Membrane Sulfate Removal for Chlor-Alkali Brine

In 2026, Jiuwu Hi-Tech has reported a series of successes in the field of membrane sulfate removal, successively winning the bid for a waste salt comprehensive utilization project with 200,000 t/a ion-exchange membrane caustic soda in Chongqing, and a membrane sulfate removal unit (Tiandong plant + Indonesia plant) for a 300,000 t/a caustic soda project in Guangxi. The consecutive landing of these two orders is not only market recognition of the company's technical strength, but also a sign that its membrane sulfate removal technology is moving from domestic benchmark projects to synchronized domestic and overseas output, with international replication capability validated once again.

Industry Pain Points: Bottlenecks of Conventional Sulfate Removal

The ion-exchange membrane electrolyzer is the core equipment of the chlor-alkali industry, and the industry requires sulfate concentration in brine entering the cell to be below 5 g/L. Exceeding this level corrodes electrodes and ion membranes, reduces current efficiency, pushes up power consumption, and the damage is cumulative and hidden, easily causing irreversible economic losses.

Existing sulfate removal processes each have shortcomings:

Mainstream barium method - Low investment and good results, but barium chloride is highly toxic, with high safety and environmental risks; hazardous waste disposal drives up costs, and introduced metal impurities damage the ion membrane.

Freezing method - Introduces no impurities and has low operating costs, but requires harsh operating conditions and offers limited sulfate removal depth.

Conventional organic membranes - Highly dependent on raw salt quality; calcium and magnesium fluctuations easily cause system upset, forcing enterprises to purchase expensive high-quality salt and sharply increasing raw material costs.

Technical Breakthrough: "Pre-treatment + Nanofiltration Salt Separation"

Facing industry pain points, Jiuwu Hi-Tech has launched a complete membrane sulfate removal package of "pre-treatment + nanofiltration salt separation", using differences in nanofiltration membrane rejection rates for different ions to achieve efficient sulfate separation, forming five major technical advantages:

1. Simplified and energy-saving process - A combined process of standard nanofiltration plus high-pressure nanofiltration is developed, with fewer equipment items and smaller footprint; sodium sulfate concentration in high-sulfate water reaches 140-160 g/L and sodium chloride recovery exceeds 50%, reducing energy consumption in subsequent salt separation.

2. Stable and controllable operation - Membrane separation uses a single-pump design, combined with automated pre-treatment control, greatly improving the system's resistance to fluctuations.

3. Excellent salt cake quality - Combined with low-temperature crystallization, salt cake crystals are large and settle easily, solving the industry's chronic "floating salt cake" problem.

4. Durable equipment at low cost - Inorganic ceramic membranes resist acids, alkalis and oxidation, with a service life of over 10 years; the titanium-bodied filter has an overall life of more than 20 years, solving the problems of easy corrosion and frequent shutdowns in conventional equipment.

5. Intelligent unattended operation - A PLC automatic control system coordinates each process stage; the unit is compact with a small footprint, ensuring long-term stable operation.

Case Validation: Benchmark Projects at Home and Abroad

Domestic

In January 2026, the company won the bid for a waste salt comprehensive utilization project with 200,000 t/a ion-exchange membrane caustic soda in Chongqing. Membrane sulfate removal serves as the core purification unit for producing chlor-alkali from waste salt, responsible for removing sulfate from brine and ensuring stable operation of the electrolysis system, fully confirming the owner's high recognition of Jiuwu's complete equipment delivery capability.

Overseas

A chemical project in Guangxi adopted a packaged tender model of "Tiandong plant + Indonesia plant" membrane sulfate removal units with synchronized construction at both sites, promoting the replication of Jiuwu technical standards to overseas production bases. The company also won the bid for a 420,000 t/a caustic soda project in Indonesia, supplying complete ceramic membrane brine purification and nanofiltration sulfate removal equipment, with a ten-million-level order successfully delivered, demonstrating technical competitiveness.

Currently, Jiuwu's membrane sulfate removal process has been implemented in Egypt, Indonesia, India, Vietnam, Kazakhstan and other countries, with the overseas business footprint continuing to expand and international replication capability continuously confirmed by the market.

Full-Chain Layout: From Single Champion to Full-Process Solution

Jiuwu Hi-Tech is one of the few enterprises in China mastering both ceramic membrane and organic membrane core technologies, with a full range of spiral-wound membrane products covering UF, NF and RO. In the chlor-alkali industry, its inorganic membrane filters for primary brine purification have an installed scale of over 22 million tons, with a market share of 42%, forming a full-process capability of "ceramic membrane primary purification + nanofiltration sulfate removal + membrane concentration brine reuse".

Its ceramic membrane process has been implemented in nearly 200 chlor-alkali projects worldwide, supporting caustic soda capacity of more than 24 million tons per year; after treatment, suspended solids in refined brine are below 0.5 ppm and calcium and magnesium content below 1 ppm, far better than industry standards; in the brine reuse stage, concentrate recovery exceeds 60%, effectively reducing operating costs.

From materials to equipment, from purification to reuse, Jiuwu Hi-Tech drives the chlor-alkali industry toward data-driven and resource-circulating transformation with full-process solutions.