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US 7,115,201 B2Granted
Method of treating mine drainage
AssigneeKroff Chemical Company
InventorPaul Rey
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Abstract
A method of treating mine drainage water including the step of adding a scale control agent to the mine drainage water and, optionally, adding an oxidizing agent to the mine drainage water and/or precipitating and settling the metals in their hydroxide form from the water. The treated water may be safely returned to the environment.
Claims25
A method for inhibiting precipitation of calcium salt and metal oxide and/or metal hydroxide from hard mine drainage water comprising:
- (a) providing hard mine drainage water having a pH of from 4.5 to 10;
- calcium hardness greater than 100 mg/l of Ca+2 as calcium carbonate;
- alkalinity greater than 100 mg/l as calcium carbonate;
- and one or more metal ions or metal salts selected from the group consisting of iron, copper, zinc, lead, mercury, cadmium, arsenic, barium, selenium, silver, chromium, aluminum, manganese, nickel, cobalt, uranium, and antimony;
- and
- (b) adding a scale control agent to the mine drainage water, wherein the scale control agent is one or more selected from the group consisting of polymeric scale control agents, water-soluble polycarboxylates, phosphonates, organic phosphates, organic polyphosphates, and sulfonates, at a level sufficient to inhibit precipitation of calcium salt and metal oxide and/or metal hydroxide in said hard mine drainage water.
3 more elements
Dependencies are inferred from the claim text.