Electroplating sludge mainly comes from solid waste generated by industrial electroplating plants, which is mainly produced through liquid-phase chemical treatment of various electroplating waste liquids and electrolytes. Electroplating sludge has a high water content and complex composition, especially with heavy metal hazards. Therefore, reducing, harmless, and resourceful disposal of electroplating sludge is currently the focus of electroplating sludge disposal.

The reduction of electroplating sludge mainly adopts the drying method, which dries the electroplating sludge with a moisture content of about 75% to a moisture content of about 10% (fully dried) or to a moisture content of about 30% (semi dried), in order to achieve the requirements of reduction, and then proceeds to the next step of smelting and extracting metals such as iron, copper, and zinc. The drying of electroplating sludge has the following characteristics and requirements: the material is sticky and has poor fluidity; High moisture content, slow drying speed, and high energy consumption; The exhaust has an odor and needs to be treated; The material requires uniform heating, a good operating environment, and can meet the target requirements in one go. Electroplating sludge is quantitatively and continuously fed into the feeding port of the dryer by a shaftless screw conveyor. After entering the blade, the material is flipped and stirred by the rotation of the blade, constantly changing the heating interface. It comes into contact with the body and blade and is fully heated, causing the surface moisture contained in the material to evaporate. At the same time, the material is transported in a spiral trajectory towards the discharge port with the rotation of the blade shaft, and continues to stir during transportation to evaporate the water seeping out of the material. Then, the uniformly dried qualified products are discharged from the discharge outlet. The gas containing water vapor and a small amount of ultrafine solid particles is sent to the water film spray washing tower, and the filtered gas is sent to the sewage treatment unit after water cooling and settling. The solid materials that come out can be directly transported and buried.

  Design Basis, Principles, and Process Selection of Electroplating Sludge Drying Machine

1. Design Basis

(1) Relevant information and requirements provided by the user
(2) Quantity of sludge:~ 200T/d
(3) Initial moisture content of sludge: 70%
(4) Moisture content to be dried: 40%
(5) Heat source: 0.5-0.6Mpa saturated steam
(6) Steam temperature:~ 160℃
(7) Air outlet temperature: 70-80 ℃
(8) Installation location: Indoor
(9) Power supply: 380V 50HZ three-phase four wire
(10) Control System: General Control Requirements
(11) Transmission method: gear transmission

  2. Design principles

(1) Adopting efficient, energy-saving, and simple process methods, we strive to achieve the goals of low energy consumption, low investment, minimal land occupation, convenient operation and management, and high sludge drying efficiency in the sludge drying system;
(2) The equipment, materials, and electrical components are made of well-known manufacturers' products with reliable quality;
(3) Adopting practical and feasible technological means, improving equipment level, and achieving automated operation in production as much as possible to ensure the reliable and economically reasonable operation of the sludge drying system;
  
  3. Process selection
  
  3.1 Design scale and processing requirements
  
(1) Design scale
According to the information provided by the owner, the designed processing capacity is approximately 200T/24h.

(2) Basic Design Conditions and Requirements
Based on the determined design scale, the basic conditions and requirements for the sludge drying system are shown in Table 2-1:

So whether it is landfilling, incineration, agricultural utilization, or thermal energy utilization, sludge drying is an important first step, which makes sludge drying play an increasingly important role in the entire sludge management system. Since the 1990s, the use of sludge drying technology to treat urban sludge has developed rapidly.