The process of graphite impregnation is to fill the pores of carbon graphite materials with different forms of carbon. The purpose of the dense and impregnated graphite impregnation process is to produce high density products,
High density of liquid penetration. However, the densification is limited, it is impossible to require all the pores of dense products, but only A layer that is not dense enough for the product. Deposited on the surface of the graphite carbon covered layer, can significantly change the performance of another, because
The deposited carbon layer becomes another working surface. The characteristics of the dense carbon layer will be described below. Two, the need to dip the product of 1 small size graphite electrode and joint blank, a variety of graphite anode. These products have a high density and strength, low resistivity, so the first half of the finished product is soaked with coal tar and then graphitized. After coal asphalt impregnated a product the product volume density from 1.55 g / M 3 to about 1.65 g / cm 3, porosity decreased from 25 ~ 32 to 22 ~ 25%, the compressive mechanical strength can be increased to around 9.8 MPa, the resistivity can be decreased by about 10%.
For the requirements of high strength and high density products after two, three or four times (after repeatedly dipping roasting, baking again after impregnation), can make products to capture the high volume density of 1.85 g / cm'3, porosity decreased 116% compression! Strength increased to 39.2 MPa. 2 the production of high quality graphite anodes used in diaphragm salt solution electrolysis cells. After impregnation with coal tar graphite anode, the general can make the kitchen 8--9 months, not impregnated graphite anode can only be used for 5 - 6 months. The main reason is the influence of graphite anode life to the anode electrolyte penetration hole, and hydroxyl ions, sulfate ions and hypochlorite ions in the electrolyte in the anode discharge produces nascent oxygen.
According to the relevant information, some of the oil impregnated anode service life doubled. But too much oil will cause the deterioration of the operation of the electrolyzer, the use of high current density of the mercury electrolytic tank, but there is no oil immersed anode 3 chemical equipment requirements of impermeable graphite. Graphite is porous material, so the liquid and vapor can penetrate, available organic resin (such as phenolic resin, furfural acetone resin impregnated graphite products processing) in advance well, and after immersion in the appropriate temperature curing of the resin, can make liquid and gas of graphite products to low permeability in fact, the degree of harm, but also improve the mechanical strength of several times, and products, thermal conductivity is not reduced. This corrosion resistance, good thermal conductivity of the impermeable graphite chemical equipment is widely used.
