NOVELTY - Preparing an aqueous suspension of calcium hydroxide, comprises (a) providing an aqueous solution, (b) providing powdered calcium hydroxide, (c) providing copolymer consisting of methacrylic acid monomers and/or its salts, optionally acrylic acid monomers and/or its salts and monomers (I), (d) adding at least one part of the amount of a copolymer to at least one part of an aqueous solution under stirring, (e) adding at least one part of powdered calcium hydroxide to the aqueous solution under stirring, and (f) applying a homogeneous shear level to the initial mixture.    USE - The method is useful for preparing an aqueous suspension of calcium hydroxide such as a hydrated lime, which is useful: for treating industrial flue gases, preferably for the desulfurization of flue gas or for the treatment of domestic wastewater, preferably drinking or industrial wastewater (all claimed); as a chemical neutralization agent; in household or industrial waste incineration plants to generate the sulfur and other impurities including acid molecules (sulfur dioxide, sulfur trioxide, sulfuric acid, hydrochloric acid and hydrofluoric acid) or pollutants (mercury and heavy metals); as mine effluent neutralizers for neutralizing acidity and/or separating heavy metals in solution before the discharge of fluids into the natural environment or into a lagoon; for water decarbonation processes and a process for temporarily reducing water hardness (partial or total elimination of alkaline earth metal bicarbonates); for the treatment of aggregates used in the bituminous coated material production process; for the production of aerated concrete type construction materials; in the treatment of contaminated soils to neutralize the acidity of these soils, to immobilize pollutants by neutralization or flocculation and to avoid the driving of such pollutants into the groundwater; in the treatment of soils in agriculture to correct the pH of these soils, improve the soils by providing a source of calcium or of calcium and magnesium in the case of dolomitic lime and to make these soils less impermeable by flocculation of clays; in the treatment of surface waters, lakes, ponds and rivers to adjust the pH of the water to reduce the impact of the acidification of these waters, preferably acidification of rain or animal origin in the case of fish farming; for the production of food for livestock or poultry; in the paper industry such as papermaking pulp; for refining sugar; and for the production of precipitated calcium carbonate, where the industrial flue gases are obtained from energy-producing plants.    ADVANTAGE - The concentrated and stable aqueous suspension of calcium hydroxide avoids the sedimentation during its storage with agitation, exhibits good rheology properties, and is easy to prepare.    DETAILED DESCRIPTION - Preparing an aqueous suspension of calcium hydroxide with a dry content of 40 wt.%, comprises (a) providing a determined volume of an aqueous solution, (b) providing a determined quantity of powdered calcium hydroxide, (c) providing a determined quantity of a copolymer consisting of methacrylic acid monomers and/or its salts, optionally acrylic acid monomers and/or its salts and monomers of formula (R-X-R1) (I), (d) adding at least one part of the amount of the copolymer to at least one part of the aqueous solution under stirring, (e) adding at least one part of powdered calcium hydroxide to the aqueous solution under stirring, (f) applying a homogeneous shear level of greater than 50000 s-1 to the initial mixture, and (g) optionally, while applying the shear level to the initial mixture, adding residual quantity of copolymer and/or powdered calcium hydroxide to the initial mixture. A viscosity of the aqueous suspension is 25-1000 mPa.s measured by a Brookfield DVIII viscometer at 10 revolution per minute at 20 degrees C.    R = polymerizable unsaturated group, preferably acrylate, methacrylate, methacrylurethane, vinyl or allyl;    R1 = H or 1-4C-alkyl;    X = structure with n units of ethylene oxide and m units of propylene oxide arranged randomly or regularly; and    m, n = non-zero integers or 1-150.    INDEPENDENT CLAIM is included for an aqueous suspension of calcium hydroxide obtained by the process.