| Electroless is a surface treatment for the coating on matrix (metal or nonmetal), which is carried out by the reaction between oxidant and reductant in aqueous solution. Compared with the electroplating, Electroless can get a satisfactory coating for any shapes of workpiece, such as, which include the cavity, the deep hole, the pipeline, the groove, the corner, the crevice, etc, without external power supply. Electroless is widely applied to the fields of industry.The Electroless process of Ni-P-PTFE was based on the principle of Electroless Ni-P alloy. The surfactant and the whisking were employed to disperse the PTFE powder and to keep the stability of electroless solution. The chemical precipitation was used to deal with the waste solution of Electroless Ni-P-PTFE, and the nickel salt was to recycle from the waste solution.The pyrites was a main material for fabrication of sulfuric acid, there are over ten million pyrite cinder from the process of synthesis of sulfuric acid a year in our country, which gives rise to environmental pollution and waste of resources. The main components of the pyrite cinder are ferric oxide, ferrous oxide and silicon dioxide, respectively. In order to recycle the pyrite cinder and to resolve the problems of environmental pollution from pyrite cinder, synthesis of ferric chloride using the pyrite cinder had been studied in the thesis.This work mainly includes the following aspects:(1) The basic formula of solution and the best process parameters for Electroless Ni-P-PTFE had been founded.(2) The coating of Ni-P-PTFE has good adhesion, wearability, corrosion resistence and self lubricating.(3) The reclaim of nickel salt can reach to 96% from the waste solution of Electroless through adjusting the pH value of the solution and the process parameters.(4) The content of ferric chloride fabricated by two-step acid dissolution from pyrite cinder can reach to 40% and the content of arsenic or lead is below 20ppm in the ferric chloride. |
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