Method for producing potassium chloride granular materials
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 granular materials from a crystalline potassium chloride raw material, wherein, before the granulation process, the potassium chloride raw material is treated with at least one alkali metal carbonate and at least one metaphosphate additive in the presence of water.
Claims19
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 granulating, with at least one alkali metal carbonate in an amount of from 0.05 to 0.7 wt. % and at least one alkali metal metaphosphate 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, granulating the treated potassium chloride material, the granulating comprising compression agglomeration of the treated potassium chloride material,
- wherein the at least one alkali metal carbonate is selected from the group consisting of a potassium carbonate, a sodium carbonate, and a mixture thereof,
- wherein a counterion of the at least one alkali metal metaphosphate is at least one selected from the group consisting of sodium and potassium, 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 alkali metal metaphosphate 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 obtain the potassium chloride granules,
- 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 71%, 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 metaphosphate in an identical mass to a total mass of the alkali metal carbonate and the metaphosphate,
- wherein the at least one alkali metal carbonate is selected from the group consisting of a potassium carbonate, a sodium carbonate, and a mixture thereof,
- wherein a counterion of the at least one alkali metal metaphosphate is at least one selected from the group consisting of sodium and potassium,
- wherein the granulating comprises compression agglomeration of the treated potassium chloride material.
Dependencies are inferred from the claim text.