Process and apparatus for the treatment of saline water
First Claim
1. A method of treatment of water containing dissolved solids, wherein the water is selected from the group consisting of types 1 to 7 waters as defined in Table 1:
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Accused Products
Abstract
A process and an apparatus are described for treating seven types of saline waters each having a concentration of total dissolved solids exceeding 1 g/L, wherein the concentration of total dissolved solids, the ratio of the chloride ion concentration to the bicarbonate ion concentration and the ratio of the chloride ion concentration to the sulphate ion concentration of each of the water types are as indicated in Table 1. The process includes the steps of contacting the water with a first reagent comprising a source of calcium ions selected from calcium oxide and calcium hydroxide to form a first solid product which is recovered. The process includes a further step of subjecting at least a portion of the partially processed water to at least partial evaporation so as to promote the formation of a precipitate and a mother liquor. The precipitate is recovered as a second product.
82 Citations
36 Claims
- 1. A method of treatment of water containing dissolved solids, wherein the water is selected from the group consisting of types 1 to 7 waters as defined in Table 1:
- 27. An apparatus for the treatment of water containing dissolved solids, wherein the water is selected from the group consisting of types 1 to 7 waters, as defined in Table 1:
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35. A process for treating a saline process water in a gold mining operation comprising the steps of adding a lime slurry [Ca(OH)2] first under fast and then under slow mixing conditions to form a slurry, which slurry is then washed and dewatered to produce a compound of desired thickness, comprised of Mg(OH)2 and CaCO3 minerals, and storing and aging the spent water to mature by aeration, which solution can then be fed directly to a CIL circuit.
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36. A process for the manufacture of PCC compounds from mildly saline waters of surface or ground water origin, comprising:
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(a) if required, pre-concentration of the raw ground water solution by natural evaporation or artificial means, to adjust bicarbonate (HCO3) ion concentration in the solution to between 1 g/L and 15 g/L HCO3;
(b) reaction of the said raw ground water or pretreated feed solution with hydrated lime slurry, under constant stirring conditions, at temperatures 30°
C. or higher, to allow formation of a slurry due to nucleation of fine grain calcium carbonate crystals;
(c) transfer of the slurry to a solids/liquid separation vessel to allow proportional removal of the decarbonated supernatant (spent water) to a neutralisation vessel, followed by pH adjustment to around pH 7 by adding acid, and re-use or disposal of the resultant neutralised water;
(d) transfer of the slurry to a wash thickener vessel, washing the slurry first with fresh water to remove excess dissolved salts, followed by thickening to obtain a precipitated calcium carbonate slurry product;
(e) optionally and depending on market requirements, further dewatering of the precipitated calcium carbonate slurry product (in “
d”
) to obtain a cake, which is dried and powdered to obtain a precipitated calcium carbonate powder product.
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Specification