PTA Production Of Waste Cobalt And Manganese Catalyst Resources Recycling

The content of cobalt in the waste cobalt and manganese catalyst in the production of Pure Terephthalic Acid(PTA) was low and the content of manganese was high. The common cobalt and manganese separation methods generally were not suitable for this material and would make cobalt and manganese mixed with each other, leading to incomplete separation. The waste catalyst containing cobalt and manganese in PTA production was used as raw material, and three aspects of ammonia leaching separation of cobalt and manganese, liquid phase reduction method of cobalt products and prepared by roasting of manganese products were experimented.The content of cobalt and manganese in the raw material was measured by chemical titration and Inductively Coupled Plasma-Atomic Emission Spectrometry(ICP-AES). The relative deviation of these two methods for determining was in the range of ±2%.In the section of ammonia leaching separation of cobalt and manganese, the separation effects on cobalt and manganese of the methods of ammonia- carbonate – peroxide and ammonia- peroxide- sodium carbonate were studied respectively. The concentration of cobalt in the filtrate was measured by ICP-AES and manganese by Atomic Absorption Spectrometry(AA). The surplus rate of cobalt and deposition rate of manganese were calculated. And then separation effect of cobalt and manganese was analyzed. The experimental results show that, in the system of ammonia- ammonium carbonate – peroxide, the separation result of cobalt and manganese is better. The first step’s best reaction conditions are as follows, the stirring speed 200 r/min, the reaction time 8 h, the reaction temperature 20 ℃, the amount of ammonia 1.4 times of chemical stoichiometric coefficient, and the dosage of the ammonium carbonate 1.3 times of the measuring theory of chemical stoichiometric coefficient. And the second step’s best reaction conditions are as follows, the reaction time 8 h, peroxide dosage 1.6 times of chemical stoichiometric coefficient and pH 10.0. The residue rate of cobalt can reach 99.8%, and the deposit rate of manganese can reach 100%.In the section of liquid phase reduction method of cobalt products, hydrazine hydrate was used as reductant and sodium hydroxide as precipitator in the processing method of cobalt-ammonia complexation liquid. The effects on deposit rate of cobalt in these two steps were studied separately. The material structure and shape of cobalt products were characterized by X-Ray Diffraction(XRD) and Scanning Electron Microscope(SEM). The experimental results show that, the best reaction conditions are as follows, reduction temperature 80℃, dosage of hydrazine hydrate 1.0 times of the theory of the dosage, precipitation temperature 80℃, and the dosage of sodium hydroxide 4.0 times of the theory of the dosage. The high purity and flake beta- cobalt hydroxide can be prepared.Manganese products could be prepared by roasting the manganese carbonate precipitation produced in the process of ammonia- ammonium carbonate. The material structure and shape of manganese products from the different calcination programmes were characterized by XRD and SEM. The experimental results show that, high purity and relatively homogeneous manganous-manganic oxide can be obtained in the roasting program up to 900℃ and roasting 400 min thermostatically.Furthermore, the relevant disposals of nitric oxides(NOX), ammonia and waste alkali liquor produced by the whole recycling process were designed, and the effulent can achieve the environmental discharge standard.