A novel process for treating pickling acid residue and recovering sulfates and nickel therefrom has been developed. By lowering the pH of a magnesium compound slurry to 4-5.5 with sulfuric acid containing pickling acid residue in the presence of ammonium sulfate, both magnesium sulfate and nickel sulfate are solubilized. Magnesium sulfate and nickel sulfate solution is separated from the solids by filtration and an iron hydroxide and chromium hydroxide residue is obtained as a precipitate. Magnesium sulfate and nickel sulfate are then separated from the solution.

A method for producing a double sulfate of potassium and magnesium by dry mechanical attrition of potassium sulfate and magnesium sulfate hexahydrate, comprising obtaining potassium sulfate by sulfatation of potash to bisulfate of potassium and disproportionation of the bisulfate of potassium to potassium sulfate in a water-methanol solution, and obtaining magnesium sulfate hexahydrate by sonic-assisted partial sulfatation of calcined serpentinic silicate.

A method for producing a double sulfate of potassium and magnesium by dry mechanical attrition of potassium sulfate and magnesium sulfate hexahydrate, comprising obtaining potassium sulfate by sulfatation of potash to bisulfate of potassium and disproportionation of the bisulfate of potassium to potassium sulfate in a water-methanol solution, and obtaining magnesium sulfate hexahydrate by sonic-assisted partial sulfatation of calcined serpentinic silicate.

A method for processing a metallurgical waste acid, includes the following steps. First, a certain amount of a metallurgical waste acid is added into a reaction kettle. Then, the metallurgical waste acid and magnesium slag are added into the reaction kettle in a weight ratio ranging from 5:1 to 15:1 and are stirred into a mixed waste water. The reaction temperature is the room temperature. Then, a certain amount of sulfuric acid is added into the reaction kettle to control the mixed waste water within a pH range. At last, the mixed waste water is filtered.

A method for processing a metallurgical waste acid, includes the following steps. First, a certain amount of a metallurgical waste acid is added into a reaction kettle. Then, the metallurgical waste acid and magnesium slag are added into the reaction kettle in a weight ratio ranging from 5:1 to 15:1 and are stirred into a mixed waste water. The reaction temperature is the room temperature. Then, a certain amount of sulfuric acid is added into the reaction kettle to control the mixed waste water within a pH range. At last, the mixed waste water is filtered.

A forest fire retardant composition contains a retardant compound that includes a phosphate salt. The phosphate salt may include diammonium phosphate, diammonium orthophosphate, monoammonium phosphate, monoammonium orthophosphate, monosodium phosphate, disodium phosphate, disodium phosphate hydrate, sodium ammonium phosphate, sodium ammonium phosphate hydrate, sodium tripolyphosphate, trisodium phosphate, or dipotassium phosphate, and combinations thereof. The forest fire retardant composition may include an ammonium source. The composition may be in the form of a dry concentrate, a liquid concentrate, or a final diluted product. The final diluted product is effective in suppressing, retarding, and controlling forest fires while exhibiting corrosion resistance and low toxicity.

A forest fire retardant composition contains a retardant compound that includes a phosphate salt. The phosphate salt may include diammonium phosphate, diammonium orthophosphate, monoammonium phosphate, monoammonium orthophosphate, monosodium phosphate, disodium phosphate, disodium phosphate hydrate, sodium ammonium phosphate, sodium ammonium phosphate hydrate, sodium tripolyphosphate, trisodium phosphate, or dipotassium phosphate, and combinations thereof. The forest fire retardant composition may include an ammonium source. The composition may be in the form of a dry concentrate, a liquid concentrate, or a final diluted product. The final diluted product is effective in suppressing, retarding, and controlling forest fires while exhibiting corrosion resistance and low toxicity.

A forest fire retardant composition contains a retardant compound that includes a phosphate salt. The phosphate salt may include diammonium phosphate, diammonium orthophosphate, monoammonium phosphate, monoammonium orthophosphate, monosodium phosphate, disodium phosphate, disodium phosphate hydrate, sodium ammonium phosphate, sodium ammonium phosphate hydrate, sodium tripolyphosphate, trisodium phosphate, or dipotassium phosphate, and combinations thereof. The forest fire retardant composition may include an ammonium source. The composition may be in the form of a dry concentrate, a liquid concentrate, or a final diluted product. The final diluted product is effective in suppressing, retarding, and controlling forest fires while exhibiting corrosion resistance and low toxicity.

A forest fire retardant composition contains a retardant compound that includes a phosphate salt. The phosphate salt may include diammonium phosphate, diammonium orthophosphate, monoammonium phosphate, monoammonium orthophosphate, monosodium phosphate, disodium phosphate, disodium phosphate hydrate, sodium ammonium phosphate, sodium ammonium phosphate hydrate, sodium tripolyphosphate, trisodium phosphate, or dipotassium phosphate, and combinations thereof. The forest fire retardant composition may include an ammonium source. The composition may be in the form of a dry concentrate, a liquid concentrate, or a final diluted product. The final diluted product is effective in suppressing, retarding, and controlling forest fires while exhibiting corrosion resistance and low toxicity.

Magnesium sulfate granulates contain at least 90 wt. % synthetic magnesium sulphate hydrate with respect to the total mass of the magnesium sulphate granulate, and have a dry loss of less than 2 wt. % determined by drying of the granulate for 2 hours at 105 C. and 1 bar. Further, a method is used for producing said magnesium sulfate granulates and to their use in urea-containing fertilizer compositions.