Abstract: A method of controlling the deposition of silica-containing scales and their adhesion to surfaces in contact with an aqueous system is disclosed which comprises adding to the aqueous system a synergistic combination of:(a) diethylenetriamine penta methylene phosphonic acid; and(b) a material selected from the group consisting of 2 phosphonobutane-1,2,4-tricarboxylic acid; high molecular weight, 3:1, acrylic acid/allylhydroxypropylsulfonate ether copolymer; ethylene oxide-propylene oxide block copolymers; and polyepoxysuccinic acid and salts thereof.

Abstract: A foam generating apparatus and system for generating high quality foam suitable for dust control is disclosed. The apparatus is an eductor that makes use of the energy of a high pressure stream of aqueous foaming solution to draw air into the foaming solution and force it through a foam generator. A dust control foam system is described which employs such air eductors. The described foaming system requires only a single pressurized line to supply foaming solution obviating the need for a compressed air line.

Abstract: Method for inhibiting dust emissions from hot (>150.degree. F.) substrates are provided which comprise adding to the substrate an aqueous solution of sodium silicate.