SULFATE REMOVAL

The Sulfate Removal Unit is designed to physically control sulfate accumulation in chlor-alkali brine loops without introducing barium-based chemicals.

SRU Series
Nanofiltration sulfate Removal Unit

Reliable Sulfate Control without Barium Addition

In membrane chlor-alkali plants, sulfate can gradually accumulate in the recycled brine circuit through salt impurities and process chemical additions. If not properly controlled, elevated sulfate levels may affect brine quality and increase the risk of deposits or contamination within the membrane-cell system.

Traditional sulfate removal methods commonly rely on chemical precipitation using barium chloride, converting dissolved sulfate into barium sulfate solids. Although effective, this process requires the handling of hazardous barium chemicals and generates additional chemical sludge for treatment and disposal.

The EFLUXERA SRU Series provides an alternative solution based on selective nanofiltration membrane technology. Instead of introducing barium salts into the brine circuit, the SRU removes sulfate through physical membrane separation, helping plants reduce chemical handling, secondary waste generation and unnecessary sodium chloride losses.

How the SRU Works?

The SRU treats a controlled side stream of dechlorinated depleted brine from the chlor-alkali process. Under pressure, the brine passes through specially selected nanofiltration membranes:

• sulfate ions (SO₄²⁻) are preferentially retained and concentrated in the reject stream.
• Sodium and chloride ions (Na⁺ and Cl⁻) largely pass through the membrane and are returned to the brine system.
• The treated low-sulfate brine can be recycled for resaturation and reuse in the production process.

This selective separation removes sulfate while retaining valuable sodium chloride within the production loop.

Key Benefits

Economically — The operating cost is only 20% or even less of the barium using.

No Barium Addition — Removes sulfate without introducing barium chloride into the brine circuit.

Reduced Chemical Handling — Avoids routine storage, dosing and safety management associated with hazardous barium chemicals.

Lower Secondary Waste — Reduces the formation of barium sulfate sludge requiring treatment and disposal.

Improved Brine Management — Controls sulfate accumulation while retaining most sodium chloride for reuse.

Downstream Protection — Helps maintain a stable brine composition for membrane-cell operation.

Cleaner Production Route — Supports reduced chemical consumption and more sustainable plant operation.

Selective Ion Separation by Nanofiltration

Nanofiltration is particularly suitable for sulfate control in recycled brine systems because it preferentially rejects divalent sulfate ions while allowing most monovalent sodium and chloride ions to pass through the membrane. This makes it possible to remove sulfate efficiently while minimising valuable salt loss.

EFLUXERA SRU Solutions

The EFLUXERA SRU Series is engineered for sulfate removal from depleted or diluted brine in membrane chlor-alkali plants. Each system can be configured according to feed composition, required sulfate reduction, plant capacity and integration requirements.

Typical Scope of Supply

<<Pretreatment Skid

<<Nano-filter Skid

<<Chemical Dosing Skid