Industry News

- November 05, 2020

Types of impregnated products

(1) Small size graphite electrodes and joint blanks, various sizes of graphite anodes, fine structure, high strength and high density graphite. These products must have higher density, strength, and lower resistivity, so the roasted semi-finished products are first impregnated with coal pitch and then graphitized.

(2) Graphite anode of diaphragm type salt solution electrolyzer. Graphite anodes that have been impregnated with coal pitch once can generally be used for 8-9 months. Graphite anodes that are not impregnated can usually only be used for 5-6 months. The main reason for affecting the service life of graphite anodes is that the electrolyte enters the pores of the anode Permeate, and the hydroxide ions, sulfate ions, and hypochlorite ions in the electrolyte discharge on the anode to produce nascent oxygen. The nascent oxygen oxidizes the anode to cause chemical corrosion. This chemical corrosion accounts for about half of the loss, and the chemical corrosion weakens the bond between the coke particles, resulting in the phenomenon of particle peeling and slagging. The higher the porosity of the product, the more serious the chemical corrosion and slag drop.

(3) Impermeable graphite for chemical equipment. Since graphite products are porous materials, liquids and gases are easily permeated. It can be impregnated with organic resin (such as phenolic resin, furfuryl ketone resin), and the resin is cured at an appropriate temperature after impregnation, so that the permeability of liquid and gas to graphite products can be reduced to the required level, and the mechanical strength is also It can be improved without reducing the thermal conductivity of the product. This kind of impermeable graphite chemical equipment with good corrosion resistance and good thermal conductivity is widely used.

(4) Wear-resistant carbon and graphite materials and products. When the working temperature and working medium do not allow the use of lubricating oil and other liquid lubricants, piston rings, seal rings, bearings, etc. made of graphite and other carbon materials can be used without lubricants to ensure long-term operation of the machine at high temperatures . This kind of graphite or carbon wear-resistant material needs to have higher density, hardness and compressive performance, so it generally needs to be impregnated with synthetic resin or low melting point metal (such as aluminum alloy, tin alloy, lead bronze, babbitt alloy).