Process for preparing detergent compositions containing hydrated inorganic salts

A continuous process for preparing a substantially hydrated detergent composition which comprises turbulently dispersing a feed of at least one hydratable detergent salt in particulate form in an inert gaseous medium, wetting the dispersed particles with an atomized stream of water or an aqueous alkali metal silicate metered to provide an amount of water sufficient to substantially hydrate the detergent salt, said metered amount of water constituting at least a stoichiometric amount but not in excess of about 20% over said stoichiometric amount for hydration of said salt and to cause the particles to agglomerate together to form agglomerates smaller than the sieve openings in a No. 8 U.S. Sieve Series, depositing the wet agglomerates in a closed container maintained at a temperature between at least 50.degree. C. and less than 100.degree. C. and retaining the agglomerates in said container while continuously gently stirring them to prevent formation of oversize agglomerates until the salt has been substantially hydrated to a degree of hydration between 70% and 100% of theoretical, removing the substantially hydrated salt agglomerates from said container and introducing them into a second zone of turbulence for dispersal in an inert gaseous medium while concurrently mixing therewith at least one or more members selected from the group consisting of non-ionic surfactants, anionic surfactants, cationic surfactants, neutral alkali metal salts, alkali metal hydroxides, solid chlorine releasing agents, alkali metal silicates, and anti-soil redeposition agents with the proviso that at least one member of the group upon being mixed with the hydrated salt agglomerates shall be in liquid form to provide sufficient wetting of the hydrated salt agglomerate surfaces for non-liquid solid members of the group to adhere to the hydrated salt agglomerate surfaces and to each other to form agglomerates of larger size but smaller than the sieve openings in a No. 8 U.S. Sieve Series, continuously depositing the resultant agglomerates in a hot air dryer and retaining them therein until their free-moisture content is less than 5 percent by weight.

A continuous process for producing a dry-pourable, non-caking detergent composition which comprises continuously feeding at least one hydratable detergent salt in particulate form and turbulently dispersing said salt for up to 3 seconds in an inert gaseous medium, initiating hydration of the dispersed salt particles by concurrently wetting them with an atomized stream of water or an aqueous solution of an alkali metal silicate metered to provide an amount of water sufficient to substantially hydrate the dispersed salt particles, said metered amount of water being at least a stoichiometric amount but not in excess of about 20% over said stoichiometric amount for hydration, and to cause agglomeration of the particles into agglomerates substantially all of which are small enough to pass through the sieve openings in a No. 8 U.S. Sieve Series, discharging said agglomerates into a closed container, maintaining the agglomerates therein to a temperature above 30.degree. C. and less than 100.degree. C. while continuously gently stirring the agglomerates to minimize formation of oversize lumps, maintaining the agglomerates in said container until their hydratable salt content has been substantially hydrated to a degree of hydration between 70% and 100% of theoretical, removing the hydrated agglomerates from said container and then drying the hydrated agglomerates while being gently stirred until their free moisture content is less than 5% by weight.

A continuous process for producing a dry-pourable, non-caking detergent composition which comprises turbulently dispersing for up to 3 seconds in an inert gaseous medium a particulate feed of at least one hydratable detergent salt, initiating hydration of the dispersed salt particles by impinging thereon an atomized stream of water metered to provide an amount of water sufficient to substantially hydrate said salt, said metered amount of water being at least a stoichiometric amount but not in excess of about 20% over said stoichiometric amount for hydration, and to cause the salt particles to agglomerate together into agglomerates substantially all of which are small enough to pass through the openings in a No. 8 U.S. Sieve Series, discharging said agglomerates into a closed container, heating the agglomerates therein to a temperature above 30.degree. C. and less than 100.degree. C. while continuously gently stirring the agglomerates to minimize formation of oversize lumps, maintaining the agglomerates in said container until they have been hydrated to at least about 70% of their hydration potential, removing the hydrated agglomerates from said container and turbulently dispersing them for up to 3 seconds in an inert gaseous medium while concurrently mixing therewith one or more members selected from the group consisting of non-ionic surfactants, anionic surfactants, cationic surfactants, neutral alkali metal salts, alkali metal hydroxides, solid chlorine releasing agents, alkali metal silicates and anti-soil redeposition agents, with the proviso that at least one member of the group upon being mixed with the hydrated salt agglomerates is in liquid form to provide sufficient wetting of the hydrated salt agglomerate surfaces for other particulate members of the group to adhere to the hydrated salt agglomerate surfaces and to each other to form new agglomerates containing as one component the hydrated salt agglomerates and as the other component one or more members selected from said group and then drying the new agglomerates under mild agitation conditions at temperatures up to about 60.degree. C. until their free moisture content is reduced to at least 5% by weight.