Method for recycling acid and heavy metal in gold smelting acid wastewater

Abstract

The invention provides a method for recycling acid and heavy metal in gold smelting acid wastewater. The method comprises the steps of: adsorbing sulfuric acid in the acid wastewater by utilizing acid adsorption resins; adding oxidizing agents for oxidizing divalent iron in the wastewater into ferric ion; adding ferrite yellow seed crystals and rising the temperature for reacting; regulating a pH value to be 1.5-4.5; separating out the iron in the waste acid in a ferrite yellow form; adding zinc powder and replacing copper in the wastewater; regulating a pH value of the water subjected to copper separation to be 6.5-8.0; precipitating out zinc hydroxide; removing the wastewater of zinc and performing reverse osmosis membrane treatment; recycling the fresh water used in reverse osmosis in the production process; performing high pressure membrane treatment on dense water for reverse osmosis; evaporating the dense water subjected to the high pressure membrane treatment to obtain salt contents of sodium sulfate; performing reverse osmosis re-treatment on the fresh water subjected to high pressure membrane treatment; regenerating by using deionized water after the saturation of acid adsorption of the acid adsorption resins to obtain 15-20 percent of sulfuric acid.

Description

technical field [0001] The invention belongs to the field of gold smelting industrial wastewater treatment, and relates to a recovery process and method for acidic wastewater containing heavy metals such as sulfuric acid and zinc and copper, in particular to a method for recovering acid and metallic zinc and copper from acidic wastewater. Background technique [0002] In the process of producing sulfuric acid and extracting copper sulfate from gold smelting flue gas, a large amount of pickling wastewater is produced, and its composition is roughly 5%-8% of sulfuric acid, 1%-2% of zinc, 0.1% of iron, 0.03% of copper, and 1% of sodium -2%, magnesium 0.02%, calcium 0.01%, the previous treatment method is to add calcium oxide to neutralize the precipitation, the process produces a lot of waste residue, these waste residues are generally used to produce gypsum, but because it contains a lot of heavy metals, the quality of gypsum products is poor , the production process is compli...

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Problems solved by technology

[0002] In the process of producing sulfuric acid and extracting copper sulfate from gold smelting flue gas, a large amount of pickling wastewater is produced, and its composition is roughly 5%-8% of sulfuric acid, 1%-2% of zinc, 0.1% of iron, 0.03% of copper, and 1% of sodium -2%, magnesium 0.02%, calcium 0.01%, the previous treatment method is to add calcium oxide to neutralize the precipitation, the process produces a lot of waste residue, these waste residues are generally used to produce gypsum, but because it contains a lot of heavy metals, the quality of gypsum products is poor , the production process is complicated, the cost is high, the price is low, and there is no economic benefit

This conventional process cannot recover the acid in the pickling wastewater, and needs to use a large amount of calcium oxide to neutralize it, the cost is high, a large amount of solid waste is generated, and the heavy metals in the wastewater cannot be recovered, so it is urgently needed to improve

CN103693727A discloses a process of calcining waste residue, which can produce sulfuric acid, but the calcination process consumes a lot of energy and the benefits are not obvious. Therefore, the present invention proposes a new process for recovering acid and heavy metals

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