Water treatment
AssigneeCsir
InventorsJohannes Philippus Maree, Guido Kamiel Erik Bieseman
Life of this patent
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Abstract
A method of treating water to remove fluoride ions from the water, thereby to reduce the dissolved fluoride content of the water, is provided. The method includes, in a contacting step, contacting water containing dissolved fluoride ions with alumina, to cause the fluoride ions to react with and become bound to the alumina. In a regenerating step, the alumina, when spent, is regenerated to drive off fluoride ions bound thereto. The regenerated alumina is recycled to the contacting step where it is used to remove further fluoride ions from the water. The fluoride ions driven off the alumina in the regenerating step are passed on to downstream processing thereof.
Claims16
A method of treating water to remove fluoride ions from the water, thereby to reduce the dissolved fluoride content of the water, the method including:
- in a contacting step, contacting water containing dissolved fluoride ions with bauxite, to cause the fluoride ions to react with bauxite;
- in a drying step, heating the bauxite, when spent, to a temperature in the range 100° C. to 250° C. to dry the bauxite and to drive off fluoride ions bound thereto as HF gas/vapour;
- recycling the dried bauxite to the contacting step where it is used to remove further fluoride ions from the water or passing the dried bauxite on for downstream use as smelter feed;
- and
- passing on the HF gas/vapour produced in the drying step, to downstream processing thereof.
A method of treating water to remove fluoride ions from the water, thereby to reduce the dissolved fluoride content of the water, the method including:
- in a contacting step, contacting water containing dissolved fluoride ions with alumina, by passing the water through a bed of the alumina which is thus in particulate form, with the fluoride ions reacting with the alumina to produce aluminium fluoride in accordance with Reaction (1):
- AI2O3+3H2O+6F−→2AIF3+6OH− (1)
- in a regenerating step, regenerating the alumina, when spent, by heating the spent alumina to drive off fluoride ions as HF gas/vapour, in accordance with Reaction (2):
- 2AIF3+3H2O→AI2O3+6HF (2);
- recycling the regenerated alumina to the contacting step where it is used to remove further fluoride ions from the water;
- and
- passing on the HF gas/vapour driven off during the regenerating step, to downstream processing thereof.
Dependencies are inferred from the claim text.