[Lessons from Others] Turning waste into resources: How technology generates benefits – A documentary on Lubei Chemical’s efforts in producing sulfuric acid from gypsum and titanium dioxide via the chlorination process 　

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There is an unavoidable problem in China’s phosphorus chemical industry: phosphogypsum. This by-product of phosphoric acid production has seen a cumulative national stockpile exceeding 800 million tons; each year, an additional 80 million tons are generated. Yet, the overall utilization rate has remained below 40% for a long time. The open-air stacking of large quantities of phosphogypsum occupies land, generates dust, and causes leachate to contaminate groundwater; this is widely regarded in the industry as an intractable problem. 　　Relying on two key technologies—the co-production of sulfuric acid and cement from gypsum, and the chloride process for titanium dioxide production—Shandong Lubei Enterprise Group General Corporation has provided a feasible solution to this “deadlock”. In the first quarter, Lubei Chemical, the group’s core listed company, achieved a net profit attributable to shareholders of 56.5559 million yuan, a year-on-year increase of 57.07%, thus generating favorable economic results. 　　From “waste residue” to a resource. In the 1980s, when most phosphate and compound fertilizer enterprises were still struggling to find uses for phosphogypsum, Lubei—which had just begun operations on the saline-alkali land along the Bohai Bay—set its sights on solving this problem. 　　“The main component of gypsum is calcium sulfate. Is it possible to decompose it into sulfur dioxide and calcium oxide? The former can be used to produce sulfuric acid, while the latter can be utilized in cement production; the sulfuric acid can then be reused in the production of ammonium phosphate.” In principle, this idea makes sense. However, no one knows for sure whether it can be implemented on an industrial scale. 　　After that came a long period of tackling challenges. Phosphogypsum contains a high amount of free water and has significant variations in composition; it easily causes blockages when dried in a kiln ； Even a slight fluctuation in the furnace atmosphere causes the decomposition rate to drop significantly. From the “Sixth Five-Year Plan” research efforts to the industrialization during the “Seventh Five-Year Plan”, and from scaling up during the “Eighth Five-Year Plan” to achieving full system integration in the “Ninth Five-Year Plan”, northern Shandong successfully developed the process of producing sulfuric acid and cement from gypsum, transforming it from a laboratory-scale procedure into a large-scale industrial operation. Subsequently, the relevant technology has successively won the **Second Prize of the Science and Technology Progress Award and the Silver Award of the China Patent Award. 　　In July 2025, the key technology for wet acid production, developed jointly by Lubei and Keyang Environment, passed the evaluation of scientific and technological achievements organized by the China Petroleum and Chemical Industry Federation. The evaluation panel concluded that this technology introduces a novel “one conversion, one cooling” process, enabling a single-pass conversion rate of sulfur dioxide exceeding 99.3% under conditions of high water vapor partial pressure, thus reaching international advanced levels. 　　Currently, the individual production units in northern Shandong have achieved integrated operation with an annual output of 400,000 tons of sulfuric acid and 600,000 tons of cement. They also recycle approximately 1 million tons of gypsum waste residue and 300,000 tons of waste sulfuric acid each year. Industrial by-product gypsum is continuously fed into the rotary kiln, while the produced sulfuric acid and cement are directly sold on the market. What was once waste has become an important resource in the circular economy chain. 　　Overcoming the ‘difficult challenges’ – If the use of gypsum in acid production resolved the ‘deadlock’ in the phosphate chemicals industry, then the breakthrough in titanium dioxide production via chlorination methods broke another ‘shackle’. 　　China is the largest producer of titanium dioxide, with an effective production capacity of around 5.7 million tons by 2025, accounting for over 50% of the global total. However, for a long time, the vast majority of domestic enterprises have followed the traditional sulfuric acid route – a process that is lengthy and energy-intensive, and one that generates large amounts of waste acid and red gypsum as by-products. The chlorination process, which boasts advantages such as short processing time, low energy consumption, and high product quality, has seen its core technologies monopolized by foreign entities for a long time. Moreover, the technical routes introduced to China in the early days have not fully achieved the expected results. 　　Northern Shandong resolved to tackle this \"tough nut\" by establishing a dedicated research institute, starting with the most fundamental oxidation-chlorination coupling reaction. Northern Shandong is home to chemical manufacturing enterprises that employ two highly hazardous processes: oxidation and chlorination; it is extremely difficult to find a balance between safety and efficiency in such situations. After countless experiments and repeated attempts, a technological breakthrough was finally achieved, bringing the team to a leading position. 　　In 2020, the first large-scale production facility was successfully commissioned for the first time, making Lubei one of the few companies in China at that time that possessed the technology for mass production using the chlorination method. Unlike other chlorination plants in China, which often suffer losses due to frequent start-ups and shutdowns, the plant in Northern Shandong operates continuously and stably, with advanced product specifications, enabling it to penetrate the high-end coating and electronics industries. 　　The synergy between the two technologies yields benefits. For northern Shandong, gypsum-based acid production and the chlorination method for titanium dioxide are not two separate technological innovations; rather, they are key components that are interconnected within the same circular economy industry chain. 　　Phosphogypsum, a by-product of phosphoric acid production, is used to produce sulfuric acid and cement; the sulfuric acid is then reused in the production of phosphoric acid and titanium dioxide ； The waste acid generated in titanium dioxide production is treated and then used in the production of phosphoric acid and titanium-rich materials. Phosphoric acid, together with the by-product ferrous sulfate, is converted into lithium iron phosphate, a raw material for new energy batteries, while the titanium-rich materials are used as raw materials for titanium dioxide production via the chlorination method. It is precisely this “sulfur-phosphorus-calcium-titanium-lithium” circular economy system that has helped northern Shandong keep its costs stable amid drastic fluctuations in raw material prices. 　　In the first quarter of this year, affected by geopolitical conflicts, the benchmark price of sulfuric acid rose from around 917 yuan per ton at the beginning of the year to around 2,100 yuan per ton by mid-April, an increase of nearly 130% ； The benchmark price of sulfur briefly reached 6,700 yuan per ton, hitting a record high. Numerous enterprises reliant on sulfur are experiencing cost reversals and even facing shortages of raw materials; meanwhile, the cost of producing sulfuric acid from gypsum in northern Shandong is significantly lower than that of the sulfur-based production route. During the same period, overall profits in the titanium dioxide industry declined by over 40%, yet titanium dioxide produced by the chlorination method in Northern Shandong managed to maintain its profitability thanks to high operation rates and superior quality. 　　Lv Tianbao, who rose from a technician to chairman, has been involved in almost all technological challenges. Looking back on over 40 years of experience, he said, \"Traditional industries are not backward industries; rather, they serve as an important foundation for fostering and developing new forms of productivity. Our goal is to turn legal constraints into opportunities for value creation.\" ”In recent years, environmental protection policies have become increasingly strict and emission standards more stringent. Lubei Group has turned these strict regulations into a driving force for green development, enabling the circular economy technology system to realize greater value. “Environmental protection isn’t a cost drain; it’s a competitive moat for industries. ”Lv Tianbao said.