Flotation machine maintenance and overhaul

First, flotation machine operation points and daily maintenance

(1) During the operation of the equipment, the temperature rise of the bearings and scraper bearings of the stirring mechanism shall be patrolled and shall not exceed 25 °C. The temperature rise of the motor bearings shall not exceed the allowable value.

(2) When there is abnormal noise in the rotor body, check the gap between the stator and the rotor, the spindle bearing, the transmission tape, and the rotor fixing parts to handle and replace the abnormal problem.

(3) Stator guide vanes and false bottom steady flow plates are easily worn under the scouring of high-speed pulp, and should be inspected frequently and replaced in time.

(4) The fastening bolts in the tank body are easy to loosen and fall off under the impact of high-speed pulp, which may cause the stator to sink. It should be inspected every shift and replaced in time.

(5) When the foaming rate of the foaming mechanism is lowered, check whether the oil resistant rubber sheet is damaged and adjust it in time.

(6) When the foaming mechanism vibrates or oscillates, check the drive shaft for cracks and whether the couplings are disconnected.

(7) Impeller inspection, when the impeller wear diameter exceeds, there are holes or cracks, it should be replaced in time.

(8) Lubrication of rotating parts

1The stirring mechanism and the speed reducer of the scraping mechanism change the oil every 3 months.

2 Stirring mechanism The spindle bearing is oiled once a month.

3 Oil-impregnated bearings of the scraping mechanism should be refueled once a day.

(9) The feeding amount and feed concentration should be stable, the dosing system should be reasonable, the air intake of the hollow shaft and the sleeve should be adjusted properly, the liquid level of the flotation tank should be adjusted, and the scraper should not be wiped.

(10) Stop feeding before stopping. When the parking time is too long, the mine valve should be opened to vent the coal slurry to avoid the sediment at the bottom of the tank and block the pipeline.

(11) Always check whether the liquid level automatic control device is reliable or not, and whether the liquid level reference value is appropriate.

Second, the common problem handling

When the flotation machine is in production or use, if the following phenomena occur, it can be adjusted according to the method described.

1 The amount of inflation drops. For the mechanical agitating flotation machine for coal, according to the different floatability of the flotation feed, the aeration volume of the flotation machine reaches 0.6~0.8m3/(m2·min), which can meet the process requirements. When the XJM-S flotation machine is obviously insufficiently inflated, the reason may be: the impeller stator group is seriously worn, the radial and axial clearance are too large; the stator circulation hole is blocked by debris; the hollow shaft aperture is too small; V-shaped The tape is slack and the impeller line speed does not meet the design requirements.

The adjustment measures are: adjust the axial clearance of the impeller. When the axial clearance cannot be adjusted or the radial clearance is too large, the impeller stator group should be replaced; the debris blocking the circulation hole of the stator should be cleaned or the large sleeve intake pipe or hollow shaft should be properly opened. Aperture; tighten or replace the V-belt.

2 The amount of suction increased. When the amount of suction is obviously insufficient, the reason may be that the lower gap between the suction port of the impeller and the inlet pipe is too large or different; the outlet of the impeller, especially the outlet of the lower wheel, is blocked; the V-shaped tape of the stirring mechanism is loose, the impeller line The speed decreases; the coal slurry circulation is too small; the hollow shaft aperture is too large.

The adjustment measures are: adjust the lower gap to 3-5mm; clean the debris at the exit of the lower umbrella wheel, especially at the outlet of the suction chamber; properly reduce the diameter of the hollow shaft; tighten or replace the V-shaped tape; clean the blockage of the circulation hole of the stator Sundries.

3 The stirring mechanism motor is hot. Under normal technical conditions, the motor power consumption of the XJM-S flotation machine should be no more than 35kW. When the motor power consumption obviously exceeds the rated power and heats up, the reason may be: the hollow shaft aperture is too small or even completely blocked; the coal slurry circulation volume in the flotation tank is too large; the motor is damp or the ventilation heat is blocked.

The adjustment measures are: reduce the circulation hole area (prioritize to reduce the circulation hole area of ​​the stator cylinder); appropriately increase the hollow shaft aperture; clean the motor cooling vent or overhaul the motor.

4 Flotation machine liquid level turning. There are many reasons for the floatation of the flotation machine, mainly: excessive inflation or uneven distribution; excessive circulation of coal slurry in the flotation tank; upstream of the flotation tank and the stator guide vane The end position does not correspond to the installation of the stirring mechanism is not vertical or the position is offset; the impeller is seriously unevenly worn; in some cases, due to excessive accumulation of coarse particles in the flotation, it cannot be discharged in time, and may also cause a liquid level similar to that of the porridge pot. Flower phenomenon.

The adjustment measures are as follows: appropriately reduce the amount of aeration and the amount of coal slurry circulation; properly close the sleeve circulation hole; align the water-receiving end of the groove bottom plate with the end position of the stator guide vane; and repair the flotation machine to make the stirring device vertical and make it The axis is at the center of the tank floor. If there are too many coarse particles in the flotation tank, measures should be taken to drain the coarse particles.

Maintenance and overhaul of flotation column

First, flotation column operation points and daily maintenance

(1) The collector is added to the mixing tank (pool), and the foaming agent enters the circulation pump suction pipe and is emulsified by the circulation pump.

(2) Under normal circumstances, all microbubble generators work at the same time. Do not close several adjacent microbubble generators at the same time, so as not to affect the bubble distribution and reduce the processing capacity and efficiency of the equipment.

(3) Pay attention to check the intake condition of each microbubble generator, and find that the fault is closed in time to repair the valve.

(4) Flush water should be used as little as possible or not.

(5) Form a system for regularly cleaning the media board.

(6) other operations with the general flotation machine.

Second, the characteristics of the flotation column

(1) In the mechanical agitating flotation machine, the collision and adhesion of coal particles and bubbles mainly occur in the high shear zone around the impeller blades, while the jet flotation machine mainly occurs in the throat and the umbrella disperser. Around the flotation column occurs in the cylinder from the feed port to the relatively large capture zone of the bubble generator.

(2) In other flotation machines, the direction of motion of the bubbles and the coal particles is generally straight or at right angles to each other, so the absolute motion speed is large and the relative velocity is small; while in the flotation column, the reverse flow, relative velocity Large, coal particles have a high probability of collision with bubbles.

(3) In other flotation machine tanks, the degree of turbulence of coal slurry movement is high, the probability of mechanical entrainment of mineral impurities is large; while the degree of turbulence in the flotation column is low, and it can be used to spray water in the middle and top of the foam layer. To strengthen the secondary enrichment.

(4) Since the flotation column is as high as 6-10 meters, the bubble generated by the bubble generator increases with the decrease of static pressure during the ascending cylinder, and with the strong bubble merger, it is necessary to use other floats. Select more foaming agents to reduce the surface tension of the water to maintain a certain diameter of the bubble.

(5) Compared with other flotation machines of the same volume, the flotation column has a much smaller aerated surface area, and its total aeration amount is much smaller than other flotation machines, so the unit processing capacity of the flotation column is in most cases. It is lower than other flotation machines, and the power consumption is higher than other flotation machines.

Third, the operating characteristics of the microbubble flotation column

(1) Adding spray water to the foam layer is one of the characteristics of the microbubble flotation column, which can control the clean coal ash and adjust the foam concentration. The normal amount of spray water is 60-90m3/h, which is about 55-85% of the feed amount. At this time, the clean coal ash can be controlled to 8.5% below. Increasing or decreasing the spray water will reduce the flotation clean coal ash or Increase.

(2) The feed amount of the flotation column directly affects the flotation process effect. The treatment volume of the microbubble flotation column with a diameter of 3 meters is less than 16t/h, and the ash content of the tail coal is reduced when the treatment volume is increased. The thicker the concentration and particle size composition of the feed, the smaller the upper limit of the effective sorting size of the flotation, and the lower the processing capacity.

(3) The foam layer thickness of the microbubble flotation column is generally 0.7-0.8 m, which can be controlled by controlling the liquid level. When the liquid level is high, the foam layer is thin, the clean coal ash is higher, and the liquid level is low, the flotation can be reduced. Clean coal ash, but at the same time the tail coal ash also decreased accordingly.

(4) The amount of air inhaled by the microbubble generator and the amount of coal slurry circulating will greatly affect the working effect of the microbubble flotation column. The microbubble flotation column is installed with a microbubble generator uniformly distributed around the cylinder. The circulation of the coal slurry and the microbubble generator are used to take in air. The better the dispersion of the bubbles (ie, the smaller the bubble diameter), the flotation effect is The better the gas filling amount increases the flotation clean coal yield, but it will increase the ash content; increase the coal slurry circulation amount can increase the tail coal ash; when the aeration amount and the coal slurry circulation volume are too large, the microbubble flotation column The aeration performance is deteriorated, and the distribution of bubbles along the height of the column is extremely uneven. Excessive bubbles merge with each other to form a gas flow, which increases the degree of turbulence, resulting in liquid level tumbling, thereby reducing sorting selectivity.

Float standard for flotation equipment

According to the requirements of the General Rules for the Inspection of Electromechanical Equipment of Coal Preparation Plant, the flotation equipment must meet the following requirements:

1. The equipment for flotation preparation and preparation, such as slurry preparation, mixing drum, drop box and slurry distributor, should be complete and reliable.

2. The stirring mechanism of the flotation machine, such as the impeller, stator, circulation hole, and inflation hole, should be free of clogging, the gap and opening should be suitable, and the inflation hole should be adjusted flexibly.

3, flotation machine scraping mechanism, scraper should be straight, complete, flexible rotation, uniform, appropriate number of turns, side flat level.

4. Each adjustment gate should be rigorous, level, and flexible.

5, various pipelines (coal, water, oil) valves should be tight, no leakage, the valve should be flexible.

6, fine, tailings chute should be smooth, no damage, deformation.

7. The drug storage tank should be tightly closed without leakage. Fire equipment is ready for use.

8. The fueling device (mechanical or automatic) should be in good condition and reliable.

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