Fluxing dolomite from Dolomit, town of Dankov, Lipetsk Oblast Fused flux from NLMK Lipetsk Fluxing dolomite is a crushed raw dolomite from the Europe's biggest dolomite deposit — the Dankovskoye deposit. Dolomite is the cheapest source of magnesium oxide that is used as flux in the iron and steel industry. Fluxing dolomite is used in the sintering and basic oxygen steelmaking operations as a raw material additive to molten metal. Fused flux is an alloy of metal salts and oxides that is produced by the fusing-together of charge ingredients in an electric arc furnace followed by the granulation of melt. Fused flux is used in automatic and semiautomatic arc welding and weld overlays, electroslag remelting of steel and alloys. Based on the silicon dioxide (SiO2), magnesium oxide (MgO), calcium oxide (CaO) and sesquioxide (R2O3) content and grain distribution, raw dolomite is classified into various grades. Chemical composition The numbers indicate the low of the rated raw dolomite grain size in mm. Flux grade SiO2,% MnO, % CaO, % MgO, % Al2O3, % K2O Na2O, % CaF2, % Fe2O3, %, max S, %, max P, %, max An-348f 36–44 26–38 <6.5 5–10 <6 — 4–8 2 0.15 0.12 DF-20 An-348fm 36–44 26–38 <6.5 5–7.5 <5 — 3.5–6 2 0.15 0.12 20–90 mm An-60f 36–46.5 26–41 3–11 0.5–3 <5 — 5–8 1.5 0.15 0.15 An-20cf 19–24 <0.5 3–9 9–13 27–32 1-3 25–33 1.6 0.08 0.15 Anf-29f 11–19 — 24–30 2–9 13–19 — 27–45 0.5 — — Anf-28f 20–25 — 24–32 <9 <5 — 28–49 1.5 — — An-295f <6 — 26–31 <6 49–56 — 11–20 — — — Grades and fractional composition of raw dolomite Grade DK-3 Fraction 3–15 mm Range of application For the manufacture of limestonepericlase brick DO-20 20–50 m DO-50 DM-0 50–90 mm DF-10 0–5 mm For basic oxygen steelmaking 10–40 mm For sintering operations Chemical composition Grade DK-3 DO-20 DO-50 The moisture content of flux must not exceed 0.1%. MgO content, mass %, minimum 18.5 17.0 17.0 Flux is packed into paper bags as per GOST 2226-75, metal drums as per GOST 4761-91 or other containers that preserve it while it is in transit. With the end user’s consent, flux may be shipped in open containers or heaped into railcars. CaO content, mass %, maximum 33.0 — — SiO2 content, mass %, maximum 1.6 4.0 4.0 R2O3 content, mass %, maximum 1.0 2.0 2.0 Grade DM-0 DF-10 DF-20 Average monthly MgO content, mass %, minimum 15 17 17 Rejection limit on the MgO content of some batches, %, maximum 14 16 16 Average monthly insoluble precipitate content, mass %, maximum 6 5 5 Fluxing limestone is used as flux at steelworks and lime-making plants. Limestone is used as an additive to blast-furnace charge, in pellets and sinter, and is also used in the ferroalloys and steelmaking operations. Rejection limit on the insoluble precipitate content of some batches, %, minimum 7 6 6 Qualities Limestone for fluxing from NLMK Ural, town of Revda, Sverdlovsk Oblast Fraction CaO+MgO, %, minimum Lumps the size of “above an upper limit”, %, maximum content Sand, clay and other impurities content 0–40 mm 50 10 — It is heaped into trucks or gondola cars and shipped out by truck and by rail respectively. Shipment from Dankov railway station. The limestone's qualities meet the quality requirements of STO 55791017-011-2017 “Limestone for fluxing”. Limestone is transported in railcars or trucks. Shipment from Revda railway station. 76 BULK PRODUCTS 77