The electroplating sludge refers to the precipitates produced by the electroplating wastewater treatment process, with copper, chromium and other heavy metal hydroxides as the main components, and the components are complex. Due to the large amount of electroplating wastewater, complex composition, high COD, and high heavy metal content, any discharge without treatment will cause serious environmental pollution. When treating electroplating wastewater, a large amount of electroplating sludge will also be formed. These electroplating sludges have the characteristics of high water content, high thermal stability of heavy metal components, and easy migration. If not properly handled, it will easily cause secondary pollution.
The general production process of the electroplating industry is composed of three parts: the first part is the pretreatment process, which cleans and activates the metal surface, and its processing steps include degreasing, cleaning, acid leaching, cleaning, etc .; the second part is the electroplating process, which uses the electrochemical process A thin layer of metal is deposited on the surface of the conductive workpiece; the third part is the post-treatment process, which mainly includes cleaning and drying. In the entire production process, the workpieces in the pre-treatment stage and after electroplating need to rinse the plated parts with a large amount of water, thereby forming electroplating wastewater.
The waste water generated after the derusting and cleaning of the plated parts is generally acidic waste water. The waste water formed after the plating of the plated parts is mainly containing trace metal elements, such as copper, chromium, nickel, zinc, cadmium and organic metal brighteners.
According to the nature and characteristics of the wastewater generated during the electroplating production process, there are different treatment methods for electroplating wastewater with different metal ions. Generally speaking, electroplating wastewater is generally treated by acid-base neutralization and flocculation sedimentation. Wastewater containing metals such as chromium and nickel is ionized with excess alkali solution to form hydroxide precipitates, which are naturally precipitated or filtered Separate it from water. The electroplating wastewater containing zinc is precipitated at a pH value of about 8.5, because zinc hydroxide is an amphoteric compound and can be dissolved by acidity or overbasicity. The deposits formed after the treatment of electroplating wastewater by these methods are called electroplating sludge.
The sludge dryer, also known as sludge energy-saving drying system, is a process and system that uses a variety of energy sources to efficiently and low-cost dry sludge. It is to dry the dehydrated sludge water content from 70 ± 10% Reduced to 20 ± 10%. Sludge has the characteristics of poor fluidity, high viscosity, easy agglomeration, and difficult to evaporate water. It is more difficult to dry and requires higher drying process.
Dryfree sludge dryer is a new type of high-temperature heat pump sludge dryer, which can be operated around the clock. When the outdoor air temperature is high, the air can be used for drying, and the air source heat pump can provide heat to the dryer. Low operating cost, no pollution, energy saving and environmental protection, it is very suitable for electroplating sludge drying and treatment.
Post time: Jul-09-2020