How to make the sticky tailings filter dry and smooth

In recent years, tailings filter press dry platoon is an advanced technology, which solves the safety and environmental protection problems of mine tailings reservoir area. There are still defects of long tail filter pressure filtration and high moisture content of filter cake, which seriously restricts the production of the plant. . When a mine selection plant handles 4 pits, 26 pits and 21 graves of gravel, the concentration of tailings slurry (called “sticky tail slurry”) entering the filter press is low due to the nature of the ore. The viscosity is large, the time of slurry pressurization and manual unloading is long, about twice that of quartzite ore; when more than 2 series of φ5.0 m×5.5 m buffer stirred tanks have the maximum storage time, the buffer tank will be produced. The damage caused by overflowing and polluting the river channel forced the production of grinding flotation in the assembly line to be interrupted and even caused production to stop.

In addition, the energy consumption of the dry tailings and the water content of the filter cake are high, and the tailings discharge is stored in a mud-like state after the temporary storage and transportation point of the plant, so that the forklift, the loader and the car cannot enter at all, and the tail of the paste The mine could not clean the shovel in time. In addition to causing the filter press to stop working, the mineral processing technology indicators were also seriously affected, and even the “one-stop” production plant was shut down. A mine was difficult to handle due to the sticky tail slurry, and the paste tailings were not easy to clean, resulting in a 2.5-month shutdown of the grinding and flotation operation of the plant. The losses were heavy. Therefore, it is easy to make the sticky tailings filter dry and smooth.

Adjusting the production process parameters In the production practice, a mine selection plant has solved the contradiction between the treatment amount of the tailings slurry, the fineness and the crushing and unloading of the glue tailings, and summarized the reduction of the processing capacity or the classifier for the ore properties of different mining area pits. The method of reducing the fineness of overflow and increasing the overflow rate ensures the continuous production.

For example, the ore processing capacity of the workshop is 400 t/d, and the fineness of -200 mesh accounts for 70% to 75%. Considering the influence of ore viscosity, the ore of the No. 6 pit of Jiancao Bay with a grade of 5-6 g/t is controlled at 226-308 t/d, and the fineness of the grinding reaches the standard, thus achieving a small amount of tailings. The unloading time is short and can be matched with the grinding flotation process. For the ore of the No. 21 pit of 1.2-1.4 g/t gravel, the treatment volume is controlled at about 400 t/d, and the final fineness of -200 mesh after grinding is about 66%, which is obviously thicker than the required standard fineness. As a result, the tailings slurry pressure filtration and tailings unloading become dry and normal.

However, there is a limit to reducing the amount of ore processing. The amount of additional water is reduced in the extension weir to increase the concentration of the weir area, reduce the amount of sand return, and increase the overflow volume, thereby reducing the fineness of the overflow. Therefore, reducing the processing capacity of the cohesive or reducing the overflow fineness of the classifier and increasing the overflow is the main measure to adjust the production process parameters.

Change the nature of a sticky ore ore processing plant pulp sticky mud of the tail of a large proportion of its relative decrease in the content of the most simple and effective measures are "incorporated" coarse grained quartz rock material, ie filter aid. The filter aid is to reduce the surface tension of the filtrate, reduce the resistance of the filtrate flowing in the particle gap, and achieve the purpose of strengthening the filtration process, changing the particle size composition of the filter cake, and improving the water permeability. When the mine was planted to treat 6 ore of ore in Jiancao Bay, it was found that the properties of more than 1000 tons of mines were completely different. Although the gold grades in the ore were similar, the former was muddy and the latter was dry. The former was separately selected. The amount is small, the tailings feed and unloading time is long, the beneficiation tailings process flow is stopped, the discontinuity, unevenness and instability are present, and the latter is matched with the latter, and the tailings viscosity problem is solved. , found a way to solve similar problems.

When a mine selects 4 ore ore in Liushagou, the process of tailings in the viscous ore dressing is also discontinuous and stable. Consider the same project contracting team, ore sorting and gold concentrate. The transportation sales settlement method is exactly the same, and the gravel 21 ore ore and the flow sand ditch 4 pit ore are mixed in a ratio of 5:3, and the tailings stickiness problem is obviously alleviated. Similar problems occurred in the selection of the 26-hole ore in the Liushagou. Similarly, the 21-hole ore of the gravel and the 26-hole ore of the Liushagou were mixed in a ratio of 3:1, and the viscosity was greatly improved. That is to say, when the ore viscosity is large, a certain amount of low-grade coarse-grain quartzite or even waste rock needs to be mixed, which can alleviate the influence of ore viscosity on the beneficiation tailings process.

When the slime pulp is filtered, a dense filter cake is formed on the surface of the filter cloth from the beginning, which causes the filter cloth to clog, making filtration difficult. Adding flocculant to the sticky tail slurry can make small particles agglomerate into larger flocs, so that a filter cake with loose and good permeability is formed on the surface of the filter cloth to facilitate filtration. Polyacrylamide is a commonly used flocculant, and lime also has the effect of agglomerating fine ore particles into larger aggregates to accelerate sedimentation.

The dispersant can disperse the slime in the sticky tail slurry, eliminate the harmful effects of the slime adhering to the surface of other minerals, and reduce the viscosity of the tailings. When a mine is dealing with the 6-pit ore of Jiancao Bay with high viscosity, sodium silicate is added as a dispersing agent to reduce the influence of viscosity on the dry discharge of tailings. HSiO3- and silicic acid colloidal particles with high hydration in sodium silicate are directly adsorbed on the surface of fine ore particles, making them hydrophilic to disperse the slime to eliminate the harmful effects of the slime adhering to other mineral surfaces. In addition, sodium silicate has an inhibitory effect on fluorite and calcite . In summary, the "incorporation" of coarse-grained quartzite materials, plus flocculants or dispersants, can change the structural composition and properties of the cohesive ore.

Creating filter press conditions The choice of filter cloth is critical to the filter press efficiency and productivity, and should be selected based on the nature of the slurry and through filtration tests. The production practice of a mine shows that the chemical fiber filter cloth has smoother surface than the cotton cloth filter cloth, low water absorption rate, easy to fall off the filter cake, and high filtration capacity.

The increase of filtration pressure can also change the filtration effect of the sticky tail slurry. The pressure increase can increase the water permeability of the filter cloth and relatively reduce the viscosity of the tailings. When a mine is handling 26 ore of ore with a high viscosity, a KJZ100-39 feed pump (flow rate 228m3/h, head 57.8m, power 75kW/(mg.m-3)) is given to 2 XMZ500 /1500 chamber filter press (filtration area 500m2, filter chamber volume 7m3, filtration pressure ≤0.6MPa, reinforced polypropylene filter plate 101, motor power 5.5kW/(mg.m-3)) beating, changed to 1 The pump beats one filter press, one by one, forming two parallel parallel systems, which reduces the consumption of branch pressure, increases the pressure of the filter press to more than 0.6 MPa, and greatly reduces the feed filter press and manual unloading time. , improve the efficiency of filter press.

The concentration of the concentrated dehydrated sticky tailings slurry before filtration can be greatly reduced, which can greatly reduce the moisture content of the filter cake. Since the pressure filtration ratio is the ratio of the concentration of the tailings slurry after the pressure filtration to the pressure filtration, it is generally constant. From the pressure filtration ratio, it is known that the increase of the concentration before filtration means an increase in the concentration of the filtered product.

According to the mass balance of the filtration process, the formula is obtained:

Q=V(PC)/(1-C/S) (1)

Where: Q is the filter cake yield (t); V is the filtrate volume (m3); C is the slurry concentration (%); S is the filter cake solid content (%); P is the filtrate density (t/m3).

According to formula (1), increasing the concentration of the slurry tends to increase the solid content of the filter cake. A mine selection plant strictly controls the ore dressing water consumption in all aspects of grinding and flotation operations. It is required to use less or no additional water on the premise of ensuring normal production. The effective control of tailings pulp volume has obviously alleviated two series buffer agitating tanks. A phenomenon of full slurry shutdown occurred.

The increase of the concentration before the filter tailings can significantly shorten the filter press time, improve the efficiency of the filter press, and create conditions for increasing the ore processing capacity in the beneficiation workshop. The mine has a low filtration concentration, long feed time, high energy consumption, high viscosity of the filter cake, long unloading time, high labor intensity, and dripping of the filter press process, resulting in slimming of the operating environment. A pile of high-efficiency thickeners with a diameter of 15 m was added before the filter press by demonstrating the "dirty mess", the time spent cleaning up, the high moisture content of the filter cake, the temporary storage and the inconvenience of pulling on site. After more than three months of civil engineering, equipment installation and process debugging, it was still found that the compression zone and the scorpion zone could not be formed in the concentration pool. Therefore, experts from a design institute and a thick machine factory were invited to the site for consultation. The structure of the flocculant, the manufacturer, the molecular weight and the quality of the addition, as well as the thicker taper of the thick pool, the diameter of the cylinder at the center of the tank, and the squeegee on the truss were studied. The mine then carried out the pit ore in different mines. A number of experimental studies on free sedimentation, flocculation sedimentation, and alkalinity addition of flocculant have yielded quite instructive conclusions. The improvement measures are: changing the position of the degassing tank, changing the dosing mode, and adjusting the speed of the truss.

The position of the φ1.5×1.8(m) degassing tank is moved from the intersection of the bridge and the inner edge to the outer side of the upper edge of the concentration tank and the drop is reduced by 1.5 m. After degassing, the tailings slurry slowly and obliquely enters φ2 along the wall of φ159. The 5 m central pumping cylinder does not impact the compression zone and transition zone formed in the concentration tank due to the height of the horizontal feed. The way of discharging the bottom of the tank into the concentration tank from the bottom of the tank is given vertically. The inlet is changed to the horizontal introduction on the equalizing plate to reduce the impact of the potential energy slurry on the concentration zone in the concentration tank.

The flocculant addition position is moved from the outlet of the float sweeping tailings tank of more than 150 m from the thickener to the φ159 oblique pipeline connected to the central receiving tank of the thickener by the degassing tank next to the thickener, and the upper part of the inclined pipe is required. Three ports were sequentially spaced, and the 3-point addition method was used, which was completed by the ZJY-30 automatic program-controlled dosing system of the screw conveyor fan. The dispensing cycle was about 60 min, including 25 min of water (including the screw feeder administration time). ), stirring for 30 min, transfer for 5 min (transfer from the mixing tank to the storage tank). The added water must be clarified, and it is easy to block the pipeline when it contains mud. For this purpose, the mine selection plant has specially welded a sedimentation tank on the bridge, and the overflow is used for the dosing system. In actual production, the amount of flocculant added is 72 g when measured at 20 s. Because the effective volume of the dispensing box is 2.87 m3, the mass fraction of the prepared solution can be determined to be 0.002 5 %, and 576 g of the drug is dispensed for 8 hours per shift. Liquid 22.96 t. Combined with the production practice experience, it is determined according to the experiment that the flocculant unit consumption is 2.5-10 g per ton of ore.

The turret rotation speed in the concentration tank was reduced from 0.25r/min to 0.10 r/min, which fundamentally eliminated the influence of the intermolecular force, Brownian motion and electrostatic elimination of the same charged particles on the sedimentation effect. This mine also draws on the industry experts to take the liquid level of the cylinder in the center of the pool as the middle hole to make the clarified water return to the compression zone and accelerate the zoning progress. At the same time, the concentrated overflow baffle is raised by 250 mm, which increases the effective volume of the concentration tank by 44.16 m3, which ensures the sufficient volume and settlement height of the slurry in the concentration tank.

After the technical improvement, the thickness of the concentrated water layer is about 500 mm, the concentration of the filtration is increased by at least 10%, the feeding time and energy consumption are 1/3 to 1/4 before the technical transformation, and the daily energy saving is 200 kW/( Mg.m-3).h, the unloading time is about 1/4 of the previous one, and the moisture content of the filter cake is about 8 percentage points lower than before the technical transformation; this creates a convenient condition for the temporary storage and transportation, and fundamentally eliminates The "dirty mess", the labor intensity of the post is greatly reduced, the cleaning of the shop floor becomes labor-saving, labor-saving and time-saving, and the operating environment becomes comfortable and elegant.

Conclusion The effect of improving the dry filtration of tailings slurry should be carried out in terms of changing the properties of the tailings slurry, reducing the viscosity of the tailings slurry and changing the conditions of the filter press process.

After the successful reformation of the pre-filtration pre-filtration technology of a mine, the local technical reform was carried out on the two-stage closed-circuit process of the semi- autogenous grinding machine in the 400 t/d beneficiation workshop: the FG-20 spiral classifier in the semi-self-friction closed process The sand returning part is treated by the ZG-40-360 vibrating feeder for the MQY2136 ball mill , and the milled product is graded by the ZSG12×20 vibrating screen. The sieve is fed through the B400 belt and the ZG-40-550 vibrating machine. Semi-autogenous grinding machine, the bottom of the screen is straight from the pipeline into the original mine pump pool. This fundamentally curbs the disadvantages of unbalanced distribution of self-grinding and ball-grinding, so that the daily processing capacity of the concentrator is 450 t from the designed 400 t, and the minimum input grade is 1.2 g/t, and the annual gold production is increased by at least 18 kg. .

At present, the daily processing capacity of ore is moving towards the goal of 500 t and above. The mine purchased two new BF-2.8 flotation machines with 3 slots for roughing and sweeping I, and used the old flotation machine after welding to be used as a sweeping job. The sweeping operation is extended from 3 to 5, and the multi-pass sweeping of the tailings slurry reduces the tailing grade to below 0.3 g/t, and the recovery rate is increased by about 1 percentage point, and the annual increase of gold is 2 kg. After the ore treatment capacity is increased, the output of gold concentrate is increased. The filter press with a filtration area of ​​100 m2 is used instead of the filter press with a filtration area of ​​40 m2, so that the pressure filtration effect and the pressure filtration volume are doubled before the technical transformation. The mine invested 1.5 million yuan to carry out the transformation of the pre-concentration and dewatering pretreatment technology of tailings slurry filtration and dry discharge, creating economic benefits of at least 20 kg of gold production per year and energy saving of 60,000 kW/(mg.m-3).h. The environmental and social benefits brought by it are incalculable; the various ways to improve the effect of dry-slurry slurry filtration and dry discharge are worthy of promotion and reference for the similar tailings filter-filter dry-discharging process.

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