The conventional four - step reaction was simplified to one step
The technology for simultaneous separation of aluminum-vanadium from chromic salt production, jointly completed by the process engineering institute of the Chinese academy of sciences and sichuan yinhe chemical co., LTD., was approved last week in Beijing by the China petroleum and chemical industry association.The appraisal committee agreed that: this technical index is advanced and strong in application, which is conducive to promoting the chromium salt industry to reduce cost, increase efficiency and clean production, and reach the international leading level, and suggested to further accelerate the promotion and application.
Compared with the current industrial step-by-step method of removing vanadium and calcium by neutralizing and removing aluminum and adding calcium and removing vanadium, this technology can achieve synchronous removal of aluminum and vanadium. In terms of the process, the four-step removal reaction that has been used by domestic and foreign industries for nearly 50 years is simplified into a one-step reaction, avoiding the occurrence of highly carcinogenic CaCrO4 side reaction in the process of removing vanadium.From the production process, the technology completes the vanadium removal in the process of neutralization and removal of aluminum, avoiding the following processes of adding calcium to remove vanadium, adding sodium to remove calcium and aging.
Ma shunyou, deputy general manager and chief technology innovation officer of yinhe chemical, told China chemical industry daily that the technology has been applied and demonstrated in the production line of 70,000 tons of chromium salt per year. The production cost has been reduced by 16.44 million yuan per year, the source of waste residue containing chromium has been reduced by 7,000 tons per year, and the annual emission of chromium residue has been reduced by more than 10%.
Ma Shunyou, according to the technology research and development unit process engineering in national natural science fund support, the chromate Na2CrO4 - NaAlO2 - NaVO3 - H2O alkaline solution system and the process of neutralization - H2SO4, through to the interface structure design and regulatory synthesis large specific surface of mesoporous structure gamma AlOOH regularity, and the selective adsorption of anionic coordination polymer solution control mechanism of key scientific problems such as research, to realize aluminium vanadium synchronous separation, replace the traditional multi-step separation method, for the establishment of the technical system of scientific and technological achievements laid a theoretical foundation.
In order to realize the industrial application of this technology, the institute cooperated with galaxy chemical research and development team to conduct the industrial application research of the new technology of synchronous separation of aluminum and vanadium in the chromium salt production process.Starting from the optimization of roasting process of chromite, they solved the stability problem of impurities such as aluminum in alkaline leaching solution by stabilizing the reaction transformation of aluminum and other components of chromite, and solved the removal problem of aluminum and vanadium impurities by strengthening the neutralization reaction process.Finally, they not only realized the efficient synchronous removal of aluminum and vanadium impurities, but also avoided the generation of chrome-containing calcium vanadium slag and the source reduction of chrome-containing aluminum sludge by 22.9%.In addition, the technology also enriched aluminum and vanadium from chromium salt leaching solution, which laid a foundation for the further high value utilization of valuable aluminum and vanadium resources.
As a typical green applicable technology, this technology is of universal significance to the cost reduction and efficiency increase of the chromium salt industry and the source emission reduction of chromium slag. It can reduce the production cost of the product ton of chromium salt calcine-free roasting production technology by 3%~5%, and the product emission of chromium slag ton is reduced from 0.8~1 ton to 0.5~0.7 ton, a reduction of more than 10%.At the same time, the technology also paves the way for the high value utilization of chromite vanadium resources. In the future, the waste residue containing chromium can be further reduced by 30%, and high value-added aluminum and vanadium products can be produced, which is conducive to the cost reduction, efficiency improvement and clean production of chromite salt industry.
Technological innovation
● a new method was established to rapidly neutralize hydroxyl aluminum by regulating the colloidal precipitation and dissolution equilibrium of aluminum hydroxide during the neutralization and hydrolysis of sodium aluminate solution. For the first time, the synchronous and efficient removal of vanadium during the neutralization and removal of aluminum in sodium aluminate solution was realized.
● developed a new technology and special equipment for aluminum vanadium continuous synchronous removal in chromium salt production.The removal rate of aluminum and vanadium was more than 99% and 97% respectively.
● a new technology of returning slag weathering preheating water quenching and strengthening aluminum extraction is developed, which greatly improves the transformation stability of aluminum in chromite reaction process and ensures the stability of components in sodium chromate leaching solution.