Perfection of a technology of processing and utilization of fine fractions of dump slag

Abstract

Processing of old dumps slag at crushing-sorting facilities results in a large yield of slag fine fractions – screening. Because of high content of metal inclusions and powder-like fraction in the screening, this product often becomes unclaimed and is returned to dump. Magnetic separation can increase the consumer properties of the slag screening, but it is only magnetic product that is returned to the processing while the mineral part is left in the dump. Basic characteristics of 0–10 mm fraction quoted. It was determined by laboratory study, that after extraction of ferromagnetic inclusions, the true screening density decreased by 17.5% and bulk density – by 3.1%. The powder-like inclusions remain in the screening, that does not allow to consider the material as a filler for concrete and macadam-sand mixture for road-building. To recycle the magnetic product, extracted out of the screening, decreasing of slagging is needed, as well as systematic evaluation of sulphury inclusion content in it. It was proposed to divide the slag screening for macadam and sand fractions after maximum possible removal magnetic inclusions and powder-like inclusions. It will allow to return into the utilization a part of iron previously lost with the fraction 0–10 mm and to obtain an iron concentrate for sintering. The remained tails in the form of macadam of 5–10 mm fraction, sand 0–5 mm and meliorant with decreased iron content can be used in construction industry and agriculture. By field tests it was determined, that adding meliorants, which contain a grinded screening with oxides of magnesium, phosphor and microelements, into soil, results in increasing crop capacity of vegetables by 30% at test areas.