EZ-Brine™

Sulphate in Depleted Brine

The purpose of the EZ-Brine™ Sulphate is to optimize the brine recovery process, and guarantee brine purity for proper membrane operation.

Background

Sulphate ion concentration has become very important in the ultrapurified brine feed to the membrane cells, especially as the membranes are improved in order to increase performance. A typical feed brine sodium sulfate (Na2SO4) specification for membrane-type chlorine production cells is 4.73 g/L. About 50% of the sodium chloride fed to the membrane cells is converted and the other 50% exits from the cells as depleted brine containing the sodium sulphate that was in the original cell brine feed. The depleted brine is re-saturated, treated and returns back to the membrane cells, this means new calcium sulphate will be dissolved. In this way the total sulfate concentration will keep increasing with each recycle step.

With no escape from the brine loop, any amount of sulphate in the incoming salt or brine will eventually built up to the point where the concentration is violated. Once the Na2SO4 concentration of the brine exceeds 7.0 g/L, the sulfate will have an impact on cell efficiency and membrane life.

Other configurations

The EZ-Brine™ mainframe is also available in the following configurations: calcium and magnesium in ultrapurified brine, calcium and magnesium in prepurified brine, silica in ultrapurified brine, aluminium in ultrapurified brine, active chlorine in depleted brine, metabisulphite in depleted brine.