Preparation Of SiO₂ Functional Mesoporous Materials From Molybdenum Tailings

Mineral resources are a kind of non-renewable resources. With the excessive exploitation of human being, reserves reducing speed is very high. The research development and comprehensive utilization of lean ore and tailings have vital significance to the effective utilization and sustaninable development of state resources. This article aims to prepare SiO2 aerogel and white carbon black mesoporous functional materials using the molybdenum tailings residue after molybdenum extracted as silica source on the basis of molybdenum element enrichment and extracting.Using molybdenum tailings as raw materials, the extraction and utilization of Mo element and Si elements were integrated into a process route. The influence of different process conditions on the molybdenum element enrichment and extraction were discussed.The results show that the molybdenum extraction amount could attain to largest value under the following process conditions: the mixture being calcined at 600 ℃ for 3h after ball milling of molybdenum tailings with sodium carbonate weight ratio of 10:9, then being reacted with ammonia with liquid/solid weight ratio 8:1 at 60 ℃ for 4 h, and extracting the molybdenum using 5 mol/L nitric acid from the ammonia immersion liquid. The final extracting rate of molybdenum could attain to 87%.The influences of different process conditions on the leaching amount of Si were discussed. The results indicate that maximum Si leaching amount could be achieved under the conditions of reaction at 100 ℃ for 6h with sodium hydroxide solution concentration 4 mol/L and liquid/solid weight ratio 5:1.Using the Si leaching liquid(water glass) as Si source, the preparation of SiO2 aerogel via ambient pressure drying was studied. The crystal phase, microstructure and chemical groups of the as-prepared aerogels were analyzed. The results indicate that the prepared SiO2 aerogels present a smooth surface with porous Si network with the specific surface area586.99 m2?g-1, average pore size 8.59 nm and pore volume 2.52 m2/g, The optimum properties of aerogels in aged 12 h.Mesoporous white carbon black materials were prepared using Si leaching liquid(water glass) as Si source. The effects of different catalyst concentration on preparation of whitecarbon black were investigated. The specific surface area, pore size and particle morphology were characterized by N2 adsorption-desorption BET and transmission electron microscopy method. The results indicate that the biggest white carbon black production rate of more than 95% attained with 1 mol/L HCl, and the average particle size of white carbon black was less than 200 nm with specific surface area 203~254 m2/g and pore volume 0.23~0.81cm3/g, respectively.