Process for the treatment of saline water
First Claim
1. A process for treatment of water containing dissolved solids, said process being usable for each of the following types of water:
- Type 1 water comprising total dissolved solids of 1 to 60 g/L, a Cl−
/HCO3−
ratio of <
2 and a Cl−
/2SO42−
ratio of >
1,Type 2 water comprising total dissolved solids of 1 to 15 g/L, a Cl−
/HCO3−
ratio of ≧
2 and a Cl−
/2SO42−
ratio of >
1,Type 3 water comprising total dissolved solids of 1 to 15 g/L, a Cl−
/HCO3−
ratio of >
2 and a Cl−
/2SO42−
ratio of <
1,Type 4 water comprising total dissolved solids of >
15 and ≦
60 g/L, a Cl−
/HCO3−
ratio of >
5 and a Cl−
/2SO42−
ratio of >
7,Type 5 water comprising total dissolved solids of >
15 and ≦
60 g/L, a Cl−
/HCO3−
ratio of >
5 and a Cl−
/2SO42−
ratio of <
7,Type 6 water comprising total dissolved solids of >
60 g/L, a Cl−
/HCO3−
ratio of >
5 and a Cl−
/2SO42−
ratio of >
9, andType 7 water comprising total dissolved solids of >
60 g/L, a Cl−
/HCO3−
ratio of >
5 and a Cl−
/2SO42−
ratio of <
9,said process comprising the steps of;
(a) contacting the said water with a first reagent comprising a source of calcium ions selected from the group consisting of calcium oxide, calcium hydroxide, and a combination thereof as a sole agent to cause at least some solids dissolved in the water to react with the first reagent and to form a first solid product and a partially processed water, wherein the water containing dissolved solids is a Type 1 water and the first solid product is precipitated calcium carbonate (PCC) or the water containing dissolved solids is a water of any of Types 2 to 7 and the first solid product is gypsum-magnesium hydroxide mixture (GMH) and wherein the said GMH is further treated by the addition of sulphuric acid to react with 5-50% of the stoichiometric amount of magnesium hydroxide present in the GMH;
(b) recovering the first solid product from the partially processed water;
(c) at least partially concentrating the partially processed water or a portion thereof, so as to promote the formation of a precipitate and a mother liquor; and
(d) recovering the precipitate from the mother liquor as a second product, wherein the water is a water of type 1 and the second product is sodium hydroxide, sodium sulphate, sodium chloride or sodium carbonate;
wherein the water is a water of any one of types 2, 4, 5, 6 and 7, and the second product is sodium chloride;
or wherein the water is a water of type 3, and the second product is sodium sulphate.
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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.
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Citations
22 Claims
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1. A process for treatment of water containing dissolved solids, said process being usable for each of the following types of water:
-
Type 1 water comprising total dissolved solids of 1 to 60 g/L, a Cl−
/HCO3−
ratio of <
2 and a Cl−
/2SO42−
ratio of >
1,Type 2 water comprising total dissolved solids of 1 to 15 g/L, a Cl−
/HCO3−
ratio of ≧
2 and a Cl−
/2SO42−
ratio of >
1,Type 3 water comprising total dissolved solids of 1 to 15 g/L, a Cl−
/HCO3−
ratio of >
2 and a Cl−
/2SO42−
ratio of <
1,Type 4 water comprising total dissolved solids of >
15 and ≦
60 g/L, a Cl−
/HCO3−
ratio of >
5 and a Cl−
/2SO42−
ratio of >
7,Type 5 water comprising total dissolved solids of >
15 and ≦
60 g/L, a Cl−
/HCO3−
ratio of >
5 and a Cl−
/2SO42−
ratio of <
7,Type 6 water comprising total dissolved solids of >
60 g/L, a Cl−
/HCO3−
ratio of >
5 and a Cl−
/2SO42−
ratio of >
9, andType 7 water comprising total dissolved solids of >
60 g/L, a Cl−
/HCO3−
ratio of >
5 and a Cl−
/2SO42−
ratio of <
9,said process comprising the steps of; (a) contacting the said water with a first reagent comprising a source of calcium ions selected from the group consisting of calcium oxide, calcium hydroxide, and a combination thereof as a sole agent to cause at least some solids dissolved in the water to react with the first reagent and to form a first solid product and a partially processed water, wherein the water containing dissolved solids is a Type 1 water and the first solid product is precipitated calcium carbonate (PCC) or the water containing dissolved solids is a water of any of Types 2 to 7 and the first solid product is gypsum-magnesium hydroxide mixture (GMH) and wherein the said GMH is further treated by the addition of sulphuric acid to react with 5-50% of the stoichiometric amount of magnesium hydroxide present in the GMH; (b) recovering the first solid product from the partially processed water; (c) at least partially concentrating the partially processed water or a portion thereof, so as to promote the formation of a precipitate and a mother liquor; and (d) recovering the precipitate from the mother liquor as a second product, wherein the water is a water of type 1 and the second product is sodium hydroxide, sodium sulphate, sodium chloride or sodium carbonate;
wherein the water is a water of any one of types 2, 4, 5, 6 and 7, and the second product is sodium chloride;
or wherein the water is a water of type 3, and the second product is sodium sulphate.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification