Recovery process of rare noble metal in waste water and nano iron reaction device used therein

Abstract

The invention discloses a recovery process of rare noble metal in waste water and a nano iron reaction device used therein. The recovery process comprises the following steps: entering heavy metal waste water into an adjusting pool and then entering into the nano iron reaction device after improvement, adding nano iron in an amount which is 2 to 3 times that of the total content of heavy metal ions of the waste water, and completely stirring and reacting for 20 to 40 min; controlling the adding amount of the nano iron and the reaction time through on-line oxidation-reduction potential (ORP) evaluation; after reaction, entering the output water into a coagulation and precipitation integrated pool to precipitate and separate; entering the output water after precipitate into a water outlet pool through a filter; discharging sludge to a sludge pool; and after improvement, entering a concentration tank, performing further concentration, dehydrating by using a filter press and recycling. A water inlet of the nano iron reaction device is formed in the upper part of a reaction area and is led to a position near a medicating port at the lower part of the reaction area through a downward straight pipe; a vertical partition board is arranged at the connection position of the reaction area and a precipitation area. The recovery process can realize recovery of rare noble metals such as gold, silver, selenium and copper. The nano iron reaction device is improved, so that the waste water and the nano iron can be completely contacted to react and can be separated well.

Description

technical field [0001] The invention belongs to the technical field of industrial waste water treatment, and relates to a recovery process of rare and precious metals in waste water and a nano-iron reaction device used therein. Background technique [0002] Wastewater produced in the smelting and electroplating industries contains a large amount of heavy metals, many of which contain rare and precious metals such as gold, silver, selenium and copper. Heavy metal pollution is a carcinogenic, teratogenic, and mutagenic hazard to humans. Traditional methods can only remove heavy metals in wastewater, but cannot recycle valuable metals, resulting in waste of resources and secondary pollution. [0003] Generally, heavy metal wastewater has complex components, contains a variety of heavy metal ions, high acid content, high salt content, and a wide range of water quality fluctuations, making treatment difficult and costly. At present, most of the traditional chemical treatment met...

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Problems solved by technology

The traditional chemical treatment methods are mainly lime or NaOH neutralization method and sulfide precipitation method. The traditional chemical method is simple to operate but the operating environment is harsh. There are many types of chemicals added, and it is difficult to control the effluent. The metal content in mud is low and there are many impurities, so rare and precious metal resources cannot be recovered

The electrocoagulation method has been widely used in recent years, but the electrocoagulation method has strict requirements on the influent water, the salt content of the influent water cannot be high, operation and maintenance are difficult, the consumption of the anode plate is large, the investment and operation cost is high, and resource recycling cannot be effectively realized

[0004] The existing industrial wastewater containing rare and precious metals only considers the standard discharge, and the treatment technology is to remove heavy metals from the water body, and produce a large amount of sludge, which causes secondary pollution to the environment, ignoring the resource utilization of heavy metals in wastewater

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