Granular calcium hypochlorite coated with a low melting inorganic salt by spray graining

Claim 1

A method for preparing coated particulate solid calcium hypochlorite from a pumpable and sprayable molten hydrated low melting inorganic salt which comprises: a. maintaining a moving bed of particulate solid calcium hypochlorite core particles containing from about 50 to about 85 percent available chlorine on a dry basis and from about 0.5 to about 30 percent by weight of water in the lower part of a distributing zone having an upper part and a lower part, b. maintaining a temperature in said distribution zone in the range from about 0 to about 40° C., c. lifting a portion of said moving bed to said upper part and releasing said particles to separately fall through said distributing zone to said bed d. spraying on said falling particles a melt of hydrated low melting inorganic salt, e. wherein said low melting inorganic salt is selected from the group consisting of hydrated alkali metal metaborate, hydrated alkali metal tetraborate, hydrated aluminum sulfate, hydrated magnesium sulfate, eutectic mixtures of alkali metal metaborate and hydrated alkali metal tetraborate, and mixtures thereof, f. simultaneously cooling and solidifying said melt on the surface of said falling particles whereby said particles are coated with at least one outer layer of said low melting inorganic salt, g. removing at least a portion of the resulting coated rounded solid calcium hypochlorite particles from said distributing zone, h. wherein said exterior coating ranges from about 4 to about 45 percent by weight of said particles, and i. wherein said calcium hypochlorite core particles are prepared by spray graining of a calcium hypochlorite slurry in a distribution zone prior to coating with said hydrated low melting inorganic salt.

Claim 2

A method for preparing coated particulate solid calcium hypochlorite from a pumpable and sprayable molten hydrated low melting inorganic salt which comprises: a. maintaining a moving bed of particulate solid calcium hypochlorite core particles containing from about 50 to about 85 percent available chlorine on a dry basis and from about 0.5 to about 30 percent by weight of water in the lower part of a distributing zone having an upper part and a lower part, b. maintaining a temperature in said distribution zone in the range from about 0 to about 40° C., c. lifting a portion of said moving bed to said upper part and releasing said particles to separately fall through said distributing zone to said bed d. spraying on said falling particles a melt of hydrated low melting inorganic salt, e. wherein said low melting inorganic salt is selected from the group consisting of hydrated alkali metal metaborate, hydrated alkali metal tetraborate, hydrated aluminum sulfate, hydrated magnesium sulfate, eutectic mixtures of alkali metal metaborate and hydrated alkali metal tetraborate, and mixtures thereof, f. simultaneously cooling and solidifying said melt on the surface of said falling particles whereby said particles are coated with at least one outer layer of said low melting inorganic salt, g. removing at least a portion of the resulting coated rounded solid calcium hypochlorite particles from said distributing zone, h. wherein said exterior coating ranges from about 4 to about 45 percent by weight of said particles, and i. wherein said calcium hypochlorite core particles are prepared by spray graining of a calcium hypochlorite slurry in a distribution zone prior to coating with said hydrated low melting inorganic salt.