What material is used for the pump lining of fluorine-lined pumps?

Referring to fluoroplastics, they can of course withstand dilute sulfuric acid, and hydrochloric acid as well.

Fluorinated pumps are generally lined with F46, which is polyperfluoroethylenepropylene resin, abbreviated as FEP. Apart from being corroded by molten alkali metals, elemental fluorine, and aromatic hydrocarbons, this material remains inert in all other types of hydrochloric acid, sulfuric acid, nitric acid, aqua regia, organic acids, strong oxidizing agents, as well as in concentrated and dilute acids, alternating acids and bases, and various organic solvents – it is absolutely corrosion-resistant!

The fluoropolymer alloy mentioned on the 3rd floor refers to an alloy of F4 and F46, that is, an alloy of polytetrafluoroethylene and perfluoroethylene propylene, which is also widely used in the manufacture of pumps and valves! However, fluorine-lined pumps generally use F46 as the lining, rather than fluoropolymer alloys!

The main ones are F46 (perfluoroethylene propylene polymer), PVDF (polyvinylidene fluoride), and FRPP (reinforced polypropylene)

Among fluoroplastics, polytetrafluoroethylene has the highest consumption and the widest range of applications; it is an important type among fluoroplastics. The chemical structure of polytetrafluoroethylene is obtained by replacing all the hydrogen atoms in polyethylene. 1. Introduction: Polytetrafluoroethylene is commonly known as the \"king of plastics\". It possesses excellent chemical stability, corrosion resistance, sealing properties, high lubricity and non-stick characteristics, electrical insulation, as well as good resistance to aging. Capable of operating for extended periods at temperatures ranging from +250°C to -180°C, various polytetrafluoroethylene products have played a crucial role in various sectors of the national economy, including chemicals, machinery, electronics, electrical equipment, military industry, aerospace, environmental protection, and bridge construction. 2. Scope of application: Industries including chemicals, petrochemicals, oil refining, chlor-alkali production, acid manufacturing, phosphate fertilizer production, pharmaceuticals, pesticides, chemical fibers, dyes and chemicals, coking, gas production, organic synthesis, non-ferrous metal smelting, steel industry, nuclear energy, and the production of high-purity products (such as those produced via ion exchange membrane electrolysis). It is also applicable to the transportation and handling of viscous materials, as well as in food and beverage processing industries where high hygiene standards are required. Media: Hydrofluoric acid, phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, various organic acids, organic solvents, strong oxidizing agents, and other highly corrosive chemical media. Temperature: -20～250°C; sudden cooling and heating, or alternating hot and cold conditions are permitted. 　　-20–250°C (-4–+482°F). Pressure: -0.1–6.4 Mpa (from full vacuum to 64 kgf/cm2). 3. Advantages of polytetrafluoroethylene: Heat resistance – it can be used at working temperatures up to 250°C. 　　Low-temperature resistance – excellent mechanical toughness ； It can maintain a 5% elongation even when the temperature drops to -196°C. 　　Corrosion resistance – It exhibits inertness toward most chemicals and solvents, and can withstand strong acids, strong bases, water, and various organic solvents. 　　Weather resistance – it has the best aging life among plastics. 　　High lubricity – it has the lowest coefficient of friction among solid materials. 　　Non-adhesion – it has the lowest surface tension among solid materials, and does not adhere to any substances. 　　Non-toxic – it is physiologically inert, and there are no adverse reactions when used as an artificial blood vessel or organ for long-term implantation in the body. This post was last edited by lxzzl on 2008-7-30 11:16.]

Today’s fluorinated linings contain a lot of talc and other substances; they are not very pure. Of course, their price is low as well. But regardless of the type, they all possess corrosion resistance

Imported fluorine-lined pumps come in three types: ETFE/PFA/PVDF. In China, since these materials are not available, F46 has to be used instead.

Fluoroplastics are alkane polymers in which some or all of the hydrogen atoms have been replaced by fluorine; they include polytetrafluoroethylene (PTFE), perfluoro(ethylene propylene) (FEP) copolymers, polyperfluoroalkoxy (PFA) resins, polytrifluorochloroethylene (PCTFF), ethylene-trifluorochloroethylene copolymers (ECTFE), ethylene-tetrafluoroethylene (ETFE) copolymers, polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF). 　　Polytetrafluoroethylene is known by trade names such as “Teflon”, “Teflon”, “Teflon”, “Teflon”, and “4F”. It is a perfluoropolymer obtained through the free-radical polymerization of tetrafluoroethylene. Its molecular structure consists of linear repeat units of the C-F2-CF2 pattern; it is a crystalline polymer with a melting point of around 631°C and a density of 2.13–2.19 g/cm3. PTFE possesses excellent chemical resistance; its dielectric constant is 2.1, its loss factor is low, and it remains stable over a wide range of temperatures and frequencies. It has excellent mechanical properties ranging from low temperatures up to 550V. 　　PTPE has high impact strength, but its tensile strength, wear resistance, and creep resistance are inferior to those of other engineering plastics. Sometimes glass fiber, bronze, carbon, and graphite are added to improve its special mechanical properties. Its coefficient of friction is almost lower than that of any other material, and it has a high oxygen index. 　　PTFE can be made into pellets, condensed fine powder (0.2 microns), and aqueous dispersions. Granular resin is used for compression molding and plug extrusion ； Fine powder can be extruded into a paste form to create thin-walled materials ； The dispersion can be used as a coating and for impregnating porous materials. Pure PTEE products available in the U.S. market include Auimont USA’s AI-goflo brand, DU POut’s Teflon brand, ICI AInericas Inc.’s FI brand, and HOechstCelanese’s HOSaflon brand. 　　PTFE has a very high melt viscosity, which hinders the use of conventional melt extrusion or molding techniques. The molding and extrusion methods for granular PTFE are similar to those used for powdered metals and ceramics—compression followed by high-temperature sintering ； The fine powder must be mixed with processing aids such as naphtha to form a paste, which is then extruded under high pressure into a thin-walled material. The volatile processing aids are removed by heating, and finally sintering is carried out. 　　Perfluoroethylene propylene copolymer FEP is formed by the copolymerization of tetrafluoroethylene and hexafluoropropylene. 　　The melting point of FEP crystal is 580 °F, and its density is 2.15 g/CCC (grams per cubic centimeter). It is a flexible plastic, and its tensile strength, wear resistance, and creep resistance are lower than those of many engineering plastics. It is chemically inert and has a low dielectric constant (2.1) over a wide range of temperatures and frequencies. This material does not catch fire and can prevent the spread of flames. It has excellent weather resistance and a low coefficient of friction, and can be used from low temperatures up to 392 °F. This material can be made into granular products for extrusion and molding, into powders for fluidized bed and electrostatic coating, or into water dispersions. Semi-finished products include films and plates. Rods and single fibers. The FEPs available in the U.S. market include DuPont’s Teflon brand, Daikin’s Neoflo brand, and Hoechst Celanese’s IHoustaflow brand. www.seafar.cn Its main uses are in the manufacture of pipes and inner linings for chemical equipment as well as the cover layers of drums, and various wires and cables such as aircraft hook wires, pressurization cables, alarm cables, flat cables, and oil well logging cables. FEP films have been used as thin coatings in solar collectors. 　　Soluble polytetrafluoroethylene: PFA is a modified version of polytetrafluoroethylene; its operating temperature can reach 260 degrees. Perfluoroalkoxy resins: PFA resin is a relatively new type of fluoroplastic that can be processed by melting. 　　The melting point of PFA is approximately 580 °F, and its density is 2.13–2.16 g/cc (grams per cubic centimeter). PFA is similar to PTFE and FEP, but above 302°C its mechanical properties are slightly better than those of FEP, and it can be used at temperatures up to 500°F; its chemical resistance is comparable to that of PTFE. PFA is available in granular form for molding and extrusion, as well as in powdered form for rotational molding and coatings ； Its semi-finished products include films, plates, rods, and tubes. The PFA resins available in the U.S. market include Teflon from DUPOut, Neoflon from Daikin, Hthen from Ansimont, and Hostafl from HOechst Celanese. The uses of PFA are similar to those of FEP. 　　Polytrifluorochloroethylene PCTFE is a product of the polymerization of trifluorochloroethylene initiated by radicals, featuring a linear main chain composed primarily of repeating –CF(Cl)–CF units. 　　PCTFE is a crystalline polymer with a melting point of 425 °F and a density of 2.13 g/cm³ (grams per cubic centimeter). 　　At room temperature, PCTFE is inert to most reactive chemicals, but it can be dissolved by a few solvents at temperatures above 212°C, and it can also be swelled by certain solvents, especially chlorinated solvents. PCTFE has an excellent gas-barrier property, and its membrane products have the lowest water vapor permeability among all transparent plastic membranes. Its electrical properties are similar to those of other perfluoropolymers, but its dielectric constant (2.3–2.5) and loss factor are slightly higher, especially at high frequencies. PCTFE can be used to manufacture thick (1/8 inch) optically transparent parts. 　　Although PCTFE can be processed by melting, its high melt viscosity leads to a tendency for degradation, which deteriorates the properties of the processed products, making processing difficult. 　　PCTFE resin can be made into granules for molding and extrusion. The film thickness ranges from 0.001 to 0.010 inches, and it can also be made into rods and tubes. The PCTFE resins available on the U.S. market include 3M’s Kel-F brand, Daikin’s Daiflon brand, and Allied Signal’s Acfon brand. 　　Ethylene chlorotrifluoroethylene copolymer ECTFE resin is an alternating copolymer of ethylene and chlorotrifluoroethylene in a 1:1 ratio; it has a melting point of 464 °F and a density of 1.68 g/cm3. 　　This material performs well from low temperatures up to 330T, and its strength, wear resistance, and creep resistance are **higher than those of PTEE, FEP, and PFA. It resists most corrosive chemicals and organic solvents at room temperature and high temperatures. It has a low dielectric constant (2.6) and stable performance over a wide range of temperatures and frequencies. ECTFE does not catch fire and can prevent the spread of flames; when exposed to fire, it decomposes into hard carbon. 　　ECTFE can be made into granules for molding and extrusion, as well as into powdered products for rotational molding, fluidized bed coating, and electrostatic coating. It can be processed into foam products using chemical foaming methods in traditional extrusion equipment, and is suitable for use in computer cables. Semi-finished products include films, sheets, tubes, and single fibers. The ECTFE product sold by Ausimont USA is branded as Halar. 　　In the field of wires and cables, the most important applications are in pressure-rated cables and cables for public transportation vehicles. Fire alarm cables, anode protection cables. Injection-molded products include tower fillers, valve and pump components, connectors, wire terminals, and filter housings. ECTFE pipes are used as sleeves for optical fibers, unsupported pipes, linings for steel pipes, and reinforced plastic pipes. 　　ECTFE coatings and Uchimura can prevent metals from being eroded by the environment. Membranes are used in rational batteries and for isolation purposes. Applications of single fibers include oil mist eliminators, woven sleeves, and filtering fabrics. The wide-format (48in) ECTFE sheet with glass fiber backing can be used as a lining for tanks that require chemical resistance and high strength.