(Waste) water treatment

Calcium chloride (CaCl2) is an inexpensive source of calcium ions and pH adjustment in wastewater treatment. Specific uses include treatment of oily wastes and the removal of various inorganic compounds, including fluorides, phosphates and heavy metals. Industries that use calcium chloride in wastewater treatment include aluminium, steel, metal finish­ing and electroplating, glass and ceramics, commercial laundries, and municipal wastewater.

Magnesium chloride (MgCl2) can be used as a Mg source for phosphate and ammonium removal in wastewater i.e. manure, municipal water treatment, wastewater-treatments of the food-processing industry. Phosphate can be precipitated by producing magnesium-ammonium-phosphate (struvite). Magnesium hydroxide (Mg(OH)2) can be used instead of magnesium chloride.
Magnesium chloride can also be used in combination with calcium hydroxide (Ca(OH)2) in non-sulfate containing waste streams. By adding magnesium chloride and calcium chloride, magnesium hydroxide is formed in situ, whereby contaminants (metals or organics) coprecipitate, enabling the re-use of process water.

Magnesium hydroxide: nedMag H is an aquous suspension of magnesium hydroxide. It reacts in a different manner and at a different rate compared to other alkalis. On technical and total cost basis it is an attractive alternative to other alkalis. There is a growing appreciation of the advantages magnesium hydroxide offers as an alkali for use in environmental control. Today, the need for more acceptable methods and products to neutralise acid waste has inspired industry to take a closer look at this different alkali.