Comprehensive recovery of various useful minerals in iron tailings - Maanshan Nanshan Iron Mine and Baotou Iron Mine

First, Nanshan Iron iron ore

Iron metal in Nanshan hydrothermal deposits, complex natural type of ore, various types of minerals with different degrees of apatite, pyrite. The production capacity of the Nanshan Iron Mine's concave mountain plant is 5 million tons of raw ore, and the annual tailings discharge is 2.9 million m ³ . The average content of phosphorus and sulfur in the tailings is relatively high. The plant has established a phosphorus plant with flotation process. Recovery of sulfur and phosphorus resources in tailings. The pulp preparation process and the flotation process are shown in Fig. 1 and Fig. 2 respectively, wherein the phosphorus selection process is a coarse and two fine sweep, the phosphorus content of the obtained phosphorus concentrate is 14% to 15%; the sulfur selection process is a coarse two. Fine, the sulfur content of the obtained sulfur concentrate is 33% to 34%. Each year, 300,000 tons of phosphate concentrate and 90,000 tons of sulfur concentrate can be recovered from the tailings, which is equivalent to the concentrate production of a medium-sized phosphorus and sulfur plant.

Figure 1 slurry preparation process flow chart

Figure 2 selection process flow chart

2. Baotou Iron Mine

Baotou iron ore is the world's rare large multi-metal symbiotic deposits, rich in valuable ingredients iron, rare earth, niobium, fluorite, rare earth reserves are very rich. Baotou Steel beneficiation plant since the production recovered mainly iron ore mineral, followed by the recovery of part of the rare earth minerals, most rare earth minerals as tailings discharged into the tailings dam. In order to strengthen the recovery of rare earth, Baotou Steel Rare Earth Third Plant used the existing technology, equipment and personnel to set up a new beneficiation workshop in 1982 and began to recover the rare earth concentrate from the total tailings chute of Baotou Steel Concentrator. In the past ten years, the production process has been continuously improved, the rare earth concentrate selection index has been greatly improved, the production cost has been reduced, the product types have been increased, and the products can be flexibly produced according to market demand. The rare earth concentrate produced can not only meet the requirements. The factory needs to provide some commercial concentrates to the market and obtain significant economic benefits.

Steel processing plant tailings total rare earth minerals mainly bastnasite and monazite, the gangue minerals are iron minerals, fluorite, barite, apatite, biotite, quartz, feldspar and carbonate Wait. The rare earth content is 4% to 7%, the pulp concentration is 2% to 5%, the particle size is -0.074mm, 50% to 70%, and the rare earth monomer is 50% to 70%. It contains a large amount of slime, residual medicine and other incorporation. The main components of impurities are shown in Table 1.

Table 1 Selected raw materials and their ingredients (%)

After the improvement of the process, the selected workshop uses the mixed flotation and separation flotation production process (see Figure 3) to recover the rare earth concentrate. The slurry extracted from the tailings tank is concentrated and classified, and then enters the mixed flotation sorting operation. Oxide paraffin soap as a collector , sodium carbonate, water glass as a regulator and inhibitor, flotation in the basic pH of pH 9 ~ 10, so that fluorite, barite, apatite and other calcium, The strontium minerals and rare earth minerals are separated from the iron silicate minerals. After a coarse multi-sweep operation, the fluorite and rare earth mixed foam products are obtained; the mixed foam is degreased and dehydrated and then enters the rare earth rough selection operation, and the rare earth is coarsely selected to C ₅ ～C. _6- alkyl hydroxamic acid is used as a collector for rare earth minerals, sodium carbonate is a pH adjuster, sodium fluorosilicate is an activator of rare earth minerals and as an inhibitor of certain gangue minerals, flotation at pH 9-9.5 Rare earth minerals, rare earth rough-choice foams are added directly to the selected agents after they are added to the above-mentioned agents. The production operation is stable, the process structure is simple and compact, the adaptability is strong, the sorting effect is good, the selection index is high, and the economic benefit is remarkable. In the case of poor material selection, the qualified rare earth concentrate containing REO ≥ 50% can still be obtained, so that the rare earth concentrate yield is increased by 2% to 3% on average, and the twisting rate is increased by 15% to 20%.

Figure 3 Principle process for recycling rare earth minerals