Process for purifying potassium chloride
AssigneeKlinge Chemicals Ltd.
InventorsSteve Lockie, Douglas H. Brown
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Abstract
A process for the preparation of purified potassium chloride comprises the at least partial removal of one or more class 1 heavy metal impurity (lead, arsenic, cadmium and/or mercury) from potassium chloride process liquor by an ion exchange step. The process uses an ion exchange resin and achieves high levels of purity and is compatible with high flow rates. A recrystallisation step (e.g. a cooling crystallization step) may be employed subsequent to the ion exchange step.
Claims16
A process for the preparation of purified potassium chloride comprising the step of at least partially removing one or more class 1 heavy metal impurities selected from the group consisting of lead impurities, arsenic impurities, cadmium impurities and mercury impurities, from potassium chloride process liquor by ion exchange, and the process comprising a recrystallisation step subsequent to the ion exchange, wherein said recrystallisation step is cooling crystallisation.
A process for the preparation of purified potassium chloride comprising the step of at least partially removing one or more class 1 heavy metal impurities selected from the group consisting of lead impurities, arsenic impurities, cadmium impurities and mercury impurities, from potassium chloride process liquor by ion exchange, and after the ion exchange, the process comprising a filtration step prior to a recrystallisation step.
A process for the preparation of purified potassium chloride comprising the step of at least partially removing one or more class 1 heavy metal impurities selected from the group consisting of lead impurities, arsenic impurities, cadmium impurities and mercury impurities, from potassium chloride process liquor by ion exchange, and subsequent to the ion exchange, the process comprising a recrystallisation step, wherein after the recrystallisation step, the process comprises centrifuging to displace the process liquor from potassium chloride solid, spraying water onto the solid to tune its purity and to remove the process liquor, and adding more raw material to the process liquor.
A process for the preparation of purified potassium chloride comprising the step of at least partially removing one or more class 1 heavy metal impurities selected from the group consisting of lead impurities, arsenic impurities, cadmium impurities and mercury impurities, from potassium chloride process liquor by ion exchange, wherein the ion exchange comprises passing the process liquor through a first ion exchange vessel and then a second ion exchange vessel, both vessels containing ion exchange resin, and wherein the process further comprises regenerating the ion exchange resin in the first ion exchange vessel more frequently than regenerating the ion exchange resin in the second ion exchange vessel.
Dependencies are inferred from the claim text.