Method of increasing the surface area and plastic properties of hydrated lime

A method for producing a controlled temperature lime hydrate especially suited for use as a plasticizer in mortar compositions, the lime hydrate being characterized as having a surface area in excess of 50 m.sup.2 /g and as having particles in the shape of thin, flat platelets, the method comprising the steps of:

• combining water and quicklime in a slaking operation within a hydrator vessel to thereby form a lime hydrate the water to quicklime ratio being in the range from 2.0:1 to 3.0:1, so that the resulting lime hydrate is a wet product having a percent solids ranging from about 40 to 55%, the step of combining the water and quicklime producing an exothermic chemical reaction which, in turn, produces a heated water of hydration, the quicklime including oxide components having highly active oxide sites;
• the slaking operation being carried out int he presence of a chemical modifier selected from the group consisting monoethanolamine, diethanolamine, triethanolamine and mixtures thereof, the chemical modifier to quicklime ratio being in the range from 0.003:1 to 0.040:1, the chemical modifier being present in an amount effective to control the heat of the heated water of hydration sufficiently to prevent the formation of steam by blocking the highly active oxide sites and delaying the reaction, whereby a hydrated lime particle results having a particle size in the range from about 0.2 to 0.35 microns, having a surface area in excess of 50 m.sup.2 /g and having particles shaped as thin, flat platelets.

A method of increasing the surface area and plastic properties of hydrated lime, the method comprising the steps of:

• providing as a starting material a quicklime selected from the group consisting of high calcium lime and dolomitic quicklime;
• slaking the quicklime with water in the presence of a chemical modifier, the chemical modifier being selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, monoethanolamine, diethanolamine, triethanolamine and mixtures thereof, the chemical modifier being present in an amount effective to control the heat of hydration sufficiently to prevent the formation of steam;
• and
• producing a hydrated lime putty as a result of the slaking, the putty comprising about 40% to 55% solids and hydrated lime particles having a particle size in the range from about 0.2 to 0.35 .mu.m, a surface area in excess of 20 m.sup.2 /g and shaped as thin, flat platelets.