Cyclic treatment process for wastewater containing cobalt-nickel heavy metal ions

Abstract

The invention provides a cyclic treatment process for wastewater containing cobalt-nickel heavy metal ions, belonging to the field of treatment of heavy metal wastewater. The cyclic treatment processcomprises the following steps: heavy metal recovery; solid-liquid separation; primary filtration; removal of SO4<2->; first-stage cyclone separation; gypsum drying; re-precipitation; stripping; ternary precipitation; re-filtration; and neutralization. According to the invention, ammonia water is used in the replacement of NaOH, so the production cost of enterprises and the salt content of discharged water are reduced; the heavy metals cobalt and nickel are reused; ammonia is recycled; profits are produced as gypsum is sold; and up-to-standard discharge of the wastewater is realized. Since a precision filtration process and other processes are additionally carried out and processes like multiple precipitation and multiple filtration are carried out for deep recovery of heavy metals such ascobalt, nickel and manganese, the discharged wastewater has lower salt content and lower concentration of heavy metal ions, and the recycling of heavy metal ions and the harmless discharge of the wastewater are realized. After treatment of the wastewater with the cyclic treatment process, the concentrations of NH<4+>, Co<2+>, Ni<2+> and SO4<2-> in the wastewater are lower than 27.32 g / L, 55.49 mg / L, 60-65 mg / L and 103.62 g / L, respectively and are reduced to 15 mg / L, 1 mg / L, 1 mg / L and almost zero.

Description

technical field [0001] The invention relates to the field of heavy metal wastewater treatment, in particular to a method for treating wastewater containing heavy metal ions such as cobalt and nickel. Background technique [0002] In the recycling process of regenerated cobalt and nickel resources, the leaching solution of cobalt and nickel waste is extracted and divided into two parts: the extraction product and the raffinate. The extracted product enters the next process to synthesize the product, and the raffinate becomes waste water. Further recovery, purification, discharge after reaching the discharge standard. In the extraction process of the sulfuric acid system, at this time, the raffinate mainly contains Co 2+ 、Ni 2+ , SO4 2- . The traditional extraction process uses NaOH and extractant for saponification reaction. The amount of NaOH used is large, and the effluent from the extraction process has a high salt content, which will increase the downstream water trea...

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Problems solved by technology

[0004] In order to overcome the problems existing in the prior art, the present invention provides a recycling process for waste water containing cobalt and nickel heavy metal ions, which solves the problem of high cost of NaOH by using ammonia instead of sodium, and optimizes the waste water treatment process for deep recovery. While removing heavy metals such as cobalt and nickel, recycling ammonia, SO 4 2- Become a gypsum product, so that the discharged wastewater has a lower salt content and a lower concentration of heavy metal ions, and also increases corporate profits

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