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EnglishNJ Sequoia Industrial: Customized & Reliable Technology for Sulfuric Acid Production via Coke Reduction of Gypsum (Phosphogypsum, Flue Gas Desulfurization Gypsum, Manganese Residue, Titanium Gypsum, Nickel-Cobalt Gypsum & Other Industrial Gypsum Wastes) with Co-Production of Calcium Oxide or Cement Clinker
I. A Breakthrough Solution Amid Surging Sulfur Prices and Mounting Solid Waste Pressures
In 2025, the global sulfur price kept soaring amid sharply rising demand for sulfuric acid, creating a stark supply-demand imbalance. Driven by rapid expansion across the new energy sector, the annual demand growth rate of sulfuric acid exceeded 18%, while the shift toward clean energy cut down conventional sulfur output. China’s reliance on imported sulfur remains above 60%.
Meanwhile, China generates over 300 million tons of industrial by-product gypsum annually. Stockpiling such massive volumes not only occupies millions of mu of land but also poses severe risks of groundwater contamination.
Against this backdrop, the coke reduction process for gypsum has emerged as a strategically vital technology, enabling dual recovery of sulfur and calcium elements through targeted chemical conversion: sulfate radicals in gypsum are converted into high-purity 98% sulfuric acid, while calcium is recovered as calcium oxide, which can be used as raw material for cement clinker or quicklime products. This approach resolves the crisis of accumulated industrial solid waste and establishes an internal circular system for sulfur resource supply.
This technology is listed as an encouraged project under Category XLII (Environmental Protection, Resource Conservation & Comprehensive Utilization) of the Catalogue for the Guidance of Industrial Structure Adjustment (2024 Edition). It is also designated as a core utilization route for phosphogypsum in the Solid Waste Comprehensive Treatment Action Plan, with sustained policy support for its industrial adoption.
II. Industrial Chain Transformation: From Isolated Cost Reduction to Eco-Chain Value Addition
The core competitive edge of this process lies in its synergistic full-industry-chain benefits that deliver multi-dimensional economic gains for enterprises:
Upstream Cost Stabilization
On-site gypsum-based sulfuric acid production eliminates total dependence on purchased sulfur. Taking Yuntianhua’s annual sulfuric acid demand of 6 million tons as a benchmark, adoption of this process can cut annual procurement costs by more than 3 billion RMB and insulate the enterprise from volatile international sulfur pricing.
Downstream Closed-Loop Value Enhancement
Co-produced calcium oxide can be directly recycled for neutralization in upstream production workflows, forming an internal circular loop: Gypsum-to-Sulfuric Acid → CaO Co-Production → On-Site Neutralization Reuse. This slashes expenditure on auxiliary raw materials and solid waste disposal simultaneously.
Regional Economic Driving Force
Large-scale facilities built in regions with abundant flue gas desulfurization gypsum reserves can stimulate growth in power generation, logistics, building materials and other associated industries, fostering a circular economy industrial park with an annual output value exceeding 5 billion RMB.
III. Sequoia Customized Solutions: Leading Technology & End-to-End Full-Lifecycle Services
As a technological pioneer in this sector, Sequoia has developed a complete process package covering gypsum drying, reduction, cooling and sulfuric acid synthesis, with proven capability in core equipment design and supply.
Industry-Leading Technical Indicators
Fully commissioned plants can process over 1 million tons of wet gypsum residues with an initial moisture content above 25% per year, yielding more than 360,000 tons of 98% concentrated sulfuric acid annually. The standard coal consumption of the calcination system is controlled below 220 kgce per ton of finished product, meeting internationally advanced benchmarks.
Comprehensive One-Stop Service Portfolio
We deliver turnkey support spanning process package development & handover, core equipment supply, and feasibility study report compilation to guarantee seamless project implementation throughout the entire lifecycle.
Benchmark International Cooperation
In December 2025, Sequoia entered a strategic partnership with a leading domestic nickel-cobalt enterprise to tailor a gypsum-to-sulfuric-acid-with-CaO-co-production project for its Southeast Asian base. The bespoke solution precisely addresses the base’s rigid demand for sulfuric acid in nickel-cobalt smelting while complying with stringent local emission and environmental regulations.
IV. Why Choose Sequoia: Decades of Practical Expertise to Secure Project Success
Sequoia’s core R&D and engineering team has over ten years of deep-rooted experience in gypsum resource recycling and has witnessed and driven major technological upgrades across the industry:
- Participated end-to-end in China’s first large-scale gypsum sulfuric acid & cement clinker co-production project for a top domestic manganese producer (initiated in 2012), pioneering the commercial large-scale application of this technology nationwide.
- Led the manganese residue desulfurization activation and sulfuric acid production project for the same leading manganese enterprise, which was fully commissioned and accepted in 2017 and has since become a national model for high-value utilization of industrial solid waste.
From the first domestic set of core process equipment to cross-border international projects, Sequoia consistently leverages technological innovation and field engineering experience to refine process design and specialized equipment, delivering cost-effective, high-performance engineering solutions for clients.
Our strategic collaboration with the leading nickel-cobalt group stands as definitive validation of our technical prowess and service reliability. Partner with Sequoia to build a robust foundation for sustainable growth within the circular economy landscape.
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