefore, the annual output of red gypsum residue will reach 30.77 million tons. If these titanium gypsum slags are directly piled up and disposed of, they will not only occupy a large amount of land, but also bring high disposal fees to the enterprises. If both acid and ferrous sulfate can be recovered from waste acid, it will not only generate obvious economic benefits but also help enterprises solve environmental protection problems.

Regarding the resource utilization of waste acid from the sulfuric acid process for titanium dioxide production, Feng Shengjun, the chairman of Nantong Sansheng Graphite Equipment Technology Co., LTD., stated that the company has successively developed three proprietary technologies and devices that are suitable for domestic working conditions, namely the fourth-generation mature waste acid evaporation and concentration, Venturta thin-film evaporation, and freezing crystallization, which can provide the recovery of ferrous sulfate heptahydrate. It can also provide a full-process technical solution for acid recovery, helping enterprises not only achieve significant environmental benefits such as substantial residue reduction but also generate considerable economic benefits. Among them, the multi-stage evaporation technology for waste acid has completely solved the two major technical problems of fouling and clogging of heat exchangers and the easy wear and short replacement cycle of the impeller of the two-stage circulation pump during its development process. In collaboration with Panzhihua Haifengxin, the first industrial device for titanium dioxide waste acid freezing crystallization technology was jointly developed. It has been operating stably for nearly one and a half years and has achieved online recovery and cleaning.

Feng Shengjun analyzed and pointed out that the disposal fee for each ton of gypsum slag ranges from 70 to 120 yuan depending on regional differences. If one ton of zebic acid is recycled, the production of titanium gypsum residue can be reduced by 3.5 tons accordingly, thus saving 245 to 420 yuan. If one ton of ferrous sulfate heptahydrate is recovered, two tons of titanium gypsum residue can be reduced, which can save 140 to 240 yuan. In addition, considering the intrinsic value of sulfuric acid and ferrous sulfate heptahydrate, due to price fluctuations, the gross profit brought by the recovery of one ton of sulfuric acid is 551 to 1,236 yuan, and the gross profit brought by the recovery of one ton of ferrous sulfate heptahydrate is also 140 to 820 yuan.

Based on the waste acid produced by a 100,000-ton titanium dioxide production capacity, compared with the technical process of only using multi-stage evaporation and concentration of waste acid to recover the finished acid, if the full-process technical process of extracting ferrous sulfate heptahydrate first through freezing crystallization and then evaporating and concentrating the waste acid to recover the finished acid is adopted, more acid can be recovered, more ferrous sulfate heptahydrate can be produced, and the amount of titanium gypsum residue can be reduced. Comprehensive calculation It can generate an additional economic benefit of over 50 million yuan each year, and at the same time, it can save 320,000 tons of land for the storage of titanium gypsum slag.

According to Wu Zhengming, the general manager of Nanjing Yimin New Materials Technology Co., LTD., the company has newly developed a WSX-4000 super intelligent titanium dioxide high-temperature water washing integrated machine, which has been successfully put into operation at Shanghai Pengbo Titanium Dioxide Co., LTD. The online operation condition shows that the material temperature entering the filter tank is 90℃, and the production cycle of the first wash is ≤3.5 hours. Water consumption is ≤22m³/T(TiO2), daily production (TiO2) is 16T per unit, and the utilization rate of metasilicate is over 99%.

The filter tank of this integrated machine has a simple structure, stable performance, corrosion resistance and a long service life. The asymmetric rigid sintered membrane tube can effectively inhibit filtration and improve the utilization rate of raw materials. Automated production reduces the labor intensity of workers and improves the production environment. The filter medium cannot be cut or broken and is easy to clean. Filtration does not require filter AIDS, and cleaning does not use hydrofluoric acid. Remote data transmission enables professional engineers to achieve full-process management such as parameter modification, fault diagnosis and data traceability through remote terminals, providing 24-hour service for production. Compared with the traditional sulfuric acid method titanium dioxide water washing equipment, this integrated machine has three innovative points. First, it adopts deep filtration technology, which improves the filtration accuracy and suppresses the perforation. Second, by adopting PLC control technology, the automated production of titanium dioxide water washing has been achieved. Thirdly, the closed water washing process was adopted, achieving clean and civilized production.

Wu Zhengming stated that this technical equipment has overcome the technical difficulties in manufacturing titanium dioxide water washing equipment, enabling the water washing machine to not only withstand high-temperature water washing but also fulfill the industry's long-awaited aspirations for water washing automation and improvement of the production environment, among others. It will become a new benchmark for green titanium dioxide water washing in the titanium dioxide industry.

Feng Pingcang, the chairman of Sichuan Ruichi Tuowei Technology Co., LTD., pointed out that most of the sand mills used for the post-treatment of titanium dioxide with an annual output of about 6 million tons in China are provided by this company. In 2001, Longwang Titanium Industry, a Chinese titanium dioxide producer, introduced foreign sand mills for the first time. At that time, the price of an imported 1,000-liter sand mill was about 3.5 to 4.5 million yuan. The high price and the lack of timely spare parts and after-sales service seriously restricted the expansion of titanium dioxide production in China. To solve technical problems, Sichuan Ruichi Company has continuously carried out scientific research and technological breakthroughs, successfully developing domestic large-scale HDM+HTM series sand mills. The price has gradually dropped from over 3 million yuan per unit 25 years ago to over 1 million yuan per unit now. Not only has the price of the equipment dropped by three times, but its technological advancement has also surpassed that of imported equipment.

Feng Pingcang emphasized that this was mainly attributed to the company's thorough resolution of two key issues: the mechanical seal of the sand mill and the material of the components in contact with the materials. Sichuan Ruichi Company successively established research and development departments for mechanical seals and high molecular materials, which reduced the failure rate of mechanical seals from 30% to 0.1% and extended the service life of grinding discs from one year to 12 years. It is particularly worth mentioning that the company has developed a special polymer material suitable for the production of titanium dioxide by the chloride process, which is highly resistant to chloride ion corrosion and hydrogen peroxide oxidation, completely solving the bottleneck problem in the production of titanium dioxide by the chloride process. Nowadays, almost all the post-treatment sand mills for titanium dioxide produced by the chlorination and hydrochloric acid processes in China are provided by Sichuan Ruichi Company.

Feng Pingcang said, "There's no way out in the process of internal competition!" A price war is a lose-lose situation for both production equipment enterprises and their customers. Traditional manufacturing is like winter, high-end manufacturing is like autumn, and advanced manufacturing is like spring. Increasing investment, cultivating talents, and conducting forward-looking research and development of new technologies, new materials, new processes, and new equipment are the only ways out for the manufacturing industry. The company's newly developed new-generation superheated steam pulverizer for post-treatment of titanium dioxide uses special wear-resistant materials, which greatly extends its service life and is highly favored by enterprises in the titanium dioxide industry.

Wang Xijian, the general manager of Xiangtan Huibo Centrifuge Co., LTD., introduced that the company's newly launched pusher centrifuge and sedimentation filtration centrifuge under new process conditions can be used for the separation of suspensions with solid content of crystalline particles ranging from 5% to 50%. They are integrated thickening and filtration equipment featuring screw sedimentation, screw filtration, thin-layer separation, and centrifugal filtration. It features continuous sedimentation + centrifugal filtration, no foundation installation, one-time separation of crystalline titanium solution, ferrous sulfate washing function, separate discharge of settled titanium solution and filtered titanium solution, and separate discharge of washing liquid and titanium solution. It has been widely applied in numerous titanium dioxide industry factories.

The viscosity of the ferrous sulfate slurry from the waste acid concentration process is relatively low, and a cantilevered supported structure sedimentation and filtration integrated machine can be used for continuous separation. The slurry containing ferrous sulfate enters the screw conveyor through the feed pipe and is accelerated in the distribution chamber, then evenly distributed into the sedimentation drum. Under the action of centrifugal force, the heavier solid phase (ferrous sulfate) particles in the suspension rapidly settle on the wall of the sedimentation drum to form annular sediment, while the lighter liquid phase forms an annular liquid layer on the annular sedimentation. Black titanium hydraulic suspension is continuously added through the feed pipe. Let the lighter pure titanium liquid overflow from the overflow port at the bottom of the drum. Due to the differential speed between the screw conveyor and the drum, the sediment is conveyed by the screw conveyor to the filter direct drum for further dewatering and then pushed to the filter cone drum for further dewatering. Finally, it is discharged from the filter cone drum and collected in the collection trough before being discharged outside the machine. A flushing pipe is designed on the machine door cover, which can flush the ferrous sulfate in the filter drum section. The liquid phases discharged from the sedimentation drum and the filtration drum are respectively collected by the casing and discharged outside the machine. Clear mother liquor is obtained in the sedimentation section. The filtration section recovers solids with extremely low moisture content. The mother liquor from the sedimentation section and the filtration section is collected completely separately, and the centrifugal filtration effect is more significant.

Wang Xijian stated that over the years, the company has been committed to serving customers with dedication. While achieving development results, it has also earned a good reputation and word-of-mouth, becoming a high-quality supplier of centrifuge equipment in the titanium dioxide industry and making positive contributions to the high-quality and healthy development of the industry.

Xie Guoquan, the chairman of Hunan Yifeng Anti-corrosion Engineering Co., LTD., introduced that as a supporting service enterprise in the titanium dioxide industry, it is a large-scale comprehensive professional anti-corrosion construction unit integrating multiple project construction. It holds the national first-class anti-corrosion construction qualification and is a national high-tech enterprise, a specialized, refined, distinctive and innovative "little giant" enterprise in Hunan Province, an innovative small and medium-sized enterprise in Hunan Province, a national AAA-level trusted certification enterprise in anti-corrosion engineering, a star anti-corrosion construction enterprise in Hunan Province, one of the top 100 anti-corrosion engineering enterprises in China, and a "craftsman spirit" enterprise in the Chinese anti-corrosion industry. The company has always adhered to the path of integrating scientific research and development with application, and has successively obtained a number of national invention patents. It has developed several new anti-corrosion processes, technologies and products. In particular, the corrosion-resistant rubber-lined high-pressure centrifugal fan has been widely applied in phosphorus fertilizer fluorine exhaust fans, phosphorus ammonium tail gas ventilators, titanium dioxide tail gas ventilators, etc., and has received unanimous praise from users. The developed KPI acid-resistant mortar, PE(PO) lining anti-corrosion technology, polyurea spray anti-corrosion technology, high-performance glass flake lining anti-corrosion technology, epoxy self-leveling construction technology, etc. all have relatively advanced technical levels and are widely applied in the titanium dioxide industry.

Xie Guoquan stated that Hunan Yifeng Anti-corrosion adheres to the tenet of "honesty and service", and takes "producing high-quality materials and creating excellent projects" as its quality policy. It has been making unremitting efforts to comprehensively control corrosion and protect the industry. Relying on its original technological advantages, it contributes Yifeng Anti-corrosion's strength to the healthy development of the titanium dioxide industry.