Process for producing potassium chloride granulates
AssigneeK+S Aktiengesellschaft
InventorsGuido Baucke, Armin Dietrich, Stefan Dressel, Sebastian Kopf, Paul Meissner, Wolfgang Walczyk, Ludger Waldmann
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Abstract
A method for producing potassium chloride granulates from a crystalline potassium chloride raw material. The potassium chloride raw material is treated, prior to granulation, with at least one alkali metal carbonate and at least one phosphate additive selected from alkali metal monophosphates, alkali metal pyrophosphates, linear alkali metal polyphosphates and mixtures thereof, in the presence of water.
Claims20
A process for producing potassium chloride granules from a crystalline potassium chloride raw material, the process comprising:
- treating the crystalline potassium chloride raw material, prior to the granulating, with at least one alkali metal carbonate in an amount of from 0.05 to 0.7 wt. % and at least one phosphate additive selected from the group consisting of an alkali metal monophosphate, an alkali metal pyrophosphate, and a linear alkali metal polyphosphate, in an amount of from 0.025 to 0.4 wt. %, in the presence of water, the weight percentages based on solid constituents of the crystalline potassium chloride raw material, to obtain a treated potassium chloride material;
- and
- subsequently subjecting the treated potassium chloride material to granulation, the granulation comprising compression agglomeration,
- wherein a counterion of the at least one phosphate additive is at least one selected from the group consisting of sodium and potassium,
- wherein the at least one alkali metal carbonate is at least one selected from the group consisting of a sodium carbonate, potassium carbonate and a mixture thereof, and
- wherein at least 90 wt. % of the potassium chloride granules have a particle size or particle diameter in a range of from 0.5 to 8 mm.
A method for reducing moisture absorption and/or increasing fracture resistance or cracking resistance of potassium chloride granules exposed to high air humidity, the method comprising:
- bringing a combination of at least one alkali metal carbonate in an amount of from 0.05 to 0.7 wt. %, at least one phosphate additive in an amount of from 0.025 to 0.4 wt. %, and water into contact with a crystalline potassium chloride raw material, the weight percentages based on solid constituents of the crystalline potassium chloride raw material, to obtain a treated potassium chloride material;
- and
- subsequently, granulating the treated potassium chloride material, to form the potassium chloride granules, the granulating comprising compression agglomeration,
- wherein a counterion of the at least one phosphate additive is at least one selected from sodium and potassium,
- wherein the at least one alkali metal carbonate is at least one selected from the group consisting of a sodium carbonate, a potassium carbonate, and a mixture thereof, and
- wherein the potassium chloride granules, when having a grain size in a range of from 2.5 to 3.15 mm have a reduced moisture absorption, based on mass measurement after 24 hours at 20° C. under relative humidity in a range of from 70 to 73%, and/or an increased fracture resistance or cracking resistance, based on mean cracking resistance measured with an ERWEKA® TBH 425D tablet hardness tester on 56 individual agglomerates of different particle size in a 2.5 to 3.15 mm fraction, relative to otherwise identically made potassium chloride granules, using only one of the alkali metal carbonate and the phosphate additive in an identical mass to a total mass of the alkali metal carbonate and the phosphate additive.
Dependencies are inferred from the claim text.