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Precipitation

Reduction of heavy metals and other ions

Metals do not degrade in the environment. They can be very toxic to humans and animals, therefore municipalities and industries must remove them from wastewater.

Chemical precipitation is the most common technology used to remove dissolved (ionic) metals from solutions, such as process wastewaters containing toxic metals. The ionic metals are converted to an insoluble form (particle) by the chemical reaction between the soluble metal compounds and the precipitating reagent. The particles formed by this reaction are removed from solution by settling and/or filtration.

The effectiveness of a chemical precipitation process is dependent on several factors, including the type and concentration of ionic metals present in solution, the precipitant used, the reaction conditions (especially the pH of the solution), and the presence of other constituents that may inhibit the precipitation reaction.

The most widely used chemical precipitation process is hydroxide precipitation in which metal hydroxides are formed by using calcium hydroxide (lime) as the precipitant. Each dissolved metal has a distinct pH value at which the optimum hydroxide precipitation occurs - from 7.5 for chromium to 11.0 for cadmium.

When considering the cost of precipitating agents and alkali requirements, lime is the most cost-effective option to remove metals from wastewaters.



Neutralac® solution

We answer to your needs of treated water with a series of lime-based reagents that produce a favorable precipitation environment. With these following Neutralac® reagents, metals form insoluble compounds that can successfully be retained from the treated wastewater.



Quicklime - Neutralac® Q

Hydrated lime - Neutralac® H

Liquid product - Neutralac® SL

Liquid product - Neutralac® SLS45


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