Michael Standish of Radical Polymers and Dr Michael Singh of Eye-Dale , present RPX-3546
WATER TREATMENT
A new copolymer for multifunctional applications
Michael Standish of Radical Polymers and Dr Michael Singh of Eye-Dale , present RPX-3546
Back in 2015 , carboxylate , sulfonate and / or non-ionic monomers represented the overwhelming majority of building blocks utilised to manufacture polymers for mineral scale control . 1 Mineral scale control was rarely needed in cooling water applications , due to the use of hexavalent chromium or chromate ( Cr 6 + ) for mild steel corrosion control .
Using Cr 6 + meant an essentially worry-free approach to controlling mild steel corrosion while operating at a circulating water pH of 6.0-7.0 to avoid mineral scale formation . Polymers , when needed , were used simply to move solids in the system
Figure 1 - Calcium phosphate stabilisation – AA : AMPS copolymers or when sulfuric acid addition for pH control was sufficient to cause supersaturation and the precipitation of calcium , barium or strontium sulfate .
Generally , low molecular weight ( MW ) polycarboxylates , such as polyacrylic and polymaleic acids with average MWs of < 3,000 Da respectively , are highly effective as sulfate inhibitors , while polyacrylic acids and polymethacrylic acids with MWs of 4,500-30,000 Da are highly effective for dispersion and solids control .
The use of Cr 6 + in cooling water began to be eliminated in the 1970s and has been fully restricted since 1990 . This and the general ability to operate systems at neutral or lower pH ranges has transformed how cooling water is treated and created a need for other corrosion inhibitors and additional polymer functionalities .
Now , higher circulating water pH ranges are necessary to mitigate mild steel corrosion potential while strongly increasing the potential for mineral scales , such as calcium carbonate ( CaCO 3
) and calcium phosphate Ca 3 ( PO 4
) 2
. The key point here is that when Cr 6 + was eliminated ,
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