A lime slaking system is mainly used in applications with high lime consumption. Typical areas of application for lime slaking plants are sewage treatment plants with a large size class (capacity in population equivalent) or wet scrubbers in flue gas desulfurization.
In these applications, which have a greater need for milk of lime, it is more economical for the operator to slake the lime in their own lime slaking plants. Depending on the general conditions, this threshold is reached at approx. 500 tons/year of lime consumption.
For applications with low lime consumption, the preparation of milk of lime from hydrated lime is often the more economical option.
In the first step of the process, the quicklime ( CaO ) is stored in a silo or big bag and fed to the lime slaking tank via a volumetric Sodimate discharge and dosing unit and an injector ID for lime, PAH, sodium bicarbonate and other products. There it is quenched with water in an exothermic reaction and made into a highly concentrated solution (25-30%). The lime slaking tank can be made of steel or stainless steel and is equipped with a protection against accidental contact.
A temperature probe monitors the extinguishing temperature.
When the unslaked lime is slaked and prepared, vapors are produced which consist of small lime particles and water vapor (temperature approx. 50° – 80°C).
In conjunction with the vapor scrubber (wet separator), the system works dust-free.
In the second process step, the dilution to your desired final concentration takes place. The milk of lime produced in the lime slaking tank overflows into the storage tank, where it is kept in suspension by constant stirring and diluted to the desired concentration by adding dilution water. The milk of lime can then be removed continuously or in batches.