The Reclaimation Methodologies Of The Waste Computer Boards And Blocks

In this thesis, the reclaimation methodologies of precious metals such as gold, silver, palladium and platinum, and nonferrous metals such as copper and lead in the waste computer boards and blocks were studied and presented, the economic effectiveness and environment protection concerned in the processes of dealing with the waste computer boards and blocks were discussed.The concrete reclaimation methodologies were: (1) A process flow including pretreatment - nitric acid processing - chlorazolic acid dissolving gold - reduction, step by step were presented, the reclaimation rate of gold powders was 94.5% and their purities from two steps of reduction were above 99.95%. (2) A process flow including pretreatment -extracting gold and silver by air blast cyanidation processing - reduction - disparting silver by nitric acid - obtaining gold, step by step were presented, the reclaimation rate was 57.5% under the condition of 20 hours air blast cyanidation and the particle size less than 60 mesh.The reclaimation methodologies of silver from pretreated computer boards and blocks powders, using retreat silver by nitric acid - silver oxide intermediate product method and retreat silver by chlorazolic acid - silver oxide intermediate product method, were studied, and a process flow on above methods were presented. The obtained silver was 225g from the 20kg the pretreated boards and blocks powders by the former and the reclaimation rate of silver was 93.7%, and the purity of sycee was 99.96%, reached the No.2 state standard silver. The obtained silver was 198g from 20kg pretreated computer boards and blocks powders by the latter and the reclaimation rate of silver was 82.5%, and the purity of sycee was 99.96%, reached the No.2 state standard silver.Two kinds of fine chemicals of palladium using the method of dispart silver by nitric acid - ammonia or ammonia chloride precipitate palladium were obtained, and a process flow on above method was presented.Platinum from the filtrate of reclaimed gold using nitric acid - chlorazolic acid method were obtained and a qualitative analysis result suing SnCl2 spectrophotography was founded. Copper was reclaimed by ammonia - ammonium chloride extract copper method and lead was reclaimed using pyrometallurgy method in which zirconium was by produced. The reclaimation rate of copper was 93.9% and that of lead was 93.3%. The matter phase of the byproduct powders of ZrO2 was identified.