METHOD OF PREPARING A WATER-REACTIVE SULFIDE MATERIAL
A process for producing a low-cost water-reactive metal sulfide material includes dissolving a substantially anhydrous alkali metal salt and a substantially anhydrous sulfide compound in a substantially anhydrous polar solvent, providing differential solubility for a substantially high solubility alkali metal sulfide and a substantially low solubility by-product, and forming a mixture of the high solubility alkali metal sulfide and the low solubility by-product; separating the low solubility by-product from the mixture to isolate the supernatant including the alkali metal sulfide, and separating the polar solvent from the alkali metal sulfide to produce the alkali metal sulfide. The present invention provides a scalable process for production of a high purity alkali metal sulfide that is essentially free of undesired by-products.
1 - 34 . (canceled)
35 . A method for producing an alkali metal sulfide composite comprising:
reacting at least one substantially anhydrous alkali metal salt with at least one substantially anhydrous sulfide compound in one or more substantially anhydrous polar solvents;
forming a mixture comprising at least one alkali metal sulfide, and at least one by-product;
separating the at least one by-product from the at least one alkali metal sulfide; and
evaporating the polar solvent.
36 . The method of claim 35 , wherein one of the substantially anhydrous sulfide compounds is a polysulfide comprises Na 2 S x , where x is greater than 1 but less than or equal to 10.
37 . The method of claim 35 , wherein the at least one substantially anhydrous sulfide compound comprises Na 2 S, K 2 S, or (NH 4 ) 2 S.
38 . The method of claim 35 , wherein the at least one substantially anhydrous alkali metal salt is present in the reacting step in a stoichiometric excess.
39 . The method of claim 35 , wherein the at least one substantially anhydrous alkali metal salt is present in the reacting step in an amount of 150% of stoichiometric.
40 . The method of claim 35 , wherein separating the at least one by-product from the at least one alkali metal sulfide further comprises at least one of centrifuging, filtering, gravity settling, and cooling.
41 . The method of claim 35 , wherein the at least one substantially anhydrous alkali metal salt comprises LiF, LiCl, LiBr, or LiI.
42 . The method of claim 35 , further comprising drying the alkali metal sulfide composite.
43 . The method of claim 35 , wherein separating the polar solvent from the supernatant further comprises at least one of evaporating the polar solvent, recrystallization, and heating under vacuum.
44 . The method of claim 35 , wherein the substantially anhydrous polar solvent comprises at least one alcohol selected from the group consisting of ethanol, 1-propanol, 1-butanol, ethanol denaturing agents, and mixtures thereof.
45 . The method of claim 35 , wherein the alkali metal sulfide composite comprises Li 2 S.
46 . The method of claim 45 , wherein the alkali metal sulfide composite comprises the at least one substantially anhydrous alkali metal salt.
47 . The method of claim 35 , wherein the alkali metal sulfide composite further comprises a Li 3 OCl phase.
48 . The method of claim 35 , wherein the alkali metal sulfide composite further comprises LiCl, Li 2 O, Li 2 CO 3 , or LiOH.
49 . The method of claim 36 , wherein the alkali metal sulfide composite further comprises NaX or KX where X is one or more of a halogen comprising F, Cl, Br, or I.
50 . The method of claim 49 , wherein the NaX or KX is present at an amount equal to or less than 3% by weight of the alkali metal sulfide composite.
51 . The method of claim 35 , wherein the dissolving further comprises the addition of elemental sulfur to the one or more substantially anhydrous polar solvents.
52 . The method of claim 35 , wherein the at least one alkali metal salt has a water content of 0% to 5% by weight.
53 . The method of claim 35 , wherein the at least one sulfide compound has a water content of 0% to 5% by weight.
54 . The method of claim 35 , wherein the polar organic solvent has a water content of 0% to 5% by weight.