Tech company finds profit in coal waste

Workers use advanced mining equipment to extract coal from an open pit at the Pingshuo Antaibao Coal Mine in Shanxi province. (Zhangyi/China Daily)

A technology company in Shanxi province is pioneering the transformation of coal waste into valuable industrial materials, offering a solution to a mounting environmental challenge.

Shanxi Bright Kaolin Technology Corp, located in a major coal-producing region, has developed a technique to manufacture kaolin, a white clay mineral, from coal gangue — a byproduct of coal mining that creates environmental problems.

Coal gangue not only occupies land but also pollutes the air through sulfur emissions and poses a risk of spontaneous combustion. In Shanxi alone, coal gangue storage has reached 900 million metric tons, with its output accounting for 18 percent of coal production.

"Coal gangue is mainly utilized for low-value purposes in China," said Wu Qiang, a national political adviser and professor at the China University of Mining and Technology (Beijing). "Despite a national utilization rate exceeding 70 percent, it's primarily used in building materials, combustion and road paving."

The new technology offers a solution, transforming waste into valuable products.

"We've achieved breakthroughs in manufacturing coating kaolin and high-performance coal-based kaolin with exceptional porosity from coal gangue," said Li Yunxia, deputy director of the company's technology center. "Our products boast a large surface area, high oil absorption and strong coverage, meeting international standards."

Through a multi-step process including crushing, grinding, drying and calcination, the company produces ultra-fine kaolin particles exceeding 8,000 mesh — 100 times finer than flour. These particles possess valuable properties like wear resistance, moldability, fire resistance and electrical insulation, making them ideal for various industries such as coatings, aerospace, ceramics and wiring.

Shanxi Bright Kaolin consumes 600,000 tons of coal gangue annually, producing 500,000 tons of ultra-fine kaolin exported to over 40 countries.

"The strong export performance is a testament to the high quality of our coating products," said Yan Hongguang, a senior engineer at a partnering coating company. "While kaolin makes up only 5 to 10 percent of raw materials, its quality significantly impacts the final product."

Recognizing the company's innovation, Shanxi designated the comprehensive utilization industry chain for abandoned resources as a key provincial chain in 2023. Shanxi Bright Kaolin was chosen to lead resource integration and industrial development within this chain.

"We plan to increase investment in research and development, coordinate the development of upstream and downstream sectors, and upgrade the entire industry chain to contribute to the province's high-quality development," said company head Luo Xunqiao.