Study On The Development And Technology Of Coal-tar Pitch Manufacture In WISCO

The present situation of the production and application of coal-tar pitches in China was introduced. Some factors affecting the market of coal-tar pitches were dissected. The application prospect and actual problems of modified pitches in the manufacture of carbon materials were explored.Two kinds of process technology of medium pitch and modified pitch were valued comprehensively. The comparison was made between the still-type thermal polymerization and vacuum flash distillation. Coal-tar pitches produced by two kinds of polymerization processes had different structures and properties.The necessity of de-residue of the coal-tar in WISC (Wuhan Iron and Steel Company) was explored. The working principle of high speed centrifugal machine from Germany was introduced. The effect of de-residue treatment of the coal-tar on the quality index and composition of coal-tar pitches was analyzed. Some measures to solve the technology problems in the production of modified pitches were suggested.The reason resulting in the quality problem of modified pitches from WISC (Wuhan Iron and Steel Company) was analyzed. The lower TI(toluene insolubles) content of modified pitches was caused by the low TI content medium pitches. The quality fluctuation of coal-tar brings about the reduction of TI content of medium pitches. The reasons of quality fluctuation of coal-tar from WISC were analyzed. This becomes an important basis for solving the quality problem of modified pitches.The process programs to raise TI content of medium pitches were selected. According to the character that the variation of TI constituent content and softening point of modified pitches during thermal polymerization is inconsistent, the process technology of flash oil return was used to increase the TI constituent content of modified pitches. Actual production had showed that it improves effectively the quality of modified pitches.