Filtration is the physical process of separating a substance from a substance. Its morphology is divided into three types: gas-solid, liquid-solid and solid-solid
Separation, the most widely used is liquid-solid separation, which is accomplished through the combination of filter press and filter cloth.
With the growth of GDP in recent years, domestic demand for non-ferrous metals has been strongly supported. Filtration is an important process in nonferrous metal production
Link, the target substance or the target substance compound is separated from its mineral, how to effectively, efficiently, low energy consumption
Separation has always been a key issue in the smelting industry. The successful use of horizontal band filter – filter cloth effectively improves the level of filtration technology.
Horizontal band filter is suitable for liquid-solid separation of mixtures in desulfurization, metallurgy, chemical industry, coal washing, food and other fields in power plants. Belt type
The filter equipment has the advantages of high filtration efficiency, large production capacity, good washing effect, wide application range and simple operation, so it is widely used in China
The favor of industrial manufacturers.
1. Horizontal band filter — a brief introduction to filter characteristics
1.1 filtration mechanism of belt filter
Horizontal band filter is a new type of liquid-solid separation equipment with high automation
The liquid – solid separation is realized by utilizing the gravity and vacuum suction of slurry.
Belt filter – filter cloth features:
1.2.1 high filtration efficiency. Using the horizontal filter surface and upper feeding, the large particles will first sink at the bottom, forming a layer of filter layer, so that filter cake
Reasonable structure, less clogging of filter cloth, less resistance and higher efficiency.
1.2.2 good washing effect. The best washing effect is obtained by using multistage countercurrent washing method, and high quality filter cake is obtained
1.2.3 the thickness of filter cake can be adjusted. Low water content, easy to discharge, filter cloth thickness can be adjusted according to material needs to improve production capacity.
1.2.4 the front and back of the filter cloth can be cleaned at the same time. The front and back of the filter cloth are effectively cleaned when regenerating, so as to remove the clogging of the filter cloth and prolong the service life of the filter cloth
1.2.5 high degree of automation. Feeding, filtering, washing, unloading and cloth cleaning are all continuous automation, improving production efficiency and reducing labor
2. Development and application of belt filter cloth
2.1 development of belt filter cloth
Filter belt is one of the core technology of filter. The filtration process is the separation process of material by filter cloth. Filter cloth is used in a variety of industries
The development is to filter the process as the service target, to use the conditions for material selection, yarn shape, organizational structure, after finishing methods and other four
Face to face coordination.
2.1.1 material selection of the filter belt
Material selection is based on the use temperature, acid and alkali value, the corresponding textile materials are selected. Usually follow high – temperature strong alkali with polyamide, high – temperature acid
The principle of selecting polyester for sex and polypropylene for normal temperature. The physical and chemical properties of three common materials are described below.
Physical and chemical properties of commonly used materials table 1
Variety name polypropylene polyester nylon
Fracture strength (CN/dtex) 3.2 ~ 7.0 4.0 ~ 9.0 4.5 ~ 7.8
Fracture elongation (%) 20 ~ 45 15 ~ 35 20 ~ 35
Good acid resistance, strong acid resistance
Good alkali resistance and weak alkali resistance
Solvent resistance insoluble in general solvents insoluble in general solvents insoluble in general solvents
Heat resistance softening point: 140 ~ 165 ℃
Melting point: 160 ~ 177 ℃ softening point: 238 ~ 240 ℃
Melting point: 255 ~ 260 ℃ N6: softening point: 180 ℃
Melting point: 215 ~ 220 ℃
N66: softening point: 230 ℃
Melting point: 250 ~ 260 ℃
Poor sun tolerance
Good wear resistance, optimum
2.1.4 post-treatment of the filter belt
After finishing is the filter belt performance of the assembly, is the designer’s concept of experience, filter belt production process pre-stress release, dynamic balance experience.
The commonly used methods include heat finalization, surface calendering, etc. According to the surface flatness of the filter belt, yarn binding force, tissue stability, target feel, etc
The determined. It’s the embodiment of experience and ideas.
2.3 application of filter belt
Filter belt is mainly used in metallurgy, chemical industry, environmental protection and other industries. The physical performance and service performance of the filter band meet the requirements of the user
2.3.1 metallurgical industry
It is mainly used in the filtration of superfine flame retardant additives, species division and carbon division sequence of special alumina
Filtration, gold smelting, fine copper and other processes.
2.3.2 chemical industry
It is mainly used in liquid solid separation of white carbon black and black carbon black, filtration of feed additive ZnO, catalyst, calcium phosphate and other processes.
2.3.3 environmental protection industry
It is mainly used in desulfurization and sewage treatment of power plant, paper making, metallurgy and chemical industry.
3. Development resistance
The development and promotion of filter belt are mainly restricted by spinning material, spinning machine and information.
3.1 material constraints
With the promotion of belt filter, more industries and processes will be used, and more stringent requirements on materials. Conventional spinning cannot meet the demand
PPS, NOMEX and other new spinning materials have few yarn products on the market, only fiber products, the development of elbow-weaving filter cloth.
3.2 restrictions on the spinning machine equipment
The filter cloth market is a special market with small quantity and many kinds of products. There has not been a professional spinning machine manufacturer to pay attention to its demand
Production plants are using conventional equipment or self-improvement, when weaving filter cloth, it is often the use of equipment capacity to meet the requirements of designers, so that
Step and compromise are often the choices of designers.
3.3 insufficient information interaction
At present, the promotion of filter cloth is the interaction between filter cloth and filter manufacturers. There is little communication between filter mill owners and filter cloth designers.
If the filter belt designers interact, we believe that the filter cloth industry will develop and update faster.
China has the world’s largest sulfur dioxide emissions, and power plants account for about 50 percent of the total sulfur emissions, sulfur dioxide emissions seriously polluted cities
In recent years, China has stepped up efforts to control sulfur dioxide emissions. The flue gas desulfurization project has been put into operation
The technical direction of desulfurization is mainly flue gas desulfurization.
The filter belt has been widely used in the field of filtration and has a good development prospect. Strengthen the theory, material, technology in the field of filtration.
The research and discussion of the technology will promote the structural adjustment of the filter products and play its due role in improving the technical content of the filter cloth in China.
Post time: Jul-25-2018