Graphite material for polysilicon ingot heat preservation thermal field and preparation method thereof

• Main Authors: PANG ZHONGHAI, ZHANG PEILIN, JI YONGLIANG, FAN ZHILI, QIAN JINGRONG, ZHANG PEIMU, LIU WEIKAI, CHI JIULIN
• Format: Patent
• Language: English
• Published: 17.06.2015
• Subjects: CHEMISTRY; COMPOUNDS THEREOF; INORGANIC CHEMISTRY; METALLURGY; NON-METALLIC ELEMENTS

The invention relates to a graphite material for a polysilicon ingot heat preservation thermal field and a preparation method thereof. The method comprises the following steps: crushing, sieving and burdening calcined coke, adding mid-temperature pitch and mixing, forming, primary roasting, primary dipping, secondary roasting, secondary dipping, tertiary roasting and graphitizing to obtain a finished product; the particle diameters and contents of the calcined coke are as follows: 1-2% of calcined coke with particle diameter larger than 0.5 mm while not larger than 0.8 mm, 35-40% of calcined coke with particle diameter larger than 0.5 mm while not larger than 0.35 mm, 27-31% of calcined coke with particle diameter larger than 0.35 mm while not larger than 0.075 mm, and 30-35% of calcined coke with particle diameter smaller than 0.075 mm; the mixing procedure is divided into dry mixing and wet mixing, the wet mixing procedure comprises: firstly heating the mid-temperature pitch to 180-230 DEG C, holding and stirring for 30-60 minutes, and then, adding the mid-temperature pitch into aggregate in twice for kneading, wherein the kneading temperature is 140-150 DEG C.