Application 04
pH Correction and Neutralisation
Water that is too acidic corrodes pipes and fittings; acidic effluent must be neutralised before it can be discharged.
Quick answer
How does hydrated lime raise pH?
Hydrated lime is calcium hydroxide, an alkali. Dissolved in water it releases hydroxide ions, which raise the pH. At higher doses it also precipitates hardness as calcium carbonate and magnesium hydroxide.
How it works
Hydrated lime is calcium hydroxide, an alkali. Dosed as a slurry or solution, it raises the pH of the water or process stream.
At higher doses it precipitates hardness as calcium carbonate and magnesium hydroxide (lime softening), and it helps precipitate metals from effluent.
- 01
Prepare
Lime is mixed into a slurry or saturated solution.
- 02
Dose
Added to the stream with good mixing.
- 03
React
pH rises; hardness or metals precipitate if targeted.
- 04
Settle or filter
Precipitated solids are removed.
Product used for ph correction
What to consider
- Starting and target pH
- Softening or pH correction only
- Dosing and mixing equipment
- Handling and storage of the powder
Industries
pH Correction and Neutralisation: common questions
What pH is targeted in drinking water treatment?
The target depends on the water and the applicable standard. Drinking water is commonly kept within a range of about 6.5 to 8.5.
How should hydrated lime be handled?
Hydrated lime is alkaline and can irritate the skin, eyes and lungs. Use gloves, eye protection and dust control when handling the powder.
Discuss your ph correction requirement
Tell us about your application and requirements. Our team will help you identify the appropriate product for your needs.
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Drying and Moisture Control