Process for high-temperature roasting high-sulfur high-arsenic limonite in rotary kiln

Abstract

The invention relates to a process for high-temperature roasting high-sulfur high-arsenic limonite in a rotary kiln. The process mainly controls the temperature of a preheating section and the temperature of a burning zone of the rotary kiln to reduce weakly magnetic or nonmagnetic limonite to ferromagnetic magnetite and remove most of sulfur and arsenic so as to obtain finished products which can be directly used as blast furnace ironmaking raw materials. By using the high-and-low temperature combined method to remove sulfur and arsenic, the invention ensures that the removal rate of sulfur and arsenic is more than 96%.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy, in particular to a roasting process for high-sulfur and high-arsenic limonite raw materials. Background technique [0002] Limonite is one of the main iron minerals, which is a brown natural multi-mineral mixture mainly composed of hydrous iron oxide. But its iron content is not high, some are only 40-50% (weight), and there are many impurities such as sulfur, phosphorus, arsenic, especially the content of sulfur and arsenic reaches 2% (weight), so the use of The physical method of beneficiation is more difficult. Generally, the roasting process is adopted for beneficiation. [0003] The traditional limonite roasting process uses rotary kiln reduction magnetization roasting, and the existing defects are: [0004] First, because the temperature of the firing zone in the rotary kiln is controlled at about 850°C, the product after roasting contains a lot of impurities due to the low react...

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Problems solved by technology

[0004] First, because the temperature of the firing zone in the rotary kiln is controlled at about 850°C, the product after roasting contains a lot of impurities due to the low reaction temperature, and the solid anthracite used as a reducing agent does not react sufficiently and remains in the Among the products, the product grade is reduced, and the finished products obtained by this method must be magnetically separated before they can be used as raw materials for blast furnace ironmaking

[0005] The second is that although in theory the removal of sulfur depends on the decomposition and oxidation of sulfur-containing substances at high temperatures (above 500°C) to become sulfur vapor or sulfur-containing oxides; the removal of arsenic is mainly through arsenic-containing ores at high temperatures (about 600°C ), and oxidized or reduced to arsenic trioxide and discharged with the tail gas, but in the actual production process, at the above theoretical temperature, the removal rate of arsenic is extremely low, only about 10%

[0006] The third is: it is easy to form rings in the kiln, the production cycle is short, and the efficiency is low

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