The invention relates to a process for the wet milling of slag, wherein more than 100 kWh of milling energy are introduced per metric ton of slag and the weight ratio of slag to water is 0.05-4:1 and from 0.005 to 2% by weight, based on the slag, of a milling auxiliary which comprises at least one compound selected from the group consisting of polycarboxylate ether, phosphated polycondensation product, lignosulfonate, melamine-formaldehyde sulfonate, naphthalene-formaldehyde sulfonate, monoglycols, diglycols, triglycols and polyglycols, polyalcohols, alkanolamine, amino acids, sugar, molasses and curing accelerators based on calcium silicate hydrate is added to the material being milled before or during the milling.

Disclosed is a composite gypsum board comprising a board core comprising set gypsum sandwiched between face and back cover sheets. The composite gypsum board also comprises an intermediate sheet between the board core and the face cover sheet, with a thin, dense gypsum layer disposed between the intermediate sheet and the face cover sheet. Optionally, a second dense gypsum layer can be disposed between a first major side of the board core and the back cover sheet. Also disclosed is a method of preparing a composite gypsum board in which an intermediate sheet is applied over a dense gypsum layer disposed on a face cover sheet. A back cover sheet is applied to the other major side of the board core, with a second dense gypsum layer optionally disposed therebetween.

Disclosed is a composite gypsum board comprising a board core comprising set gypsum sandwiched between face and back cover sheets. The composite gypsum board also comprises an intermediate sheet between the board core and the face cover sheet, with a thin, dense gypsum layer disposed between the intermediate sheet and the face cover sheet. Optionally, a second dense gypsum layer can be disposed between a first major side of the board core and the back cover sheet. Also disclosed is a method of preparing a composite gypsum board in which an intermediate sheet is applied over a dense gypsum layer disposed on a face cover sheet. A back cover sheet is applied to the other major side of the board core, with a second dense gypsum layer optionally disposed therebetween.

A foamed lightweight monolithic refractory castable is provided. The castable includes one or more refractory aggregates as a main constituent, one or more foaming additives in a range of 0.1 wt % to 3.0 wt %, one or more cellulosic powder air-entraining additives in a range of 0.005 wt % to 2.0 wt %, one or more binders in a range of 1 wt % to 40 wt %, and one or more superplasticizers in a range of 0.05 wt % to 0.5 wt %. The refractory aggregates include at least one of alumina and silica. The foaming additives include at least one of alkylbenzene sulfonates, alkene sulfonates, and hydroxylalkane sulfates. The superplasticizers include at least one of sodium polyacrylates, naphthalene sulfonates, polyethylene glycols, polycarboxylates, polyacrylates, and polycarboxylate ethers.

A foamed lightweight monolithic refractory castable is provided. The castable includes one or more refractory aggregates as a main constituent, one or more foaming additives in a range of 0.1 wt % to 3.0 wt %, one or more cellulosic powder air-entraining additives in a range of 0.005 wt % to 2.0 wt %, one or more binders in a range of 1 wt % to 40 wt %, and one or more superplasticizers in a range of 0.05 wt % to 0.5 wt %. The refractory aggregates include at least one of alumina and silica. The foaming additives include at least one of alkylbenzene sulfonates, alkene sulfonates, and hydroxylalkane sulfates. The superplasticizers include at least one of sodium polyacrylates, naphthalene sulfonates, polyethylene glycols, polycarboxylates, polyacrylates, and polycarboxylate ethers.

A downhole tool comprising a cylindrical housing, a sleeve disposed in the cylindrical housing, forming an annular space between the sleeve and the cylindrical housing, and a tool cement composition disposed in the annular space, wherein prior to setting the tool cement composition comprises a cement, sand, a silicon-containing material, a dispersant, and water, and wherein upon setting the tool cement composition provides an annular seal having a fluid leakage of less than 750 ml over 15 minutes at a pressure of 7500 psi and a temperature of 400° F.

A downhole tool comprising a cylindrical housing, a sleeve disposed in the cylindrical housing, forming an annular space between the sleeve and the cylindrical housing, and a tool cement composition disposed in the annular space, wherein prior to setting the tool cement composition comprises a cement, sand, a silicon-containing material, a dispersant, and water, and wherein upon setting the tool cement composition provides an annular seal having a fluid leakage of less than 750 ml over 15 minutes at a pressure of 7500 psi and a temperature of 400° F.

A set control composition for cementitious systems comprises (a) an amine-glyoxylic acid condensate, and (b) at least one of (i) a borate source and (ii) a carbonate source. The carbonate source is selected from inorganic carbonates having an aqueous solubility of 0.1 gL.sup.−1 or more, and organic carbonates. The set control composition improves workability of cementitious systems for prolonged periods of time without compromising early compressive strength. Due to the retarding action of the set control composition, the dosage of dispersant(s) necessary to obtain a desired flowability of the cementitious system can be reduced.

A set control composition for cementitious systems comprises (a) an amine-glyoxylic acid condensate, and (b) at least one of (i) a borate source and (ii) a carbonate source. The carbonate source is selected from inorganic carbonates having an aqueous solubility of 0.1 gL.sup.−1 or more, and organic carbonates. The set control composition improves workability of cementitious systems for prolonged periods of time without compromising early compressive strength. Due to the retarding action of the set control composition, the dosage of dispersant(s) necessary to obtain a desired flowability of the cementitious system can be reduced.

A dispersant composition includes a) at least one polymer constituted of monomers having naphthalene ring and/or melamine; b). at least one polymer having carboxylic acid and/or phosphoric acid group and/or any group that is hydrolyzed into carboxylic or phosphoric; and c). at least one polymer having a structure of Formula I:

##STR00001##

R.sup.1 is hydrogen or alky group having carbon number not less than 1, cycloalkyl or cycloalkenyl group having carbon number not less than 3, alkenyl group having carbon number not less than 2, aryl group having carbon number not less than 6; R.sup.2 is hydrogen or alky group having carbon number from 1 to 3; A is alkylene group having carbon number from 3 or 4; m and n are positive numbers wherein m is more than n and the sum of m and n is more than 9 and less than 12. Also provided is a method of using the dispersant composition in a mortar or concrete, and the weight percentage of the dispersant composition is from 0.01% to 2.5% based on the weight of cement in mortar. Further provided is an aqueous composition including the dispersant composition.