Talking about the treatment method of electroplating sludge and the type of anticorrosive pump
Research on the recovery and solidification of heavy metals in electroplating sludge is very necessary. Generally, after leaching heavy metals, the heavy metals are separated by precipitation method, and then the leached metal residues are solidified to improve resource utilization. Plating sludge
Research on the recovery and solidification of heavy metals in electroplating sludge is very necessary. Generally, after leaching heavy metals, the heavy metals are separated by precipitation method, and then the leached metal residues are solidified to improve resource utilization.
Source of electroplating sludge
Electroplating sludge is a solid waste that must be generated during the treatment of wastewater in electroplating plants. At present, the common method for treating electroplating wastewater is to add lye to it to promote its precipitation. This is also one of the main sources of electroplating sludge.
Most of the domestic electroplating plants use lye precipitation to treat wastewater, which will inevitably produce metal hydroxides, which will form electroplating sludge after dewatering by sludge pressure filtration.
Reducing agents, acids, alkalis, oxidants and other chemicals are added to the treatment of electroplating wastewater, so there are many types of substances in electroplating sludge and their components are also very complicated.
The electroplating sludge is divided into two types of mixed sludge and separated sludge according to the coarse-grained methods of electroplating wastewater. Mixed sludge refers to unified coarse particles after the sludge collected through different processes and links are concentrated; separated sludge Sludge is the treatment of different electroplating wastewater. Sludge contains certain major heavy metals.
1. Resource utilization technology
One of the research hotspots of resource utilization technology is to find a method of recycling electroplating sludge with simple operation, low cost and good effect.
Common resource utilization technologies include wet extraction, fire extraction, and manufacturing of building materials. Wet extraction: Chemical methods are used to separate heavy metal substances leached from electroplating sludge, and ensure that heavy metals can stably exist in solution. Acid, alkaline and neutral are the three common leaching agents.
In the electroplating sludge, most of the heavy metals exist as hydroxides, so the application of neutral leaching agents is less.
It is understood that common alkaline leaching agents, including sodium carbonate, ammonium carbonate, and ammonia, are relatively selective, but this method does not guarantee that all metals can be leached. Common acidic leaching agents include nitric acid, hydrochloric acid, and sulfuric acid. Different acid concentrations will produce different leaching effects, so it is necessary to find a suitable method according to the characteristics of electroplating sludge.
Precipitation method, reduction method and extraction method are three common wet extraction methods for heavy metals.
Wet extraction of heavy metals has very good results. It is widely used in the recovery of heavy metals in electroplating sludge, and it is also the most important method for resource utilization.
Fire extraction: Decomposes electroplating sludge under high temperature conditions and recovers heavy metals. Commonly used fire extraction methods include calcination, ion arc, incineration, and microwave. It can also be heat treated with carbon to create high temperature conditions.
High temperature treatment can reduce the volume of electroplating sludge and effectively reduce some of the toxic substances. It can promote the reaction of metal substances to form compounds or simple substances. It can also combine the methods of fire extraction and wet extraction to jointly extract electroplating sludge. Heavy metals.
However, the use of fire extraction must have a heating process, which is likely to bring heavy metal smoke pollution, which is also a problem that should be avoided and valued during use.
Manufacturing of building materials: One way to treat electroplated sludge is to make it into a building material, such as adding it to cement. This is a relatively low cost and ideal method, but it is still in the experimental stage.
There are currently cases where electroplating sludge is used in the manufacture of red label bricks. But confirming whether the leaching toxicity in the brick meets the standard is the key to further promoting this method.
2.Cure treatment technology
Solidification treatment is the last step of electroplating sludge treatment, the purpose is to keep heavy metals in an inert state, reduce the danger, and finally landfill treatment.
Solidification is the process of using additives in sludge to make the sludge into a tight, non-flowable solid, which is achieved by changing the strength, permeability and compressibility of the waste.
Common ways to solidify pollutants include lime curing, cement curing, thermosetting material curing, large-scale encapsulation curing, and glass curing.
The solidification treatment includes four basic steps. The first is to pre-treat the waste, that is, to dry, sort, and destroy the oxides; the second step is to add a curing agent to it; the third is to solidify and mix; the fourth is to It undergoes final processing.
The development of solidification technology for heavy metals in electroplating sludge is gradually showing a diversified trend, and the effect is gradually stabilizing, and it is developing towards industrialization.
3. Off topic, what kind of anti-corrosion pump is generally used to transport these media? Reducing agents, acids, alkalis, oxidants and other agents are added to the treatment of common electroplating wastewater. GM diaphragm metering pumps, CQB-F fluoroplastic magnetic pumps
are used for transportation. Common alkaline leaching agents include sodium carbonate, ammonium carbonate and ammonia. There are LHF fluorine-lined centrifugal pumps
, LZB fluorine plastic self-priming pumps
, and LFK fluorine-lined slurry pumps
. Common acidic leaching agents include nitric acid, hydrochloric acid, and sulfuric acid, such as LHC fluorine-lined magnetic pumps, LYH fluorine plastic submersible pumps
, and LFJ fluorine-lined crystal slurry pumps. The liquid alkali can be conveyed by LHJ stainless steel alkali pump
, IHL stainless steel centrifugal pump, etc.