Obtaining of silicon dioxide from abrasive wastes

Abstract

In the production of abrasive materials from metallurgical slags, fine waste with a size of less than 40 microns is produced, which contains valuable components. Unlike slag, this waste does not need to be pulverized for processing, which greatly simplifies the process. However, without silica extraction, it is impractical to carry out waste treatment. The authors of the work considered the possibility of obtaining silicon dioxide from abrasive wastes of Rezh, Orsk and Kyshtym, containing up to 20,7 % of silicon, up to 31,7 % of iron and up to 0,7 % of the sum of nickel and copper. Sulfuric acid treatment of waste produced a solution containing magnesium and iron (II) sulfates and silicic acid. It was found that during processing of Orsk wastes the degree of components extraction is significantly lower in comparison with Rezh and Kyshtym wastes 24,5, 67,8 and 59,3, respectively. The obtained solution is used to produce silica powders by dehydrating it. The dried mixture is subjected to aqueous washing of metal sulfates. As a result, samples with high specific surface area in the range of 387,6 to 841,5 m2/g were obtained. The average pore size is 2,3–3 nm, which allows us to attribute these silicas to mesoporous silica. SiO2 content in the samples reaches up to 98 %. Samples of silicon dioxide from abrasive materials were compared with that obtained from metallurgical slag of Pechenganickel Combine and have similar parameters. The obtained insoluble leaching residue contains concentrate of non-ferrous metals and according to X-ray data it consists of calcium sulfate, so after separation of non-ferrous metals it can be used in construction industry.