Magnetic separation concentration method

Abstract

The invention involves a method of select enriched magnetic powder which includes pre-drying, grinding and magnetic separation. A, sending wet magnetic powder which particle size is 0-30mm and TFe<=40% into drying equipment to pre-drying, temperature should be controlled below 950 degree C, the initial water content should decrease from <=20% to <=5% through pre-drying;B, cooling the pre-dried magnetic powder in step A until the temperature below 100 degree C, sending it into a mill equipments to grinding until the size <= 6mm, while using waste heat of magnetic powder and the friction heat when grinding further drying water content <=2%; C, using magnet separator to magnetic select and enrich the magnetic powder treated in step B, then preparing Fe fine powder which TFe>=55%, clean granule steel which TFe>=90% and non-magnetic tailings powder. The invention can separate slag and steel completely and increase magnetic slag TFe significantly; The production process do not discharge wastewater and waste slag, and no dust emissions, it achieves completely effective use of steel slag resources and clean production of steel slag processing and treatment.

Description

【Technical field】 [0001] The invention relates to a method for resource comprehensive utilization of metallurgical steel slag, in particular to a method for enriching magnetic separation powder for resource comprehensive utilization of steel slag. 【Background technique】 [0002] Glossary explanation: TFe refers to the grade of iron, that is, the weight percentage content of iron. [0003] Magnetic separation powder refers to the magnetic steel slag with TFe≤40% and particle size≤30mm obtained from metallurgical steel slag after stewing, crushing, magnetic separation and classification. [0004] With the continuous expansion of my country's steel production, the output of steel slag is also increasing. The development and utilization of steel slag resources is an important measure to realize the comprehensive utilization of metallurgical steel slag resources. It is also in line with the national industrial policies on comprehensive environmental management and comprehensive u...

AI Technical Summary

Problems solved by technology

[0006] As we all know, the mineral composition of non-magnetic steel slag mainly consists of calcium silicate (CaO·SiO 2 ), dicalcium silicate (2CaO SiO 2 ), tricalcium silicate (3CaO SiO 2 ), iron silicate (2Fe·SiO 2 ), manganese silicate (MnO SiO 2 ), calcium ferrite (CaO Fe 2 o 3 ), dicalcium ferrite (2CaO Fe 2 o 3 ), calcium olivine (CaO FeO SiO 2 ), tricalcium phosphate (3CaO·P 2 o 5 ), calcium fluoride eutectic (CaO CrF 2 ), etc. Steel slag is stewed by water spraying, multi-stage screening and magnetic separation to obtain TFe≤40% magnetic separation powder, the water content is generally below 20%, and the steel grain surface is covered with thicker slag powder. Due to the surface tension of water, the magnetic slag and the non-magnetic slag adhere to each other; before the non-magnetic tailings are produced into new energy-saving and environmentally friendly building materials, the metal iron in them must be removed first, and then dried until the water content is lower than 2%. During wet grinding, not only the metal iron cannot be completely removed, but the chemical activity of the steel slag is greatly reduced, and its initial moisture content is above 30%, which makes the drying energy consumption too high and the difficulty of recycling increases.

[0007] In order to further improve the grade of magnetic separation powder, most domestic iron and steel plants adopt wet ball mill washing and wet magnetic separation enrichment process to further process the magnetic separation powder with a particle size of 0-30mm, but the disadvantages of this process are: 1. It is due to the high viscosity of the ore slurry in the process of magnetic separation and enrichment, so that the product iron concentrate powder TFe can not reach 55%, which makes the sintering ore blending more difficult and the dosage is also small; the second is that the broken small steel particles wrapped in the slag cannot be completely Recycling has caused a waste of resources; the third is that the metal iron content in the non-magnetic tailings exceeds 1%, and its water content is higher than 30%. After the tailings react with water, the tailings lose their chemical activity, making them used as cement. The difficulty of mixing materials and deep processing into concrete admixtures increases, and the performance decreases; Fourth, the discharge of ore washing water causes environmental pollution and waste of water resources and mineral resources

Images