Recycling Of Amorphous Silica Using Zr-Containing Silica Residue And Comprehensive Experimental Research On Zirconium-rich Products

Zr-containing silica residue is solid gelatinous waste discharged during industrial process of zirconium oxychloride from zirconite fllowed by the acquisition of ZrOCl2 by solid-liquid separation. Recycling of amorphous silica and zirconium-rich products from Zr-contaning silica residue as resource is very meaningful for reducing solid waste and environmental pollution.In this experiment, preparation technology of amourphous silica and zirconnium-rich products using Henan Zr-containing silica residue as raw materials was researched. Influencing factors of recycling technology were survyed and optimized. Meanwhile, the property of products was tested and characterized.The technology of amorphous silica recycling from Zr-containing silica residue under laboratory condition was researched. The results of showded that the depolymerization of amorphous silica from Zr component can be realized using a process flow that thrashing, pulping, grinding, washing, solid-liquid separation and regulation of pH, and separation base on depolymerization must be realized as well. Amorphous silica was finely purified. Optimal process condition were obtained: solid content 4%, ball/materials ratio 10:1, grinding time 15min, filtering washing for three times, the pH of the slurry need be controlled nearby 7, wich regulated by CaCO3 solution. The grade of SiO2 of amorphous silcia is 95.5%, which obtained by wate recovey.The technology of amorphous silica recycling from Zr-containing silica residue under .pilot-scale experiment condition was researched. Amorphous silica was gathering and purified using a process flow that powerful thrashing, pulping, grinding by stirring mill, washing by stirring, solid-liquid separation etc. The grade of SiO2 of amorphous silica is 91.7%, which obtained by recovery.Simultaneously,the technology of zirconium component using washing figtrate following the separation of Zr- containing silica residue as raw materials was studied. The process flow is washing figtrate, adjusting pH by adding CaCO3 solution, aging, olid-liquid separation. The grade of SiO2 of the product recycled by optimizing technology was 58.5%. Zr-rich product was mainly consist of amorphous and zirconium silicate facies. The optimum pH was confirmed at 5.87, and temperature made little sense to the recycling of zirconium-rich product.The chemical propertities of the aourphous slica was tested, characterized and evaluated. The grade of aourphous silica by laboratory experiment is 95.5%, the specific surface areas was 494.3m2/g, grain size dittributed in 2~3μm, pore diameter is at the range of mesopores, wich size is 5~5nm. The grade of SiO2 by pilot-scale experiment was 91.7%. The two aourphous silica both meet the standard ISO5 794-1 and HG/T 3061.The mechanism of recycling of aourphous silica from Zr-containing silica residue was elaboreted, mainly from three aspects of recycling process dissociation, water seperation, adjustment of pH. As well as, processing feasibility and environmental impact were analysised and evaluated.