A silicon-carbon double-acidity composite pellet used in converter slag modification and its preparation method

Abstract

The invention discloses a silicon-carbon double-acidity composite pellet used in converter slag modification and a preparation method thereof. The composite pellet is composed of two inner and outer layers of materials with different acidities, and the inner layer material is: iron tailings 20%-50 %, blast furnace dust 45%‑75%, asphalt 2%‑6%, acidity M K =(SiO 2 +Al 2 o 3 ) / (CaO+MgO)=5~10, the outer material is: iron tailings 50%-70%, blast furnace dust 25%-45%, asphalt 2%-6%, acidity M K =(SiO 2 +Al 2 o 3 ) / (CaO+MgO)=10~20; after heating the inner and outer layer mixtures in the heating furnace to 350~500°C, use the inner and outer double-layer hoppers at 5~10t / cm 2 Under the high pressure, the composite pellets with a diameter of 10-60 mm are made by a double-roller ball pressing machine. Improve the utilization efficiency of iron tailings and blast furnace dust, reduce the proportion of low-temperature cold material, reduce the heat loss of molten slag modification, shorten the reduction time and smelting cycle, improve production efficiency, and ultimately reduce power consumption and production costs.

Description

technical field [0001] The invention belongs to the technical field of steel slag comprehensive treatment, in particular to a silicon-carbon double-acidity composite pellet used in the reforming of converter slag and a preparation method thereof. Background technique [0002] Converter slag is an industrial solid waste produced during the converter steelmaking process. For every ton of steel produced, 0.1-0.13 tons of steel slag is produced at a temperature of about 1350-1450°C. It also contains 10% to 30% total iron (TFe) and a large number of beneficial elements such as calcium, magnesium and silicon. At present, most iron and steel enterprises generally adopt simple magnetic separation. Except for a small part sold to cement plants, most of the remaining tailings are dumped, causing environmental pollution, land occupation and waste of resources. [0003] The pretreatment methods in the steel slag pretreatment part include: hot splashing method, hot stuffing method, dru...

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Problems solved by technology

[0004] The potential value of converter slag, a high-temperature-treated material, is far from being realized

The current research and practical application have proved that compared with blast furnace slag, RO phase, spinel phase, various iron-containing compounds, olivine phase, and metallic iron contained in converter slag are wear-resistant phases, which increase the processing efficiency of steel slag. cost, and the basicity of steel slag is high, there are more free calcium oxide and magnesium oxide in the slag, and the crystal grains of the gelling substance in the middle of the steel slag are dense, the reactivity is low, and the reaction time is long, which affects the stability of converter slag products , limiting the scope of use of converter slag

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