Method for recycling waste mercury catalyst from polyvinyl chloride production based on calcium carbide method

Abstract

The invention provides a method for recycling a waste mercury catalyst from polyvinyl chloride production based on a calcium carbide method. The method comprises the following steps: smashing the waste mercury catalyst with mercuric chloride, hydrogen chloride and vinyl chloride attached to activated carbon into certain fineness; extracting with carbon disulfide and filtering, thereby acquiring filter residues; heating and then condensing the filter residues under a light-shielding condition to recycle mercuric chloride; treating the filter residues with alkali, neutralizing the absorbed hydrogen chloride, filtering, drying and recycling the activated carbon. The recycling method provided by the invention has the advantages that the heating temperature for recycling the mercuric chloride is low, the recycling of the mercuric chloride can be carried out only at 90-120 DEG C, the recovery rate reaches up to 95% and the purity reaches up to 99.5%; after the recycled activated carbon is treated, the purity is high, the recovery rate reaches up to 92%, the absorption activity is recovered, the micro-pore surface area is recovered to 1000-1200m<2>/g and the pore volume is recovered to 0.3-0.6ml/g; besides, according to the method, the operation is simple, the energy consumption is low, the environment-friendly and pollution-free effects are achieved; the organic substances, such as chloroethylene, and the hydrogen chloride acidic material can be effectively removed.

Description

technical field [0001] The invention relates to the field of catalyst recovery, in particular to a method for recovering waste mercury catalysts in the production of calcium carbide polyvinyl chloride. Background technique [0002] In the production process of polyvinyl chloride by calcium carbide method, acetylene and hydrogen chloride are used as raw materials, mercuric chloride and activated carbon are used as catalysts to carry out catalytic reaction to synthesize vinyl chloride monomer, and then the vinyl chloride monomer is polymerized to form polyvinyl chloride. With the progress of the catalytic reaction, the content of mercuric chloride which is easy to sublimate in the activated carbon is reduced to less than 4%. At the same time, the catalyst is gradually deactivated due to the adsorption of excess raw hydrogen chloride gas and product vinyl chloride in the pores of the activated carbon. As my country's environmental protection requirements are becoming increasing...

AI Technical Summary

Problems solved by technology

In the prior art, recovery of waste mercury catalysts is usually done by steaming waste mercury catalysts together with lime water to convert mercuric chloride into mercuric oxide, and then turn mercuric oxide into elemental mercury at a high temperature of 700-800°C. The recovery rate of this method is low. It is only about 57%, and the energy consumption is large; there are also poisonous chlorine gas reclaimed mercury and mercuric chloride in the heating process, and the final dry distillation tail gas is treated to regenerate mercury-containing wastewater and pollute the environment; Adsorbed organic substances and hydrogen chloride acidic substances are effectively removed, affecting the quality of recovered substances