Glass-reinforced plastic (GRP) is prevailing over traditional concrete, steel and wood as the most suitable primary cooling tower material in mining processes involving aggressive chemical solutions.
Says Roger Rusch, CEO of IWC, “Over the past 30 years, GRP materials have been utilised as secondary components in cooling towers, such aspipes and fan stacks, with the primary structure constructed out of concrete, steel or wood. However, in chemical extractionprocesses,GRP’s inherent corrosion, moisture and temperature resistance significantly increases the durability and service life of the cooling tower structure, as well as reducing the need for maintenance; making it the primary material of choice today.”
Concrete cooling towers are reinforced with steel or other metals that, over time, corrode from constant exposure to aggressive chemicals. When the embedded metal corrodes, the resulting rust occupies a greater volume than the metal, creating tensile stresses and eventually causing cracking, delamination, and spalling.
Another reason for the corrosion of the cooling tower reinforcement in a chemical refinery is the existence of chlorides, which penetrate the passive layer of oxides and cause corrosion in the form of acupuncture.
Says Rusch, “In contrast, GRP cooling towers are resistant to galvanic and electrolytic corrosion and can withstand continuous contact with aggressive chemicals. This makes them an obvious choice in refineries wherehighly aggressive cell electrolyte and hot, purified chemical sulphates need to be cooled at a constant operating temperature.”