The invention discloses a method for preparing high-purity
cadmium telluride. The reaction process is carried out in a closed
quartz tube with
melting point above
cadmium and
tellurium and after
carbon coating treatment, wherein the
mass ratio of a 5N
cadmium material to a 5N
tellurium material is 1: 1.1-1.15. The method comprises the following steps: dividing the weighed
tellurium material into N parts according to the charging times N, dividing the weighed cadmium material into N-1 parts, alternately adding each part of tellurium material and each part of cadmium material into the
quartz tube and adding the tellurium material into the
quartz tube firstly and lastly, removing
oxygen after charging,
sintering and sealing the tube by using a sealed
bulb, and slowly performing high-temperature and high-pressure synthetic reaction. The method has the advantages that the contact area of the raw materials is larger in a
molten state, the
reaction speed is more sufficient compared with the
solid raw material, the micro-sized crushing treatment for the raw materials is avoided, the shape requirement of the raw materials is relaxed, the preparation cost is greatly reduced, the purity of the
raw material is ensured, the method is suitable for large-scale production, the synthetic conversion rate of the cadmium
telluride can reach 98 to 99.5 percent, and the single-tube yield of 800 to 1,000 grams can be ensured by using the quartz tube with the inside
diameter of 32 millimeters under the premise of safety.