Treatment method for electroplating wastewater and sludge

Abstract

The invention discloses a treatment method for electroplating wastewater and sludge. The treatment method comprises the following steps: (1) evaporating and concentrating electroplating wastewater, discharging condensed water or recycling the condensed water to an electroplating process, and mixing and slurrying the concentrated solution, electroplating sludge and a carbon source; (2) carrying outmicrowave hydrothermal treatment on slurry under the conditions that a temperature is 130-250 DEG C and a pressure is 2-10 MPa so as to allow a carbon source and metal elements in the slurry to reactin situ to generate a carbon-based catalyst; (3) introducing an oxidant, carrying out catalytic wet oxidation on the slurry having undergone hydro-thermal treatment, carrying out solid-liquid separation after the reaction is finished, carrying out drying treatment on a solid phase, and recycling the treated solid phase as a catalyst; and (4) carrying out electric flocculation on a filtrate obtained by solid-liquid separation, wherein solid slag of electric flocculation is partially recycled to the electroplating sludge. According to the method, deep harmless and reduction treatment of the electroplating wastewater and the electroplating sludge is realized, and meanwhile, the recyclable catalyst for wet oxidation wastewater treatment is obtained through resource utilization.

Description

technical field [0001] The invention relates to the field of wastewater and sludge treatment, in particular to a treatment method for electroplating wastewater and sludge. Background technique [0002] The composition of wastewater produced in electroplating production is very complex, except for cyanide (CN - ) and acid and alkali, heavy metals are potentially extremely harmful sewage categories in the electroplating industry, and these substances seriously endanger the environment and human health. The main sources of electroplating wastewater are: (1) Plating parts cleaning water (the main source of wastewater). In addition to containing heavy metal ions, the waste water also contains a small amount of organic matter, which is relatively low in quantity but relatively large in quantity; (2) the discharge of plating solution filtering flushing water and waste plating solution. The amount of this part of wastewater is not large, but the content is high and the pollution i...

AI Technical Summary

Problems solved by technology

The most commonly used method is the chemical precipitation method, but a large amount of sludge containing heavy metals and organic matter will be produced during the reaction process, and the heavy metals will be transferred from the wastewater to the sludge, causing secondary pollution

Although the commonly used ion exchange method has strong selectivity of ion exchange resin, the manufacture of ion exchange resin is complicated, the cost is high, the consumption of regenerant is large, and the operation and management level is high. Organic substances such as organic substances, which will cause greater pollution to the resin, and the waste water cannot be discharged up to the standard without subsequent treatment

Adsorption treatment method, the price of the adsorbent is relatively expensive, and the adsorbent needs to be regenerated and the secondary pollution is large, which restricts the wide application of adsorption technology

In the current electroplating wastewater treatment, the reverse osmosis method can recover the electroplating solution, thereby achieving better economic benefits; but the osmotic membrane used in the reverse osmosis method is delicate, and the solutes and suspended solids in the electroplating wastewater are complicated, and most of them are acidic or Alkaline, it is easy to cause blockage and damage of the permeable membrane, resulting in a waste of social wealth

[0004] Because the chemical precipitation method is commonly used in the treatment of electroplating wastewater, a large amount of electroplating sludge will be produced. The electroplating sludge mainly adopts the following three treatment methods: one is harmless treatment and disposal. After the sludge is solidified, the sludge will not Cause secondary pollution and then discard or store, but this technology needs to occupy a large amount of land resources, and after curing, the capacity will increase, and the transportation cost will increase; the useful metals in the sludge cannot be reused, resulting in waste of resources

The second is the resource utilization of sludge, using pyrotechnics and wet techniques to extract and recycle heavy metals in sludge, or using electroplating sludge as a raw material to prepare other materials, but due to the low calorific value of electroplating sludge, it generally requires The use of fuel consumes more energy and the incineration process is likely to cause secondary pollution; wet technology is relatively low in cost and less in secondary pollution, but the current wet technology has poor selectivity to copper, nickel, and chromium, resulting in recycling low rate

The third is the leaching method. Through selective leaching of electroplating sludge, the heavy metal components in it are dissolved, so as to realize the separation and enrichment of valuable metals; the leaching method has the advantages of simple process and high metal recovery rate, but it is ubiquitous The relative deviation of selectivity and the problem that the waste liquid is difficult to deal with

[0005] In addition, electroplating wastewater and electroplating sludge are usually treated separately, the treatment process is cumbersome, and additional oxidants or catalysts need to be added in various treatment processes, the treatment cost is high, and the treatment efficiency is low