Stable, pourable alkali metal dithionite dispersion

Claim 2

A FLUENT HOMOGENEOUS, POURABLE, CHEMICALLY AND PHYSICALLY STABLE DISPERSION OF SOLID PARTILCS OF A WATER SOLUBLE DITHIONITE IN A LIQUID WHICH DOES NOT REACT THEREWITH OR CATALYZE THE DECOMPOSITION THEREOF, SAID LIQUID COMPRISING A MATERIAL WHICH SUPPRESSES THE DISSOLUTION OF THE PARTICLES IN THE LIQUID, THE MATERIAL BEING INERT WITH RESPECT TO THE DIHTHIONITE AND A NONSOLVENT THEREFOR, THE PH OF THE SYSTEM BEING AT LEAST 6.5 THE QUANTITY OF SAID MATERIAL BEING SUCH THAT THE PARTICLES ARE NOT DISSOLVED BY SAID LIQUID AN RETAIN THEIR PARTICULARE FORM, SAID SOLID PARTICLES CONSTITUTING BETWEEN ABOUT 20 PERCENT AND 45 PERCENT BY WEIGHT OF SAID DISPERSION, THE VISCOSITY OF SAID DISPERSION BEING BELOW ABOUT 50,000 CENTIPOISES.

Claim 3

The composition of claim 1 in which the liquid comprises water, the dithionite is of Zinc or an alkali metal in the solid hydrate form, and the suppressant comprises an organic compound.

Claim 4

The composition of claim 1 in which the liquid comprises water, the dithionite is of zincor an alkali metal in the solid hydrate form, and the suppressant comprises a water soluble salt of an acid, said salt being nonreactive with said dithionite hydrate.

Claim 5

The composition of claim 3 in which said salt is of a heavy metal, a periodic Group I or II metal, an amine, or ammonia and an inorganic acid.

Claim 6

The composition of claim 1 in which said liquid is water containing an organic liquid and an alkali metal or ammonium salt of an inorganic acid to suppress dissolution of the particles, the pH is alkaline, and the average maximum dinemsion of said particles is below about 320 microns.

Claim 7

The composition of claim 5 in which said dithionite is sodium dithionite dihydrate, said organic liquid comprises ethanol or methanol, said salt comprises sodium sulfate or sodium chloride, the viscosity is below about 15,000 centipoises, the maximum dimension of the particles is about 70 microns, and the average maximum dimension of the particles is below about 30 microns.

Claim 8

The composition of claim 6 in which a suspending agent is contained in aid liquid, and a buffer to maintain an alkaline pH is present.

Claim 9

In a method of storing and shipping zinc or alkali metal dithionite hydrate, the improvement of suspending finely divided particles thereof in a liquid which does not react therewith or catalyze the decomposition thereof, comprising a material which suppresses the dissolution of the particles in the liquid, the material being inert with respect to the dithionite and a nonsolvent therefor, and maintaining said particles in suspended form during storage and shipment thereof, the viscosity of the dispersion being below about 50,000 centipoises.

Claim 10

In a method of storing and shipping zinc or alkali metal dithionite hydrate, the improvement of suspending finely divided particles thereof in a liquid which does not react therewith or catalyze the decomposition thereof, comprising a material which suppresses the dissolution of the particles in the liquid, the material being inert with respect to the dithionite and a nonsolvent therefor, and maintaining said particles in suspended form during storage and shipment thereof, the viscosity of the dispersion being below about 50,000 centipoises.

Claim 11

The method of claim 8 in which said liquid is water containing an alkanol and an alkali metal or ammonium salt of an inorganic acid.

Claim 12

A fluent homogeneous, pourable, chemically and physically stable dispersion of solid particles of a water soluble dithionite in a suspending medium including a liquid which does not react therewith or catalyze the decomposition thereof, said liquid comprising a material which suppresses the dissolution of the particles in the liquid, the material being inert with respect to the dithionite and a nonsolvent therefor, the pH of the medium being alkaline, the quantity of said material bein such that the particles are not dissolved by said liquid and retain their particulate form, said solid particles constituting between about 20 and 45 percent by weight of said dispersion, in which said liquid is water, said material being an organic liquid and an alkali metal or ammonium salt of an inorganic acid, said dithionite is sodium dithionite dihydrate, said organic liquid comprises ethanol or methanol, said salt comprises sodium sulfate or sodium chloride, the viscosity of the dispersion is below about 15,000 centipoises, the maximum dimension of the particles is about 70 microns, the average maximum dimension of the particles is below about 30 microns, a suspending agent is contained in the liquid, a buffer to maintain an alkaline pH is present, and said suspending agent is a conventional suspending agent selected from the polysaccharides, chemically modified polysaccharides, water soluble polymers, and proteins of moderate molecular weight.

Claim 13

A fluent homogeneous, pourable, chemically and physically stable dispersion of solid particles of a water soluble dithionite in a suspending medium including a liquid which does not react therewith or catalyze the decomposition thereof, said liquid comprising a material which suppresses the dissolution of the particles in the liquid, the material being inert with respect to the dithionite and a nonsolvent therefor, the pH of the medium being alkaline, the quantity of said material bein such that the particles are not dissolved by said liquid and retain their particulate form, said solid particles constituting between about 20 and 45 percent by weight of said dispersion, in which said liquid is water, said material being an organic liquid and an alkali metal or ammonium salt of an inorganic acid, said dithionite is sodium dithionite dihydrate, said organic liquid comprises ethanol or methanol, said salt comprises sodium sulfate or sodium chloride, the viscosity of the dispersion is below about 15,000 centipoises, the maximum dimension of the particles is about 70 microns, the average maximum dimension of the particles is below about 30 microns, a suspending agent is contained in the liquid, a buffer to maintain an alkaline pH is present, and said suspending agent is a conventional suspending agent selected from the polysaccharides, chemically modified polysaccharides, water soluble polymers, and proteins of moderate molecular weight.

Claim 14

The composition of claim 10 in which suspending agent is a cellulose ether of polysaccharide gum selected from carboxymethyl cellulose, methylhydroxypropyl cellulose, ethylhydroxyethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxpropyl, cellulose, agar-agar, guar gum, mannogalactose, sodium alginate, gum tragacanth, starch, and hydroxyalkylated starch.

Claim 15

The composition of claim 11 in which the suspending agent is guar gum.