To Mention The Of Vanadium New Technology From The Waste Vanadium Catalyst

In the modern industry, there are a lot of catalysts used in the oil refining, chemical engineering, and metallurgy. It is estimated that more than 500-700 ten thousand tones of spent catalysts which contain vanadium are annually generated by the whole world. It is significance to recover vanadium from spent catalysts for resource utilization and environmental protection.It mainly researches how to recover vanadium from spent sulphuric acid catalysts, and how to recover vanadium and molybdenum from spent petrochemical catalysts.The spent sulphuric acid catalysts contain 3%-5% vanadium and some S and Fe which are major impurities. With the process that is leaching with sulphuric acid-extracting with P204- stripping with sodium bicarbonate solution- deposit vanadium with ammonium chloride- calcinations, the purity of obtaining V2O5 achieved above 99%, up to 99% powder vanadium standard.The influential factors of the leaching rate, like pH value, the concentration of sulphuric acid, the ratio of liquid to solid, and time, have been studied. The vanadium can't be leached in the neutrality solution. The ratio of liquid to solid and leaching time nearly don't have the influence on leaching rate. The concentration of sulphuric acid obvious has influence on leaching rate. But when the concentration outclass of 50g/L, the leaching rate would decreasing. The best leaching rate of vanadium can reach to 95% as the concentration of sulphuric acid is of 50g/L, the ratio of liquid to solid is of 1.5:1, the leaching time is 30 minute, and churning in the room temperature.The influential factors of the extraction rate of vanadium, including the concentration of P204, pH, and the degree of saponification, have been studied. Base on the data of experiments, the extraction isothermal of vanadium can be obtained. The cycling use times of extractant and the maximum adsorption capacity of vanadium are studied too. The pH value influence on the extractionrate most. When pH value is of 1-2, the extraction rate reaches to tiptop. The extraction rates increase with the concentration of extractant, but stop at 20 vol.%. The extraction rates increase obviously after saponification. P204 can strongly extraction vanadium and cycling use time after time. The best extraction rate of vanadium can reach to 80% as the extractant consisting of 20 vol.% P204, extraction balances pH about 1-2, the organic phase must be saponified before extraction when the concentration of vanadium in liquor is 4.5g/L(O/A=1:1).The pH value also influence stripping rate. And the impurities of organic phase, stripping agent, and the concentration of stripping agent influence on the stripping rate most When the loaded-extractant does not contain impurities, the stripping rate is highest with the solution of NaOH, and the stripping rate over 90% with the solution of Na₂CO₃ or NaHCO₃. When the loaded-extractant contain impurities, a black precipitation of floc generate in the stripping solution of Na₂CO₃ or NaOH, then the stripping rate decreasing. Stripping with the solution of NaHCO₃ does not generate precipitation and have a good stripping effect. Under the optimum process conditions as stripping with the saturated solution of NaHCO₃, pH value is of 8-9, the stripping rate is about 65%.The precipitation rate of vanadium increases with amount of NH₄Cl. It is influenced by the amount of NH₄Cl most. The precipitation rate of vanadium is above 99.7% when the amount of NH₄Cl equal to 2.5 times of vanadium.The spent petrochemical catalysts content about 10% vanadium and the merits of Mo and Ni. With the process that is oil removal-spontaneity oxidation-hydrothermal process leaching vanadium and molybdenum- leaching alumina with caustic soda by hydrothermal process, the infection factors of the leaching rate, like leaching reagent, temperature, time, and particle size, have been studied. The experiments show that the leaching effect of sodium carbonate excelled the one of caustic soda The leaching rates of vanadium and molybdenum which are leached from dead catalyst with sodium carbonate increase with the temperature and the time, decrease with the particle size. And the temperature influence on the leaching rate most. The concentration of sodium carbonate obvious influence theleaching rate of vanadium, but nearly does not have the influence to the leaching rate of molybdenum. The leaching rate of vanadium and molybdenum can reach to 90% as the concentration of sodium carbonate is at 125g/L, the concentration of sodium nitrite is at 62.5g/L, the particle size of dead catalyst is 0.12mm, the temperature is 150°C, the duration of the leaching is 1 hour by hydrothermal process.The theory and process of recovering vanadium from spent sulphuric acid catalysts and spent petrochemical catalysts are studied. According to the experiments, the basic rule of process is realized, the optimum process parameters are determined and the technology of vanadium metallurgy is enriched.