On June 28, 2025, the first domestic large-scale desulfurized gypsum and electrolytic manganese slag-based sulfuric acid production line—part of a national solid waste recycling demonstration project and contracted by HCRDI for Huaxia Special Steel Co., Ltd.—was fully put into operation.

Desulfurized gypsum and electrolytic manganese slag are by-products of flue gas desulfurization in coal-fired power plants and electrolytic manganese production, respectively. Traditionally, these materials have been disposed of mainly through stockpiling, which can easily cause environmental pollution. HCRDI developed an innovative sulfuric acid production technology that uses a specific ratio of desulfurized gypsum and electrolytic manganese slag as the primary raw materials, supplemented by several other solid wastes and reducing agents. Through processes such as calcination and high-temperature decomposition, the system produces sulfuric acid with 98% concentration—truly turning “waste into value.” This technology not only solves solid waste disposal challenges but also enables an annual sulfuric acid output of 800,000 tons, delivering significant economic and environmental benefits.

The project’s operational indicators rank among the best in the industry, with key energy consumption metrics outperforming design targets. “The successful commissioning of this project verifies the reliability of the domestically developed technical route and provides a mature model for large-scale application across the industry,” said the project’s technical director.

As China’s first full-industry-chain desulfurized gypsum-to-acid project, it is expected to reduce carbon dioxide emissions by 250,000 tons annually and save 1 million tons of pyrite resources. The application and promotion of this technology will greatly reduce the sulfuric acid industry’s dependence on traditional sulfur and pyrite, offering a replicable “Ningxia Green Development Solution” for high-energy-consuming sectors such as steel, power generation, and chemicals.