Method for extracting iron through reducing roasting red mud in bayer process

Abstract

The invention discloses a method for extracting iron through reducing roasting a red mud in a bayer process. A chloride-containing compound used as a segregation agent, a sodium-containing compound used as an accelerant, an iron-containing compound used as a nucleating agent, a calcium-containing compound used as a sulphur-fixing agent, and a carbonaceous reducing agent are added into the red mud;and according to the mass ratio of the red mud, the adding dosage of the chloride-containing compound is 3 to 10 percent by weight, the adding dosage of the sodium-containing compound is 5 to 15 percent, the adding dosage of the iron-containing compound is 3 to 8 percent, the adding dosage of the calcium-containing compound is 5 to 12 percent, and the adding dosage of the carbonaceous reducing agent is 5 to 15 percent. According to the method provided by the invention, a method for reducing roasting the red mud is adopted, so that iron in the red mud is reduced into low-price magnetic matterswhich are gathered together under the action of a nucleating agent so as to form large-grained crystal grains and be sorted through weak magnetism. According to the method, the metal conversion rateand a segregation effect in red mud reducing roasting can be remarkably improved, so that an effect on improving the iron recovery rate or the grade is achieved.

Description

technical field [0001] The invention relates to the fields of industrial waste recycling and environmental protection, in particular to a method for iron extraction from Bayer process red mud reduction roasting. Background technique [0002] Red mud is a strong alkaline solid waste discharged during the alumina production process. It is called red mud because of its high content of iron oxide (generally between 10% and 30%) and a red color similar to red soil. my country is the world's largest producer and consumer of alumina, and its alumina output accounts for about 35%-40% of the world. At present, there are three main methods of alumina production: Bayer method, sintering method and combined method. The Bayer method produces 1-1.5 tons of red mud for every 1 ton of alumina produced. For the sintering method and combined method, 1.5-2.5 tons of red mud is discharged for every 1 ton of alumina produced. As of 2015, the global stockpile of red mud has exceeded 3.5 billion...

AI Technical Summary

Problems solved by technology

[0005] Because the iron in red mud is very small, most of it will be wrapped by other minerals, especially mica. If it is directly reduced and roasted, there will be two obvious problems: first, iron is made of red mud. It is difficult to dissociate and reduce because it is wrapped by rock minerals or other minerals; then, because the iron in red mud is too small, even if it is reduced to a low-valence magnetic oxide during roasting, it will not be recovered during the magnetic separation process. Cannot be separated by magnetic separator

Images