Magnetite ore dressing plant practice - Angang Dagushan Concentrator

1 Overview

Dagushan concentrator 9km, located at the foot of Qianshan miles to the southeast of Anshan City, Liaoning Province, the plant has rail and road to the city and Anshan Iron and Steel plant, the main production of iron ore pellets and minerals, is the main raw material base of Anshan Iron and Steel one.

The main plant of the Dagushan pellet plant was established in 1954. There is a crushing operation area and two sorting operation areas. The crushing operation area adopts the medium-breaking pre-screening three-stage one-closed road crushing process; It adopts stage grinding, fine screening and re-grinding, and single magnetic separation sorting process; the three-selection working area adopts continuous grinding, fine screening and re-grinding, and single magnetic separation sorting process.

2 ore properties

A ore type

The Dagushan iron ore belongs to the Anshan-type iron ore. The ore body is a diorite porphyry traversing the middle part. The rock wall is divided into east and west parts. The east is called the east of the porphyry ore body, and the west is called the west of the porphyrite. The ore produced by them is referred to as the eastern ore. And the West Mine. Bin Dong unoxidized ore mine is, a magnet, amphibolite (green clay) magnetite quartzite; Bin western mining containing partial oxidation and oxide ores and a half, to the main magnet quartz rock, quartzite ore type magnet, magnet quartz amphibolite Rocks and magnets are like the pseudo-iron quartzite.

B chemical composition and mineral composition

The element for ore recovery in the ore is iron, the iron mineral is mainly magnetite, followed by limonite and hematite. The gangue mineral is quartz and a small amount of hornblende, chlorite, calcite and the like.

The chemical composition of the ore and the analysis results of the iron chemical phase are shown in Table 1 and Table 2.

Table 1 Chemical composition analysis results

Table 2 Phase analysis results

3 technical progress

Since 2004, the beneficiation process of the Dagushan Pellet Plant has carried out the upgrading of new iron and silicon-reducing processes and new equipment. After the transformation, it has formed an annual capacity of 9 million tons of raw ore. After that, the plant has undergone a series of technical transformations. Significant economic benefits.

(1) After the high-efficiency technical transformation of the φ53m thickener of the pellet plant, under the premise of meeting the capacity of processing 9 million tons of raw ore, less 5 φ53m large wells will be built, saving 10 million yuan, and improving the overflow quality of tailings thickener .

(2) In January 2005, the magnetic separation workshop of the concentrator was optimized to adjust the process and equipment structural parameters of the grinding and grading operations, and the ball mill was treated under the premise of maintaining stable operation of the first and second stages of grinding and grading operations. The amount increased from 128t/h to 132t/h, and the annual profit increased by 23.814 million yuan.

(3) The φ350mm cyclone unit of the ore dressing plant was transformed into two φ500mm cyclones. Under the condition of the same capacity, the overflow particle size and classification efficiency of the φ500mm cyclone were better than the φ350mm cyclone. More importantly, the application of φ500mm cyclone significantly reduces the clogging phenomenon of the grit chamber, improves the processing capacity of the mill, stabilizes the process index, and further reduces the grinding cost.

4 production process and process

Introduction to A process

The processing process of the Dagushan pellet plant is divided into two parts: the main plant and the beneficiation branch. The main plant is mainly composed of three parts: crushing, magnetic separation and three-selection. The process is as follows: The process of crushing is three sections, one closed circuit, and the middle break. Pre-screening process. The process used in the magnetic separation workshop is the stage grinding-単-magnetic separation-fine screening regrind process; the process adopted by the three-selection workshop is continuous grinding-single magnetic separation-fine screening regrind process; beneficiation branch The process adopted by the crushing system is a three-stage and one-closed process, and the sorting process uses a stage grinding-single magnetic separation-fine screening regrind process.

B broken, sieved

From 2004 to 2007, the beneficiation process of the Dagushan pellet plant was carried out to upgrade the new technology and new equipment for iron and silicon reduction. After the transformation, the ore processing plant processed 9 million tons of raw ore annually. In the crushing workshop, the original coarse crushing is retained, and the new main building is finely broken and sieved. The crushing main equipment adopts Swedish H series cone crusher, and the screening equipment adopts double-layer vibrating screen. The crushing feed size is 1000~0mm, and the product granularity is 12~0mm.

a main plant crushing and screening process The existing main plant crushing screen is divided into three sections and one closed circuit before the pre-sieving process. The coarse broken ore discharge product is sent to the medium for crushing and pre-screening, and after being sieved by the fixed rod sieve, the sieved material is broken into the medium-breaking machine for crushing, and the medium-breaking and discharging product is transported together with the pre-screened sieved object. The sieve compartment is sieved into the vibrating screen through the feeder, and the product is sieved into the fine broken mine bin. The belt feeder is used to crush the fine crusher and can be discharged into the open storage tank. Storage; finely broken ore products are transported to the screening room for screening. The sieved and screened products are respectively fed into the original ore bin of the magnetic separation workshop and the original ore bin of the three-choice workshop, and can also be stored in the powder ore bin. The main plant crushing and screening process is shown in Figure 1.

See Table 3 and Table 4 for technical parameters and indicators of the main plant crushing and screening equipment.

Figure 1 Main plant crushing and screening process flow chart

Table 3 Technical parameters and indicators of the main plant crushing equipment

Table 4 Technical parameters and indicators of the main plant

C grinding classification

In 2004, the magnetic separation operation area was carried out to upgrade the new technology and new equipment for iron and silicon reduction, and the factory was cancelled. First and second grinding use large-diameter grinding machine, the first and second grading adopt dynamic pressure feeding ore cyclone, which makes the raw ore processing volume and overflow product granularity greatly improved. Following the technological transformation in 2004, in October 2005, the three-selection process was continuously modified and improved, and the φ500mm x5 cyclone 2 group was replaced, and the product granularity was also improved.

See Table 5 for the technical indicators of grinding classification.

Table 5 Grinding classification technical indicators

D sorting process

a magnetic separation operation area process magnetic separation workshop adopts stage grinding-single magnetic separation-fine screening regrind process. The ore is fed into a ball mill , and a cyclone constitutes a closed circuit. The overflow enters a magnetic separator to remove the tailings. The concentrate is secondly graded by a secondary cyclone. The coarse-grained product enters the second-stage ball mill and discharges the ore. Return to the magnetic separator; the secondary graded fine-grain grade product is fed into the dewatering tank, the concentrate is fed into the secondary magnetic separator, the concentrate is fed into a vibrating screen, and the sieved product is fed into the dewatering tank for sorting. The sieved material is concentrated into a dehydration magnetic separator. The concentrated product is fed into a three-stage ball mill. The product is fed into a secondary dewatering tank. The concentrate is fed into a three-stage magnetic separator. The concentrate is fed into the second-stage vibrating screen. Screening, the sieved material enters the dehydration magnetic separator, the sieved product is fed into the three dewatering tanks for sorting, and the concentrate is fed into the filtration workshop. The process is shown in Figure 2.

Figure 2 Magnetic flow control area process flow chart

b Three-selection operation area Process The three-selection operation area is a two-stage continuous grinding--------------- The raw ore is fed into a ball mill, and the double-spiral classifier forms a closed-circuit grinding system. One stage of overflow is fed into the cyclone, and the second-stage ball mill forms a closed circuit. After the secondary overflow is fed into the magnetic separator, the tail is passed. The dewatering tank is tailed, the concentrate is fed into the secondary magnetic separator, the concentrate is fed into a vibrating screen, and the sieved product is fed into the dewatering tank for sorting. The sieve is fed to the dehydration magnetic separator for concentration, and the concentrated product is concentrated. It is sent to the ball mill for the third stage of grinding. The ore discharge product is fed into the secondary dewatering tank. The concentrate is given to the third magnetic separator for sorting. The concentrate is fed into the second section of the vibrating screen and the sieve is returned to the dehydration magnetic separator. After the first and second stage vibrating screens are combined and fed into the three dewatering tanks, the magnetic separator is given four times. The concentrate is fed into the four dewatering tanks for sorting. The concentrate is fed into the filtering workshop. As shown in Figure 3.

Figure 3 Three-selection work area process flow chart

The main equipment of the concentrator is shown in Tables 6 and 7.

Table 6 Magnetic separation work area equipment table

Table 7 Three-selection work area equipment table