Lean magnet ore "stage grinding, single magnetic separation - fine screening and regrind" process

Anshan lean ore magnet is a high silica, low phosphorus sulfur-depleted magnetite, hematite, limonite content, and iron silicate, iron carbonate content higher, which is embedded in fine particle size and uneven, coarse ore A large amount of large particle gangue can achieve monomer dissociation during grinding. According to the nature of the poor magnetite ore in Anshan, it is considered to use the stage grinding and single magnetic separation process to treat the poor magnetite ore in Anshan. Compared with the magnetic-floating combined process, while providing qualified iron concentrates that meet the ironmaking requirements, the single magnetic separation process has the advantages of simple process, low operating cost, high iron recovery rate, reliable process, and the like, and uneven grain size. The embedded poor magnetite ore is treated by a single magnetic separation process, and magnetic separation equipment is often used in combination with screening equipment . Therefore, it is considered that “stage grinding, single magnetic separation-fine screening and regrinding process” is a suitable process for treating poor magnetite ore in Anshan area. The process is used to mix the ore of Dagushan ore in front of the mountain ore and the bowstone magnet. The ores were sorted separately and all had good selection criteria.

First, the nature of the ore

(1) The chemical composition of the ore

The multi-element analysis results of Dagushan ore, Yuqianshan ore and Gongchangling lean magnetite are shown in Table 1. The phase analysis results are shown in Table 2.

Table 1 Multi-element analysis results of raw ore (mass score) /%

Table 2 Raw mineral phase analysis results

It can be seen from Table 1 and Table 2 that the Dagushan ore, the anterior mountain ore and the Gongchangling lean magnetite in the Anshan area are all low-phosphorus ore with high silicon and low sulfur phosphorus, and the content of iron silicate and iron carbonate is higher. high.

(2) Mineral composition and structure of ore

Dagushan main types of ore, ore and Yanqianshan Gongchangling poor magnetite ore are: magnetite quartzite, amphibolite (green clay) magnet quartz rock, the illusion of hematite quartzite. The ore structure is dominated by a strip-like structure, and a wrinkle-like structure and a breccia structure are developed at the same time. The structure of the ore is mainly composed of a granular crystal structure, and at the same time, the structure and inclusion structure are developed.

(3) The inlay size of the ore

The Dagushan ore, the anterior mountain ore and the Gongchangling lean magnetite are all poor magnetite ore with unevenly embedded fine particles. The average particle size of the iron ore in front of the mountain ore is 44.95 μm, and the average particle size of the gangue mineral is 71.20 μm. The average grain size of iron minerals in the west of Dagushan Iron Mine is 38.54μm, the average grain size of gangue minerals is 53.52μm, the average grain size of iron ore in Mindong is 40.06μm, and the average grain size of gangue minerals is 67.74μm. The average particle size of the Gongchangling lean magnetite ore mineral is 49.74~69.65μm, and the average particle size of the gangue mineral is 69.55~100.20μm.

Second, the process of determining and selecting results

(1) Stage grinding, determination of single magnetic separation-fine screening regrind process

Because the Dagushan ore, the anterior mountain ore and the Gongchangling lean magnetite are all poor magnetite ore with uneven grain impregnation, and the gangue mineral inlay size is coarse, a large number of large gangue in coarse grinding The monomer dissociation can be achieved, so it is considered to adopt stage grinding, stage selection process to select, and to discard some low-grade tailings in advance, reducing the processing capacity of subsequent grinding and sorting operations. According to the results of the magnetic separation tube selection test, Dagushan ore, Yuqianshan ore and Gongchangling lean magnetite can be discarded at a grade of 10% to 65% when the grinding grain size is 0.075mm. The tailings rate is over 40%.

According to the phase analysis of Dagushan ore, Yuqianshan ore and Gongchangling lean magnetite, the ore is mainly composed of magnetic ore, and a small amount of iron silicate and iron carbonate. The content of red and limonite is very small. Due to the high content of iron silicate and iron carbonate, no matter which method is used, the grade of tailings will be high, while the content of red and limonite is very small. Therefore, a single magnetic separation process is considered. Moreover, compared with the magnetic-floating combined process, the full magnetic separation process has the advantages of simple process, low operating cost, high iron recovery rate and reliable process, while providing qualified iron concentrates that meet the requirements of ironmaking.

For the rare earth ore with uneven grain inlay, the magnetic separation equipment and the screening equipment are often used. The raw ore is thrown out of the qualified tailings under the condition of coarse grinding. The coarse concentrate is finely ground and then selected. Screening, re-selecting the product under the sieve to obtain high-grade concentrate, sifting the product on the sieve and then feeding it into the magnetic separation. The magnetic fine is fed into the fine sieve. After the re-grinding, the selection process of the magnetic sieve is overcome. The disadvantages of the post-magnetic process not only improve the sieving grade of the fine sieving, but also reduce the amount of sifting of the fine sieving, which can fully exert the effect of fine sieving and improve the sieving efficiency.

With the advent of high-efficiency magnetic separation equipment and high-efficiency screening equipment, this single magnetic separation fine-grain regrind process has become a cost-effective process for obtaining high-grade iron concentrates.

(2) Sorting results of three kinds of ores

The Dagushan ore, the anterior mountain ore and the Gongchangling lean magnetite are sorted by “stage grinding, single magnetic separation-fine screening and regrinding process”. The specific process flow is shown in Figure 1.

Figure 1 Stage grinding, single magnetic separation - fine screening and regrind process

The Dagushan ore and the mountain front ore are mixed into the “stage grinding, single magnetic separation-fine screening and regrind process” for sorting. The original ore grade is 29.73%, and the primary grinding size is 0.074mm. The fraction is 65%. secondary grinding grain size -0.074mm 87% level, and then grind size -0.074mm size fractions under 91% of the conditions, sorting index was: concentrate grade of 67.44%, 34.06% rate of fine mineral, metal recycling The rate is 77.26% and the tailings grade is 10.25%. Currently, the process has been in Dagushan beneficiation plant successfully applied, after the adoption process, Dagushan concentrator leather boutique level reached 67.5%, up 1 percentage point increase concentrate grade transformation of the former, but also improve the Production capacity. This provides a wealth of practical experience for the treatment of lean magnetite with “stage grinding, single magnetic separation – fine screening and regrind process”.

Gongchangling lean magnetite ore is selected by “stage grinding, single magnetic separation-fine screening and regrinding process”, with the original ore grade 31.23%, the primary grinding grain size-0.074mm grain size accounting for more than 60%, secondary grinding The particle size-0.074mm particle size accounted for more than 85%, and the regrind particle size-0.074mm particle size accounted for more than 85%. The selected index was: concentrate grade 67.80%, concentrate yield 37.04%, metal recovery rate 80.41. %, tailings grade 9.27%. At present, the Gongchangling First Selection Workshop has adopted this process to carry out production technical transformation. The comprehensive tailings grade after transformation can be reduced by 1% compared with the original magnetic-floating combined process, the metal recovery rate is improved, and the process is short. The process is simple, saving the cost of flotation of the medicament and reducing the production cost. The application of “stage grinding, single magnetic separation-fine screening and regrind process” in Gongchangling further illustrates that the process is a reasonable and advanced process for treating poor magnetite ore in Anshan.

Third, the process characteristics analysis

(1) Stage grinding, rough grinding and tailing. It adopts stage grinding and adapts to the uneven grain size of the original ore. The Dagushan ore, the anterior mountain ore and the Gongchangling lean magnetite are sorted by “stage grinding, single magnetic separation-fine screening and grinding process”. Under the condition of one grinding grain size-0.074mm grain size accounting for 60%-65%, using a magnetic separator to sort out low-grade tailings with a yield of about 40%, reducing subsequent grinding and The amount of processing for the sorting job. Abandoning the gangue and lean contiguous that have reached the monomer dissociation as early as possible to avoid circulation in the process, which is the preferred solution in the beneficiation process.

(2) Single magnetic separation and simple process. The single magnetic separation process is used to treat the poor magnetite ore in the Anshan area, adapting to the ore properties of the ore. Compared with the process of treating the lean magnet ore by the magnetic-floating combined process, the process is short and the process is simple. The iron loss in the tailings industry is very high. Less, the metal recovery rate is high, and the cost of flotation chemicals is saved, and the production cost is reduced.

(3) First magnetic sieve, fine sieve and grinding. The raw ore is thrown out of the qualified tailings under rough grinding conditions. After the coarse ore concentrate is selected by weak magnetic and fine grinding, the products on the sieve are mostly solid and non-dissociable inclusions, which must be reground to make fine particles embedded. The cloth and the iron minerals in the form of inclusions are fully dissociated in order to re-select the qualified concentrate. The regrind product adopts the pre-magnetic and post-screening selection process, which overcomes the disadvantages of large amount of minerals and large amount of re-grinding circulation after the first screening and magnetic process, which not only improves the screening quality of the fine screening, but also reduces the fine screening. The amount of ore and regrind can fully exert the effect of fine screening and improve the screening efficiency.

Fourth, the conclusion

(1) “stage grinding, single magnetic separation-fine screening and regrind process” adapts to the uneven grain size of poor magnetite ore in Anshan area, low content of harmful impurities such as sulfur and phosphorus in raw ore, and useful minerals are mainly magnetic minerals. Ore properties with very little red and limonite content.

(2) "stage grinding, single magnetic separation - fine screening and regrind process" has technological advancement and economic rationality. The ore mine throws qualified tailings under rough grinding conditions, which reduces the processing capacity of subsequent grinding and sorting operations; adopts a single magnetic separation process, which has the advantages of high metal recovery rate, simple process and low production cost; fine screening Grinding, the fine-grained inlay and the iron mineral in the form of inclusions are fully dissociated, and the magnetic sieve is firstly sieved, which not only improves the sieve quality of the fine sieve, but also reduces the amount of ore and regrind of the fine sieve. The role of fine sieving can be fully utilized to improve the screening efficiency.

(III) The use of “stage grinding, single magnetic separation-fine screening and re-grinding process” to treat Dagushan ore and Yuqianshan mixed ore and Gongchangling lean magnetite have achieved satisfactory results, which fully proves that the process is to deal with Anshan. Reasonable and advanced process flow of rare earth ore in the region.