Aluminum industrial red mud-based dephosphorizing agent for converter steelmaking and preparation method thereof

Abstract

The invention discloses an aluminum industrial red mud-based dephosphorizing agent for converter steelmaking and a preparation method thereof, belonging to the field of converter steelmaking. The dephosphorizing agent is mainly prepared from the following raw materials by mass percent: 50-70% of dried red mud, 5-15% of lime, 15-30% of iron ore concentrate or iron sheet ball, 2-10% of light roasting dolomite, and 0.5% of binding agent. The dephosphorizing agent is prepared by the following steps of crushing the raw materials, mixing uniformly, pressing into chunks, roasting for 2-4 hours at 300-500 DEG C, cooling down, and then crushing into the dephosphorizing agent with grain size of 15-30mm. The dephosphorizing agent is added in dephosphorizing step in steelmaking by the converter, can be used for processing molten iron with middle or low content of phosphorus, and can remove more than 90% of phosphorus. By utilizing large amount of CaO and Fe2O3 in the red mud, the dephosphorizing agent not only has good dephosphorizing effect, but also solves the problem of red mud pollution, thus recycling the red mud and lowering the cost for steelmaking.

Description

technical field [0001] The invention relates to the field of converter steelmaking, in particular to a dephosphorization agent for converter steelmaking synthesized from aluminum industry red mud as the basic raw material, supplemented with lime, iron concentrate or iron balls, lightly burned dolomite and a small amount of binder, and its preparation method. Background technique [0002] Red mud is a kind of solid waste in the production process of the aluminum industry. About 1.0-2.0 tons of red mud is produced for every ton of alumina smelted. Based on the current production capacity, the annual output of red mud in the world exceeds 70 million tons. The red mud produced is also more than 30 million tons. Among them, the red mud smelted by the most advanced combined method also contains 43.7-46.8% CaO and 20.0-25% SiO 2 , 5.4~7.5% Al 2 o 3 , 6.1~7.5% Fe 2 o 3 , and a small amount of Na 2 O, K 2 O and TiO 2 Wait. If not utilized, these resources will be wasted, an...

AI Technical Summary

Problems solved by technology

Because red mud contains certain valuable metals and non-metallic elements, such as aluminum oxide, iron oxide, silicon oxide, calcium oxide, zinc oxide, etc. in different proportions, in addition, it also contains trace elements Ti, Ni, Cd, K, Pb , As, etc., is a precious and abundant secondary resource, so it is of great significance to the recovery of valuable metals and rare rare earth elements in red mud, but the general cost is high, the process is complicated, and it is difficult to promote in China

[0004] At present, the dephosphorization agent used in the converter steelmaking process is mainly composed of lime (CaO), iron oxide scale (Fe 2 o 3 ) and a small amount of light-burned dolomite (mainly CaO and MgO). These raw materials need to be purchased from outside except for a small amount of iron oxide scale that can be produced by the steel plant itself, which is one of the important costs in the steelmaking process. Moreover, due to the high melting point of lime, a small amount of fluorite (CaF 2 ) as a flux to reduce the melting point of slag, but because fluorite contains fluorine, it will cause certain environmental pollution and has been banned from use. Therefore, how to reduce the melting point of dephosphorization agent is also an important issue