Current state of steelmaking slag processing

Abstract

In the present work, the properties and composition of steelmaking slag are assessed by analysing existing processing methods, including desulfurisation and dephosphorisation. The atomic absorption and optical emission methods were used to study the chemical composition of slag samples, and metallographic analysis was used to study their microstructure. Major approaches to processing slags applied in Russia and abroad were studied. It was shown that steelmaking slags are neutralised and treated by various methods and subsequently applied in construction and road industries, while the obtained phosphorus-containing products are used in agriculture instead of superphosphate. In addition, these products reduce lime consumption and improve slag formation in steelmaking. The key factor hampering reusing electric steelmaking and converter slags for metal refining is shown to be the presence of phosphorus. The chemical composition of slag samples from the electric steelmaking production was analysed; the iron content amounted to 33.2 wt%, calcium – 19.15 wt%, phosphorus – 0.33 wt% and silicon – 5.39 wt%. Iron is present in the oxidised form (FeO, Fe2O3 and Fe3O4), silicon and calcium in the form of dicalcium silicate (2CaO ∙ SiO2 ), phosphorus in the form of calcium silicophosphate having complex composition – Ca2(SiO4)6(Ca3(PO4)2. Phosphorus is fed to the melting units with gangue minerals, agglomerate, ore and fluxes. When the slags are reused, phosphorus returns to the metal, thus contaminating the final product. Possible methods for extracting phosphorus from steelmaking slags include magnetic and electrostatic separation, gravity and flotation concentration, as well as hydrometallurgical processing.

Pyrometallurgical Technology for Extracting Iron and Zinc from Electric Arc Furnace Dust

“…Steel production occupies a leading position in the metallurgical sector worldwide [1][2][3][4][5]. The rapid growth of steel production on a global scale over the past 20-30 years has attracted the attention of experts to the increasingly harmful environmental impact of ferrous metallurgy enterprises [6][7][8], including the generation of hard-to-recycle humanmade waste [9][10][11][12].…”

The influence of automatic arc welding modes on the geometric parameters of the seam of butt joints made of low-carbon steel, made using experimental flux

“…При восстановлении железа из шлаков побочным продуктом становится агломерат оксидов, который можно рассматривать как флюсовую композицию для дуговой сварки/наплавки под слоем флюса, наполнителей порошковых проволок и покрытий сварочных штучных электродов [14]. Состав новой флюсовой композиции во многом определяется шлаковой системой, используемой электросталеплавильным предприятием для производства стали конкретной марки [15][16][17].…”

Electric steelmaking dust as a raw material for coagulant production

“…An effective solution to these problems can be the involvement of this waste in the resource circulation as a feed for the production of various materials, which is a prerequisite for low-waste and waste-free technologies. Such an approach to the disposal and processing of man-made industrial waste contributes to solving the issues of resource and energy saving, makes it possible to expand the range of manufactured products, increase the raw material base and its diversity [6,7]. In addition, the involvement in the production cycles of abandoned large-tonnage industrial waste will make it possible to release many hectares of land now under dumps and tailings and begin their reclamation and fertility recovery [8][9][10].…”