KR102241009B1 - Method and system for floating screen of fluorine-copntaminated soil - Google Patents

Abstract

The present invention relates to a method and a system for fluorine-contaminated soil floating screening that attach specific contaminants such as fluorine present in the soil to air bubbles and then have the same floated for screening. The system for fluorine-contaminated soil floating screening comprises: a hydrogen ion concentration control unit having a floating screening cell with an air flow controller attached thereto and adjusting the pH to 3.5±0.2 by receiving a fluorine-contaminated soil slurry prepared in a predetermined particle size group; a collector agent stirring tank that stirs while adding a collector agent; a foaming agent stirring tank in which a foaming agent is added and stirred after a first reaction time has elapsed after the addition of the collector agent; a floating material recovery unit for injecting compressed air and recovering the floating material after a second reaction time elapses after the addition of the foaming agent; and a filtration-drying unit configured to filter and dry recovered suspended matter and the soil slurry remaining in the floating screening cell after the floating time has elapsed. Specific contaminants such as fluorine present in soil can be attached to air bubbles, floated and screened by using the difference between hydrophobicity and hydrophilicity, which is the physicochemical surface characteristic of particles containing fluorine contaminants and particles without fluorine contaminants.

Description

Fluorine-contaminated soil floating screening method and system {METHOD AND SYSTEM FOR FLOATING SCREEN OF FLUORINE-COPNTAMINATED SOIL}

The present invention relates to a method and system for floating screening of fluorine-contaminated soil, and more particularly, to a method and system for floating screening of fluorine-contaminated soil by attaching a specific contaminant such as fluorine present in the soil to a bubble and then floating it.

Fluoride is regulated as a hazardous substance in the Soil Environment Conservation Act, and its content is regulated at 400ppm, the level of concern for soil pollution. Fluoride is closely related to human life, such as the use of tap water, and is not only toxic, but also causes damage to bones and nervous systems if consumed above the standard. The purification of fluoride-contaminated soil is not purified by physical methods such as soil cultivation, thermal desorption, and conventional soil washing, and chemical treatment causes environmental problems and is rarely used due to lack of economic feasibility.

On the other hand, the fluorine contaminated soil, but also by the generated artificially fluorine compounds discharged, mainly OH in unmoryu contained in soil or rock ^- is generated (OH), and fluorine is naturally substituted. Accordingly, there is a need for a treatment method for effectively separating and removing mica-like minerals as a source of fluorine contamination from fluorine-contaminated soil.

0001) Korean Patent Registration No. 10-1937106 (2019. 01. 03.) 0002) Korean Patent Registration No. 10-0928060 (November 16, 2009) 0003) Korean Patent Application Publication No. 10-2020-0019315 (2020. 02. 24.)

An object of the present invention is to provide a method for floating fluorine-contaminated soil in which a specific contaminant such as fluorine existing in the soil is attached to a bubble by using the difference in hydrophobicity-hydrophilicity of the particle surface and then floated.

Another object of the present invention is to provide a fluorine-contaminated soil floatation screening system that performs the above-described fluorine-contaminated soil floatation screening method.

In order to realize the object of the present invention, a method for floating selection of fluorine-contaminated soil according to an embodiment includes: (i) Injecting a fluorine-contaminated soil slurry prepared in a predetermined particle size into a floating selection cell equipped with an air flow controller, and adjusting the pH to 3.5±0.2; (ii) stirring while adding to the resultant of step (i) a catching agent, which is a flotation screening reagent, which is adsorbed to the surface of mica as a source of fluorine contamination and changes its surface to hydrophobicity to facilitate attachment to air bubbles; (iii) stirring while adding a foaming agent after the first reaction time has elapsed in the resultant of step (ii); (iv) injecting compressed air and recovering the suspended matter after the second reaction time has elapsed in the resultant product of step (iii); And (v) filtering and drying the recovered suspended matter and the soil slurry remaining in the flotation cell after completion of the flotation screening after the passage of the flotation time has elapsed.

In one embodiment, a fluorine-contaminated soil slurry of a particle size group having a diameter of 0.3 mm to 0.5 mm is treated by a rougher flotation, and a fluorine-contaminated soil slurry of an Indian group having a diameter of less than 0.3 mm is treated by a refinery barge. Can be processed.

(여기서, R은 원시료의 무게(g), F는 부유물의 무게(g))에 의해 산출되고, 상기 불소 제거율은

(여기서, Rr'은 원시료의 F 함량, Ff'은 부유물의 F 함량, Ss'은 잔유물의 F 함량, S는 잔유물의 무게(g), r'은 원시료내 F 농도(mg/kg), s'은 잔류물내 F 농도(mg/kg))에 의해 산출될 수 있다. In one embodiment, the method of floating fluoride-contaminated soil is a step of calculating a yield of floating product (YF, or contaminated soil removal rate) and a removal rate of fluorine (Removal of fluoride by floation, Rm) through weight measurement. It may further include. Here, the yield of the floating material is,

(Where, R is the weight of the raw material (g), F is calculated by the weight of the floating material (g)), the fluorine removal rate is

(Where, Rr' is the F content of the raw material, Ff' is the F content of the suspension, Ss' is the F content of the residue, S is the weight of the residue (g), and r'is the F concentration in the raw material (mg/kg). , s'can be calculated by the F concentration in the residue (mg/kg)).

In one embodiment, the catcher may include Armac-C or Armac-T. Conversely, the Armac-T may be 300g/ton.

In one embodiment, the foaming agent may include AF65. Here, the AF65 may be 50g/ton.

In one embodiment, the compressed air may be injected at an air injection amount of 2.0 L/min.

In order to realize another object of the present invention, the fluorine-contaminated soil floating screening system according to an embodiment includes a floating screening cell equipped with an air flow rate controller to receive a fluorine-contaminated soil slurry prepared in a predetermined particle size group. a hydrogen ion concentration control unit that adjusts the pH to 3.5±0.2; A water catcher stirring tank for adsorbing on the surface of mica, which is a source of fluorine contamination, to change the surface to hydrophobicity and stirring while adding a catcher, which is a floating screening reagent that facilitates attachment to the air bubbles; A foaming agent stirring tank for stirring while adding a foaming agent after the first reaction time has elapsed after the addition of the foaming agent; A floating material recovery unit for injecting compressed air and recovering the floating material after the second reaction time has elapsed after the addition of the foaming agent; And a filtration-drying unit for filtering and drying the recovered suspended matter and the soil slurry remaining in the floatation cell after completion of the floatation after the floatation time has elapsed.

(여기서, R은 원시료의 무게(g), F는 부유물의 무게(g))에 의해 산출된다. 또한 상기 불소 제거율은

(여기서, Rr'은 원시료의 F 함량, Ff'은 부유물의 F 함량, Ss'은 잔유물의 F 함량, S는 잔유물의 무게(g), r'은 원시료내 F 농도(mg/kg), s'은 잔류물내 F 농도(mg/kg))에 의해 산출될 수 있다. In one embodiment, the fluorine-contaminated soil floating screening system is calculated to calculate a yield of floating product (YF, or contaminated soil removal rate) and a fluorine removal rate (Removal of fluoride by floation, Rm) through weight measurement. It further includes wealth, but the yield of the floating material,

(Where R is the weight of the raw material (g), F is calculated by the weight of the floating material (g)). In addition, the fluorine removal rate is

(Where, Rr' is the F content of the raw material, Ff' is the F content of the suspension, Ss' is the F content of the residue, S is the weight of the residue (g), and r'is the F concentration in the raw material (mg/kg). , s'can be calculated by the F concentration in the residue (mg/kg)).

According to the method and system for floating screening of fluorine-contaminated soil of the present invention, specific contaminants such as fluorine present in the soil are determined by using the difference in hydrophobicity-hydrophilicity, which is a physicochemical surface characteristic of particles containing and without fluorine contaminants. After attaching to the air bubble, it can be floated and sorted.

1 is a conceptual diagram for explaining floating screening.
2A and 2B are block diagrams schematically illustrating a soil pollution purification system employing a fluorine-contaminated soil floatation system according to the present invention.
3 is a block diagram for explaining a floating screening system for fluorine contaminated soil according to an embodiment of the present invention.
4 is a flow chart of a demonstration experiment for floating screening of fluorine-contaminated soil.
5 is a graph showing the calculation rate of micro-floating screening of standard mica according to the pH of the flotation screening water.
6 is a graph showing the yield of micro-floating selection according to pH for mixed minerals.
7A is a graph showing the calculation rate for micro-floating selection of Undo-ryu according to the type of catcher and the particle size group.
7B is a graph showing the calculation rate for micro-floating selection of mica according to the type and amount of the catcher.
8 is a particle size distribution diagram of a floating micro-float according to the type and amount of the catcher.
9 is a graph showing the results of flotation selection according to the amount of Armac-T added in medium and low concentration fluorine-contaminated soil.
10 is a graph showing the results of flotation selection according to the amount of Armac-T added in medium and low concentration fluorine-contaminated soil.
11 is a graph showing the results of flotation selection according to the amount of Armac-T added in high-concentration fluorine-contaminated soil.
12 is a graph showing the results of flotation selection according to the amount of Armac-T added in high-concentration fluorine-contaminated soil.
13 is a graph showing the results of the mainbu line-refining line of high-concentration contaminated soil.
FIG. 14 is a graph showing the results of a fluorine-contaminated soil with a fluorine concentration of 1,044 mg/kg (first flotation sorting) and refinement flotation (second flotation sorting).
FIG. 15 is a graph showing the results of a fluoride-contaminated soil with a fluorine concentration of 1,044 mg/kg (first flotation sorting)-regrinding-refining flotation line (second flotation sorting).
16 is a graph showing the results of flotation of contaminated soil at medium and low concentrations by slurry concentration.
17 is a graph showing the result of flotation of high-concentration contaminated soil by slurry concentration.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. In the present invention, various modifications may be made and various forms may be applied, and specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific form disclosed, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance the possibility of the presence or addition.

In addition, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present application. Does not.

In general, when solid particles dispersed in water are larger than the specific gravity of water, the gravity acting thereon is greater than the buoyancy force, so that they settle. However, when solid particles adhere to the air bubbles, the buoyancy acting on them becomes greater than gravity and floats to the water surface. Bubbles can attach to solid particles in this way only when their surface is hydrophobic.

Therefore, the float flotation is not using physical properties between solid particles, but by using the difference in physical and chemical properties of the surface of solid particles.

In recent years, not only waste treatment fields such as recovery of valuable minerals from tailings, which are mine waste (or mineral debris), mutual separation of waste plastics, ink removal from waste paper, and coal ash refining, as well as floating heavy metal-containing particles from heavy metal contaminated soil. It is also used as a soil purification method to remove it.

1 is a conceptual diagram for explaining floating screening.

Referring to FIG. 1, when air bubbles are generated by blowing air into a slurry in which a solid mixture is suspended, hydrophobic particles adhere to the bubbles and float on the water surface. ) Particles are a sorting method that uses the properties that remain in the slurry.

As the kind of floating screening, it can be divided into direct flotation and reverse flotation depending on whether the target material is floated or left in a suspension, and whether a plurality of target materials is suspended or a single target material Depending on whether or not to float, they are roughly classified into bulk flotation and differential flotation.

Heavy metal contaminated soil is purified by applying reverse flotation screening, which floats and removes heavy metal substances such as heavy metal-containing minerals and metals.

On the other hand, factors influencing the flotation selection include solid particle size, slurry concentration, stirring speed, air injection amount, slurry pH and Eh, and the type and amount of flotation screening reagents (water trapping agent, foaming agent, conditioner).

In the flotation sorting, various reagents are added to the slurry in order to increase the difference in flotation between the ore mineral and the gangue mineral so that sorting can be performed effectively. Reagents added for these various purposes are collectively referred to as flotation reagents.

The flotation screening reagent is largely divided into a collector, a foamer, and a modifier, according to its function. The catcher is a flotation screening reagent that adsorbs on the surface of a mineral to be suspended and changes the surface to hydrophobic to facilitate attachment to air bubbles. The foaming agent is a flotation screening reagent that not only facilitates generation of fine bubbles by lowering the surface tension of water, but also improves the stability of bubbles. The conditioner is a flotation screening reagent that imparts flotation conditions for effective flotation between minerals.

The conditional agent may be further subdivided into an inhibitor (depressant or depressing agent), an activator, a pH adjusting agent, an Eh adjusting agent (redox agent), a dispersant, and the like. Here, the inhibitor is a reagent that inhibits floating by changing a hydrophobic surface to a hydrophilic surface or by interfering with the adsorption of a catcher, and the activator is recombined to a mineral that is difficult to adsorb by a catcher or a mineral that has already been inhibited and has become non-floating. It is a reagent that facilitates the adsorption of the water trapping agent. The pH adjuster is a reagent that adjusts the pH of the suspension, the Eh adjuster is a reagent that adjusts the redox potential of the suspension, and the dispersant disperses the particles in the suspension to prevent the hydrophilic particles from being entrapped. It is a reagent.

Float screening is made more effectively by using a combination of several of these flotation screening reagents instead of alone.

2A and 2B are block diagrams schematically illustrating a soil pollution purification system employing a fluorine-contaminated soil floatation system according to the present invention.

2A and 2B, the fluorine-contaminated soil purification system includes an input hopper (T-201), an input conveyor (T-202), a wet crusher (T-203), a wet magnetic separator (T-204), and sulfuric acid. Storage tank (CT-201), sulfuric acid injection pump (CP-201), water catcher storage tank (CT-202), water catcher injection pump (CP-202), foam storage tank (CT-203), foam injection pump ( CP-203), Float Sorting Conditioner (T-205A/B), Float Sorter (T-206), Float Sorter Transfer Tank (T-206-1), Intermediate Transfer Water Tank (T-208), Neutralizer Storage Tank (CT -204), sedimentation tank (T-209), coagulation tank (T-210), coagulant storage tank (CT-205), sedimentation tank (T-211), sludge storage tank (T-212), water collection tank scum tank (T-213) ), process water storage tank (T-214), make-up water storage tank (T-215), filter press (T-216A, T-216B), wet cleaning device (T-217), compressor (T-218). .

Fluorine contaminated soil is introduced into the input hopper (T-201) to remove impurities. At the input port of the input hopper (T-201), a screen is provided to remove impurities mixed with the fluorine-contaminated soil. The fluorine-contaminated soil is removed from impurities such as stones with a particle size of 2 mm or more, and the input conveyor (T- 202) to the wet crusher (T-203).

The input conveyor (T-202) extends from the lower end of the input hopper (T-201) to the wet crusher (T-203) and transfers the fluorine-contaminated soil from which impurities are removed to the wet crusher (T-203) in a fixed amount. .

The wet crusher (T-203) crushes the fluorine-contaminated soil supplied from the input conveyor (T-202) to less than 0.05mm under wet conditions. And a crushing rod capable of crushing soil while rotating in an internal space connected to the discharge port. The fluorine-contaminated soil injected with water into the inner space through the supply port of the wet crusher (T-203) is crushed by the rotating crusher. The fluorine-contaminated soil crushed to less than 0.05mm is transferred to the wet magnetic separator (T-204) through the outlet of the wet crusher (T-203).

The wet magnetic separator (T-204) separates weakly magnetic minerals from the fluorine-contaminated soil supplied from the wet crusher (T-203), sorts and disposes the waste of magnetic components, and floats the remaining fluorine-contaminated soil. Supply to (T-205A/B).

Sulfuric acid is accommodated in the sulfuric acid storage tank (CT-201), and the stored sulfuric acid is supplied to the flotation conditioner (T-205A/B) by a sulfuric acid injection pump (CP-201). The catcher storage tank (CT-202) contains a catcher, a flotation screening reagent that absorbs the surface of mica, which is a source of fluorine contamination, and changes the surface to hydrophobic so that it can be easily attached to the air bubbles, and the stored catcher is a catcher injection pump. It is supplied to the floatation conditioner (T-205A/B) by (CP-202). The foaming agent is accommodated in the foaming agent storage tank (CT-203), and the stored foaming agent is supplied to the flotation sorting conditioner (T-205A/B) by the foaming agent injection pump (CP-203).

The flotation sorting conditioner (T-205A/B) is supplied to the fluorine-contaminated soil provided by the wet magnetic separator (T-204) and the sulfuric acid and water catcher injection pump (CP-202) supplied by the sulfuric acid injection pump (CP-201). The non-magnetic soils selected by the wet magnetic separator (T-204) are mixed with chemicals such as the foaming agent supplied by the foaming agent and the foaming agent supplied by the foaming agent injection pump (CP-203). The flotation sorter (T-206) floats and removes substances (particles) that have accumulated pollutant concentration in the soil for chemicals and soil mixtures that have passed through the flotation sorting conditioner (T-205A/B). Selected soil is transferred to the waste sedimentation tank, and the treated soil is transferred to the sedimentation site according to the initial inflow concentration.

In the flotation sorter (T206A/B), mica is floated using a catcher and a foaming agent, and the floated mica is transferred to the settling tank (T-211) through the floating drainage pump (P-202). Purified soil that has not been floated is transferred to the flotation separator transfer tank (T-206-1).

The flotation separator transfer tank (T-206-1) is transferred to the screw conveyor (T-207) using a sand transfer pump (P-203). The dehydrated purified soil is discharged and the process water is transferred to the intermediate transfer and storage tank (T-208).

The process water transferred from the screw compressor (T-207) is accommodated in the intermediate transfer storage tank (T-208), and the received process water is transferred to the grit chamber (T-209).

The neutralizing agent is accommodated in the neutralizing agent storage tank (CT-204), and the neutralizing agent is supplied to the gritroom (T-209) by the neutralizing agent injection pump (CP-204).

Residual soil for flotation is transported with water to the sedimentation site (T-209). As for the residual soil transferred to the sedimentation site (T-209), the soil with high specific gravity is returned due to the difference in specific gravity, and re-selection proceeds, and the soil that has not been returned is transferred to the coagulation tank (T-210).

In the coagulant tank (T-210), the coagulant is introduced from the coagulant storage tank (CT-205) and stirred to floculate the fine soil, and is transferred to the settling tank (T-211) through the coagulation drainage pump (P-206).

The coagulant storage tank (CT-205) contains a coagulant, and the coagulant is supplied to the coagulant tank (T-210) and the settling tank (T-211) by the polymer injection pump (CP-205).

The sedimentation tank (T-211) was manufactured to precipitate fine soil and mica, and after sedimentation, it was transferred to the sludge storage tank (T-212) and then transferred to the filter presses (T-216A, T-216B).

The sludge settled in the sludge storage tank T-212 is accommodated, and the stored sludge is supplied to the filter presses T-216A and T-216B. In filter presses (T-216A, T-216B), fine soil and mica are converted into cakes using a filter and then discharged, and the filtered process water is transferred to the process water tank to be recycled as process water.

The process water storage tank (T-214) is installed to recycle process water, and the insufficient process water is provided from the make-up water storage tank (T-215).

The filter press (T-216A, T-216B) is a device that dewaters the treated soil after the eluted treated soil or floating screening. Fine soil of less than 0.05mm transferred using the sludge transfer pump (P-208A/B) in the thickening tank Is discharged to the dehydration cake and transported to the storage in the treatment plant, and the dehydrated filtrate is transferred to the process water storage tank (T-214) for recycling in the washing water process.

The wet cleaning device (T-217) removes dust and possible gases generated by the device by wet cleaning.

The compressor (T-218) is used to operate the air diaphragm (AOD) pump and is used to inject air into the filter press (T-216A, T-216B).

3 is a block diagram for explaining a floating screening system for fluorine contaminated soil according to an embodiment of the present invention.

3, the fluorine-contaminated soil floating screening system according to an embodiment of the present invention includes a hydrogen ion concentration control unit 110, a water catcher stirring tank 120, a foaming stirring tank 130, and a floating material recovery unit 140. ), a filtration-drying unit 150, and a calculation unit 160.

The hydrogen ion concentration control unit 110 includes a floating screening cell equipped with an air flow rate controller to receive a fluorine-contaminated soil slurry having a predetermined particle size group and adjust the pH to 3.5±0.2. Here, the fluorine-contaminated soil slurry of a particle size group having a diameter of 0.3mm to 0.5mm can be treated by a rougher flotation, and a fluorine-contaminated soil slurry of the Indian army having a diameter of less than 0.3mm is treated by a refinery. Can be. When treated with a coarse barge, the slurry concentration is about 30%, and when treated by a refining barge, the slurry concentration is about 20%.

The catcher agitating tank 120 is a flotation screening reagent that adsorbs to the surface of the mineral to be suspended and changes the surface to hydrophobic to facilitate attachment to the air bubbles.A catcher such as Armac-C or Armac-T is used per ton of 200 to While adding at 400 g, the mixture is stirred at a stirring speed of, for example, 1200 rpm. Here, Armac-T may be 300g/ton.

The foaming agent stirring tank 130 is stirred at a stirring speed of, for example, 1200 rpm while adding 100 to 200 g per ton of the foaming agent after the first reaction time has elapsed after the addition of the foaming agent. The foaming agent includes AF65. Here, AF65 may be 50 g/ton.

The floating material recovery unit 140 injects compressed air and recovers the floating material after the second reaction time has elapsed after the addition of the foaming agent. Here, the compressed air is injected at an air injection amount of 2.0 L/min. In addition, the recovery time of the floating matter is approximately 2 minutes.

The filtration-drying unit 150 filters and dries the recovered suspended matter and the soil slurry remaining in the floatation cell after the floatation period has elapsed.

The calculation unit 160 calculates a yield of floating product (Y _F , or contaminated soil removal rate) and a fluorine removal rate (Removal of fluoride by floation, R _M ) through weight measurement. In this embodiment, the yield (Y _F ) of the floating material may be calculated by Equation 1 below.

[Equation 1]

(여기서, R은 원시료의 무게(g), F는 부유물의 무게(g))

(Where, R is the weight of the raw material (g), F is the weight of the floating material (g))

In addition, the fluorine removal rate (R _M ) may be calculated by Equation 2 below.

[Equation 2]

(여기서, Rr'은 원시료의 F 함량, Ff'은 부유물의 F 함량, Ss'은 잔유물의 F 함량, S는 잔유물의 무게(g), r'은 원시료내 F 농도(mg/kg), s'은 잔류물내 F 농도(mg/kg))

(Where, Rr' is the F content of the raw material, Ff' is the F content of the suspension, Ss' is the F content of the residue, S is the weight of the residue (g), and r'is the F concentration in the raw material (mg/kg). , s'is the concentration of F in the residue (mg/kg))

Then, in order to explain the flotation screening of fluorine-contaminated soil according to the present invention, an experimental example of flotation screening will be described below.

For the flotation screening experiment of fluorine-contaminated soil, the geotechnical characteristics of each stratum, the geotechnical characteristics of each stratum, and the distribution status and weathering of the fluorine-contaminated soil were identified, and the structural state of the stratum and the depth of the supporting layer were confirmed.

The rocks of the site contain quartz (29%), feldspar (29%), fluorspar (0.1), amphibole (1.1), and mica (40.6%). It contains small amounts of smectite. As a result of separating and analyzing only mica using a quantitative analysis program based on the Rietveld method using XRD diffraction analysis results, gneiss distributed in the task section contains a large amount of mica, and mica (40.6%) is muscovite (15.2%). ), biotite (13.3%), and lithium mica (12.1%). As a result of performing the analysis on rock samples, it was judged that the fluorine content was not increased due to pollution from the surface, but that the fluorine concentration was high due to the influence of minerals in the rock.

The sources of fluoride (F) contamination in fluoride-contaminated soil are mainly mica (muscle mica, biotite, lithium mica) and trace amounts of fluorspar (CaF2). Therefore, in order to purify fluorine-contaminated soil, it will be possible only by applying a screening technology applied to remove persistent heavy metals rather than a purification technology such as pickling.

The screening technology is a treatment technology that uses differences in physical properties (shape, density, susceptibility, etc.) or physicochemical surface properties (hydrophobicity-hydrophilicity) of particles containing and without fluorine contaminants. It is diverse, such as sorting, flotation sorting, etc., and sorting equipment for it is also very diverse according to the particle size distribution of the treated material.

However, when particles containing fluorine contaminants and particles not containing fluorine contaminants exist as free particles, a screening technique can be applied. Therefore, when particles containing fluorine contaminants and particles that do not contain fluorine contaminants exist in a locked state, the degree of liberation of these particles is at least 85% so that they exist as free particles. After grinding to the degree, it is sorted.

1. Floating screening test

Mica standard samples (biotite and muscovite mica) and large mica specimens present in fluorine-contaminated soil were collected by hand picking, and then dry pulverized and sieved mica samples were subjected to micro-floating screening empirical experiments. The micro-floating sorter (XFG50-100 type) has a floating sorting cell capacity of 200 ㎖, and the amount of sample used in a single factor test is about 1~2g. Since only pure mica samples are used as the result of flotation, the mica removal rate or fluorine removal rate can be predicted by measuring only the weight of the suspended sample without fluorine (F) analysis and calculating the floatation yield (%). Therefore, a preliminary micro-floating screening test was performed on fluorine-contaminated soil in order to quickly and easily grasp the flotation screening reagent suitable for floating screening of mica and the flotation screening conditions.

The demonstration experiment for flotation screening for purification of fluorine-contaminated soil was conducted using a Sub-A type flotation screener (KHD Humboldt Wedag AG) equipped with an air flow controller.

That is, a fluorine-contaminated soil slurry prepared at a certain concentration is placed in a floating screening cell having a capacity of 1.5*, a certain flotation screening reagent is added, and a certain amount of condensation is performed while stirring for a certain period of time while conditioning. Air was injected to recover the suspended matter and the residue. After the flotation screening is completed, the recovered flotation and the soil slurry remaining in the flotation cell are vacuum filtered, and the filtering cake is completely dried to measure the weight of the suspended matter (contaminated soil) and the residual material (purified soil). And analyzed by the alkaline leaching method.

(여기서, R은 원시료의 무게(g), F는 부유물의 무게(g))에 의해 산출된다. In this experimental example, the yield of floating product (YF), that is, the contaminated soil removal rate (%) is shown in Equation 1 above.

(Where R is the weight of the raw material (g), F is calculated by the weight of the floating material (g)).

(여기서, Rr'은 원시료의 F 함량, Ff'은 부유물의 F 함량, Ss'은 잔유물의 F 함량, S는 잔유물의 무게(g), r'은 원시료내 F 농도(mg/kg), s'은 잔류물내 F 농도(mg/kg))에 의해 산출된다. In addition, the fluorine (F) removal rate (Removal of fluoride by floation, RM) is shown in Equation 2 above.

(Where, Rr' is the F content of the raw material, Ff' is the F content of the suspension, Ss' is the F content of the residue, S is the weight of the residue (g), and r'is the F concentration in the raw material (mg/kg). , s'is calculated by the F concentration in the residue (mg/kg)).

[Table 1] shows the flotation screening reagents such as pH adjuster, water catcher, and foaming agent used in this flotation screening demonstration experiment. Here, tap water was used as the experimental water.

[Table 1]

2. Micro-floating screening of standard mica

Micro-floating screening was performed on samples obtained by dry grinding of standard mica (biotite and muscovite mica) and then sieved.

Figure 4 is a flow chart of fluorine-contaminated soil floating screening demonstration experiment.

Referring to FIG. 4, after wet grinding a soil sample, wet grinding, contaminated soil is added. Then, after adjusting the pH, adding a reagent, and adjusting the amount of air, the foam is recovered. Then, vacuum filtration was performed to obtain a filter cake, and after drying the obtained filter cake, a flotation product was obtained.

The flotation result of the demonstration experiment for micro-floating screening uses only pure mica samples, so the floatation yield (%) was calculated by measuring only the weight of the suspended sample without fluorine (F) analysis.

Therefore, in order to quickly and easily grasp the flotation screening reagent and flotation screening conditions suitable for mica flotation screening, a preliminary micro-floating screening test was performed prior to the test of fluorine-contaminated soil. At this time, the amount of standard mica used (0.5~0.075㎜) is 1g, the catching agent Armac-T is 1,000g/ton, the foaming agent (AF 65) is 1 drop, the air injection volume is 80ℓ/hr, and the flotation screening reagent The condition provision time was 3 minutes each, and the floating time (foam recovery time) was fixed at 5 minutes, etc., and a floating screening demonstration experiment was performed. Tap water was used as experimental water.

5 is a graph showing the calculation rate of micro-floating screening of standard mica (biotite, musculoskeletal mica) according to the pH of the floating screening water.

Referring to FIG. 5, it can be seen that as the pH of the flotation aqueous solution goes from strong acid to neutral, the yield rate of flotation for both biotite and muscovite mica increases.

6 is a graph showing the calculation rate of micro-floating selection according to pH for mixed minerals (biotite + quartz).

Referring to FIG. 6, as in the micro-floating screening rate of standard mica (biotite, musculoskeletal mica) shown in FIG. 5, the rate of floating screening increased as the pH went from strong acid to neutral. The amount of the mixed mineral sample used at this time was 1 g (0.5 g of black mica + 0.5 g of muscovite mica), and the efficiency of selection of biotite and quartz could not be determined only by the yield of the mixed minerals.

However, from [Table 2], it can be seen that the pH of the flotation screening solution is 3.5 in terms of screening efficiency of biotite and quartz and wastewater treatment of water. Here, the screening efficiency (%) was calculated by Equation 3 below.

[Equation 3]

[Table 2] shows the results of micro-floating selection of mixed minerals (biotite + muscovite mica) according to pH.

3. Micro-floating screening of mica in contaminated soil

Large mica specimens present in fluorine-contaminated soil were collected by hand picking, and then micro-floating screening empirical experiments were performed on the mica samples that were sieved after dry grinding. The flotation result of the demonstration experiment for micro-floating screening used only mica samples, so as with the standard mica sample, only the weight of the suspended sample was measured without fluorine (F) analysis to obtain the floatation yield (%). . At this time, the amount of mica used is 1g, the foaming agent (AF 65) is 1 drop, the air injection amount is 80*/hr, the conditional time of the flotation screening reagent is 3 minutes each, and the floating time (foam recovery time) is 5 minutes. It was fixed with a back and carried out a demonstration experiment for floating screening. In addition, Armac-T and Armac-C were used as water catchers, and tap water was used as experimental water.

7A is a graph showing the calculation rate for micro-floating selection of Undo-ryu according to the type of catcher and the particle size group. In particular, it shows the calculation rate of micro-floating screening for the type of water catcher (addition 1,000g/ton) (Armac-C, Armac-T) and the particle size group of mica under the condition that the pH of the floating screening water is 3.5±0.2. , Regardless of the type of catcher (Armac-C, Armac-T), it can be seen that the smaller the particle size group, the higher the floating screening yield.

7B is a graph showing the calculation rate for micro-floating selection of mica according to the type and amount of the catcher. In particular, it shows the yield of micro-floating screening for mica less than 0.5 mm depending on the type of catching agent (Armac-C, Armac-T) and the amount added under the condition that the pH of the floating screening water is 3.5±0.2. Regardless of the type (Armac-C, Armac-T), as the addition amount increases, the flotation output also increases. And it can be seen that the calculation rate of flotation selection by Armac-C is higher than that of Armac-T.

From the results shown in Fig. 7b, Armac-C is a more effective catcher than Armac-T for particle size group floatation of 75 μm or less, and Armac-T is slightly less than Armac-C for particle size group mica floatation of 0.5 to 0.3 mm. It was judged to be a more effective catcher. To confirm this, particle size analysis was performed on the floating matter by micro-floating screening.

8 is a particle size distribution diagram of a floating micro-float according to the type and amount of the catcher.

Figure 9 shows the particle size distribution of mica and micro-floating sorting suspended matter less than 0.5 mm. When the amount of the catcher added is 1,000 g/ton, the float obtained by Armac-T (tallow-acetic acid salts of n-alkyl amines) It can be seen that the cumulative particle size (D90) of 90% passage is 382 µm, which is greater than 309 µm obtained by Armac-C (coconut-acetic acid salts of n-alkyl amines).

As can be seen in FIGS. 8 and 9, Armac-C is a much more effective catcher than Armac-T for floating mica of fine particles of 75 μm or less, and Armac-T rather than Armac-C for floating mica of a particle size of 0.3 mm or more. You can see that is a slightly more effective catcher.

However, in both Armac-C and Armac-T, the floatation rate of mica in the particle size group of 0.5 to 0.3 mm was very low, around 7%.

4. Demonstration test of flotation selection of contaminated soil

The particle size group of contaminated soils input to the physical soil washing process is 2~0.05㎜. In other words, the soil from which gravel of 2 mm or more has been removed through trommel passes through a two-stage wet classifier, and particulates of less than 0.05 mm are removed as waste, and is divided into a 2~0.5㎜ particle size group and a 0.5~0.05㎜ particle size group. It is put into the washing process.

Therefore, the flotation screening test was conducted under the catching agent Armac-T, which was found to be somewhat more effective in the flotation rate of the particle size group of 0.5 to 0.3 mm than the flotation of particulate mica, and the flotation screening condition of pH 3.5 suitable for flotation screening of mica and quartz. .

First, put the fluorine-contaminated soil slurry prepared in a predetermined particle size group into a Sub-A type floatation cell (capacity 1.5ℓ) equipped with an air flow controller, and adjust the pH to 3.5±0.2, and then the predetermined floatation screening Reagents (foaming agent, foaming agent) are added, conditioning is performed while stirring for a certain period of time, and the suspended matter is recovered for a certain period of time while injecting a certain amount of compressed air. After the flotation screening is complete, the recovered flotation and the fluorine-contaminated soil slurry remaining in the flotation cell are vacuum filtered, and the filter cake is completely dried to measure the weight of the suspended matter (contaminated soil) and the residue (purified soil). It was self-analyzed by leaching.

The yield of floating matter (%), that is, the contaminated soil removal rate (%) and the fluorine removal rate (%) can be calculated.

end. Floating screening efficiency according to the amount of water catcher added

As a result of floating screening according to the amount of Armac-T added to medium and low concentration fluorine-contaminated soil (D90=484㎛) with a fluorine concentration of 498 mg/kg, if the amount of water catcher added 100g/ton, 4% of suspended matter (contaminated soil) was removed and fluorine Fig. 25.2% was removed, and the fluorine concentration in the residual soil became 390 mg/kg, satisfying the 2 area concern criterion.

9 is a graph showing the results of flotation selection according to the amount of Armac-T added in soil (D90 = 484 μm) contaminated with medium and low concentration fluorine (498 mg/kg). 10 is a graph showing the results of flotation selection according to the amount of Armac-T added to soil contaminated with medium and low concentration fluorine (595 mg/kg) (D90 = 310 μm). 11 is a graph showing the results of flotation selection according to the amount of Armac-T added in soil contaminated with high concentration fluorine (1054 mg/kg). 12 is a graph showing the results of flotation selection according to the amount of Armac-T added in high-concentration fluorine-contaminated soil (D90 = 552 μm). Here, the second area is an area in which the land, salt farm, large, warehouse site, river, oil, oil, water supply site, sports site, amusement park, religious site, and hybrid site according to the Act on the Construction and Management of Geospatial Information.

On the other hand, as the amount of water catcher was increased, the suspended contaminated soil increased and the fluorine removal rate increased. At 500 g/ton, the contaminated soil removal rate was 25%, and the fluorine concentration in the residual soil was 240 mg/kg. The removal rate was 63.7%.

This time, the fluorine concentration was a little high at 595 mg/kg, but the particle size group was a small medium/low concentration fluorine-contaminated soil amount (D90 = 310 μm), and the result of flotation selection according to the amount of Armac-T added (shown in FIG. 11), If the amount of water catcher added was 400g/ton, 21% was removed as a floating matter, and 47.4% of fluoride was also removed, and the fluorine concentration in the residual soil was 397mg/kg, satisfying the level of concern for the 2nd region. At this time, the flotation screening conditions were 2.5% slurry concentration, the conditional time was 2 minutes for each flotation screening reagent, the air injection amount was 2ℓ/min, and the foam recovery time was 2 minutes.

In addition, the result of floating screening according to the amount of Armac-T added (shown in Fig. 12) for high-concentration fluorine-contaminated soil with a fluorine concentration of 1,054 mg/kg (D90 = 478 μm), and contamination floating as the amount of water catcher added increased. The soil also increased and the fluoride removal rate increased, but even when the fluoride removal rate was increased to 600 g/ton, the contaminated soil removal rate was 24% and the fluoride removal rate was 55.7%, but the fluorine concentration in the residual soil was 647 mg/kg, which did not satisfy the standard of concern for the 2nd region.

This time, three times of flotation screening under the same flotation conditions, such as 10% slurry concentration and 400 g/ton of Armac-T addition amount, was performed on high-concentration fluorine-contaminated soil (D90=552㎛) with a fluorine concentration of 1,044 mg/kg. As shown in Fig. 13, the average floating ratio was 24%, the fluorine removal ratio was 46%, and the residual fluorine concentration was 721 mg/kg.

13 is a graph showing the results of the mainbu line-refining line of high-concentration contaminated soil.

In this way, regardless of the concentration of fluorine-contaminated soil, if the amount of Armac-T added is 400-500g/ton, the contaminated soil removal rate can be removed by 20-25% and fluorine can be removed by 50-60%, which greatly affects the feeding size. I understood that I was receiving it.

Therefore, in the case of high-concentration fluoride-contaminated soils with a fluorine concentration of 1,000 mg/kg or more, in order to satisfy the concern criterion for area 2, a refinery to remove more than 60% of fluoride, i.e., mica, which is a source of fluoride contamination, is further floated and removed. It is desirable to perform (second flotation screening).

I. High-concentration fluoride-contaminated soils (1st floating screening)-Refining barge (2nd floating screening)

FIG. 14 is a graph showing the results of a fluorine-contaminated soil with a fluorine concentration of 1,044 mg/kg (D90 = 552 μm) and a refinery line (first flotation screening) and a refinery flotation line (second flotation screening).

Slurry concentration was 10%, Armac-T added amount 400g/ton in the jobu ship, and the refining ship was carried out with a slurry concentration of 10% and a catcher added amount 200 g/ton for the residues of the Jobu ship.

As can be seen from the graph, refining was performed, but the contaminated soil removal rate was very low at 7% based on the rapid light of the grandfather ship, and the fluorine removal rate did not increase significantly to 17.4%. That is, the cumulative contaminated soil removal rate of the Jobu-Seon-Jeongbu-seon was 29% and the cumulative fluorine removal rate was 56.7%, and the fluorine concentration of the final residual soil was 637 mg/kg, which did not satisfy the level of concern. In order to clarify this, particle size analysis was performed on the rapid light, suspended solids, and residues of the shipbuilding and refinery ships.

As shown in Fig. 15, it can be seen that in the particle size distribution diagram of the soil sample (rapid light) supplied to the Jobu boat (first floating screening), a particle size group of 350 µm or more is hardly seen in the Jobu boat float and is present in the Jobu boat residue as it is. there was. In addition, it can be seen that the particle size group of 350 μm or more, which is present in the particle size distribution of the rapid light (remnants of the Jobu ship) supplied to the refinery (second floating screening), is hardly visible in the floatation of the refinery but still exists in the residue of the refinery. there was.

Therefore, it was judged that a good flotation purification effect could be expected only when the particle size group of soil samples (rapid light) supplied for flotation sorting was 350㎛ or less.

All. High-concentration fluoride-contaminated soils (1st floating screening)-Regrinding-Refining ships (2nd floating screening)

15 is a graph showing the results of the Jobu line (first flotation screening)-regrind-purification bar line (second flotation screening) targeting high-concentration fluorine-contaminated soil (D90=552 μm) with a fluorine concentration of 1,044 mg/kg.

Referring to FIG. 15, a particle size distribution diagram of light, floating matter, and remnants of the coarse line (primary line) and the refinery line (second line) is shown.

In the Jobu Ship, the slurry concentration was 10% and the amount of Armac-T added was 400 g/ton, and the residues of the Jobu Ship were then wet-milled with a rod mil so that the 90% cumulative particle size (D90) was 300 µm, and then catcher. For the sake of brewing, ½ of the added amount of jobu-seon was added and refining was carried out.

As can be seen from FIG. 15, as a result of performing the refining barge after re-crushing, the contaminated soil removal rate increased a lot to 34%, and the fluorine removal rate also increased significantly to 70%, so that the cumulative soil removal rate of the jobu line-refining barge 50% and The cumulative fluoride removal rate was 83%, and the fluorine concentration in the final residual soil was 355 mg/kg, which satisfies the level of concern for the 2nd region.

To clarify this, particle size analysis was performed on the rapid light, suspended solids, and residues of the shipbuilding and refinery ships. In the particle size distribution of soil samples (rapid light) supplied to the Jobu ship (first flotation screening), it was found that a particle size group of 350 µm or more was hardly seen in the Jobu ship's float, but still exists in the Jobu ship's residue. However, before performing the refining floatation (second floatation), the residues of the crude floatation were re-pulverized with a rod mill so that D90 was 300 μm. This eliminates the particle size group (+350㎛) that cannot be floated on the ship, and supplies the crushed product (crushed product of the remains of the shipbuilder, D90 = 276㎛) with an incidental degree of liberation to the refinery ship. Therefore, when floating screening was performed, the rate of removal of contaminated soil increased and the rate of removal of fluoride increased rapidly.

Therefore, in the flotation sorting process, in order to minimize the pulverization processing capacity and excessive generation of fine particles, in the first pulverization step, D90 is pulverized to 0.5 mm and put into the grandfather ship (first flotation screening) process. Mg/kg) was not satisfied, it was judged that the purification effect could be expected if D90 was regrind to 0.3mm before the refining float (second floating screening).

la. Floating screening efficiency according to the concentration of contaminated soil slurry

The rate of purification of contaminated soil at the site (throughput per unit time) is closely related to the concentration of the slurry. In general, the lower the slurry concentration, the higher the purification efficiency, but the throughput per unit time decreases. Conversely, the higher the slurry concentration, the higher the throughput per unit time, but the purification efficiency is expected to decrease.

Therefore, it is important to understand the optimum treatment amount per unit time (slurry concentration) and the purification process chart in order to determine the composition of the soil purification treatment device and the capacity of each device.

FIG. 16 is a graph showing the results of flotation of medium and low concentration contaminated soil by slurry concentration, and FIG. 17 is a graph showing the results of flotation of high concentration contaminated soil by slurry concentration. In particular, FIG. 16 is a graph showing the results of flotation selection according to an increase in slurry concentration for medium-low-concentration fluorine-contaminated soil (D90 = 543 µm) having a fluorine concentration of 499 mg/kg. 17 is a graph showing the result of flotation selection according to an increase in slurry concentration for high-concentration fluorine-contaminated soil (D90 = 552 μm) having a fluorine concentration of 1,044 mg/kg.

In FIG. 17, the removal rate of contaminated soil slightly decreases as the slurry concentration increases, so that the fluorine removal rate increases slightly. However, in terms of purification efficiency, it does not have a significant effect on the process.

Therefore, when considering the rate of purification of contaminated soil at the site in terms of stability of purification efficiency and economical efficiency, the concentration of slurry that can maximize the processing speed while sufficiently satisfying the level of concern for soil contamination in area 2 (F 400 mg/kg) is 30. % Was judged appropriate.

hemp. result

The fluoride removal rate by floating screening (Armac-T 300g/ton) was 36.7% for medium and low concentration soils and 47.2% for high concentration soils. Therefore, medium and low concentration contaminated soils with a fluorine concentration of 550 mg/kg or less can be purified only by the Jobu-seon (first flotation screening) process, and high-concentration contaminated soils have a high fluoride removal rate, but a second flotation screening process is required.

However, in the case of purifying high-concentration fluorine-contaminated soil, in order to minimize the pulverization treatment capacity and excessive generation of fine particles, in the first pulverization process, the D90 is pulverized so that 0.5 mm is put into the shipbuilding (first flotation screening) process, and the shipbuilding process In the case where the concern criterion for area 2 (400 mg/kg) is not satisfied, the purification effect that satisfies the concern criterion can be expected if the D90 is re-grinded to 0.3 mm before the refining barge (second floating screening).

As described above, according to the present invention, by using the difference in hydrophobicity-hydrophilicity, which is the physicochemical surface property of particles containing and without fluorine contaminants, specific contaminants such as fluorine in the soil are attached to the air bubbles. It can be floated and sorted.

Although the above has been described with reference to Examples, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention described in the following claims. You can understand.

T-201: input hopper T-202: input conveyor
T-203: Wet Crusher T-204: Wet Magnetic Separator
CT-201: sulfuric acid storage tank CP-201: sulfuric acid injection pump
CT-202: water catcher storage tank CP-202: water catcher injection pump
CT-203: foaming agent storage tank CP-203: foaming agent injection pump
T-205A/B: Float sorting conditioner T-206: Float sorting machine
T-206-1: Float sorter transfer tank T-208: Intermediate transfer reservoir
CT-204: neutralizing agent storage tank T-209: grit site
T-210: coagulation tank CT-205: coagulant storage tank
T-211: Settling tank T-212: Sludge storage tank
T-213: collection tank scum tank T-214: process water storage tank
T-215: Make-up water storage tank T-216A, T-216B: 1st and 2nd filter press
T-217: wet cleaning device T-218: compressor
110: hydrogen ion concentration control unit 120: water catcher stirring tank
130: agitating tank made of foam 140: floating material recovery unit
150: filtration-drying unit 160: calculating unit

Claims (10)

(i) adding a fluorine-contaminated soil slurry prepared in a predetermined particle size group to a floating screening cell equipped with an air flow controller and adjusting the pH to 3.5±0.2;
(ii) stirring while adding to the resultant of step (i) a catching agent, which is a flotation screening reagent, which is adsorbed to the surface of mica as a source of fluorine contamination and changes its surface to hydrophobicity to facilitate attachment to air bubbles;
(iii) stirring while adding a foaming agent after the first reaction time has elapsed in the resultant of step (ii);
(iv) injecting compressed air and recovering the suspended matter after the second reaction time has elapsed in the resultant product of step (iii);
(v) filtering and drying the recovered suspended matter and the soil slurry remaining in the flotation cell after completion of the flotation screening after the passage of the flotation time has elapsed; And
(vi) including the step of calculating the yield of floating product (Yeld of floating product, Y _F , or contaminated soil removal rate) and the removal rate of fluorine (Removal of fluoride by floation, R _m ) through weight measurement,
The yield of the floating material is,

(Where, R is calculated by the weight of the raw material (g), F is the weight of the floating material (g)),
The fluorine removal rate is,

(Where, Rr' is the F content of the raw material, Ff' is the F content of the suspension, Ss' is the F content of the residue, S is the weight of the residue (g), and r'is the F concentration in the raw material (mg/kg). , s'is the flotation screening method of fluorine-contaminated soil, characterized in that calculated by the F concentration in the residue (mg/kg)). The method of claim 1, wherein the fluorine-contaminated soil slurry of the particle size group having a diameter of 0.3 mm to 0.5 mm is treated by a rougher flotation, and the fluorine-contaminated soil slurry of the Indian group having a diameter of less than 0.3 mm is applied to the refining barge. Float screening method for fluorine-contaminated soil, characterized in that it is treated by. delete The method of claim 1, wherein the water catcher contains Armac-C or Armac-T. The method of claim 4, wherein the Armac-T is 300 g/ton. The method of claim 1, wherein the foaming agent contains AF65. The method of claim 6, wherein the AF65 is 50 g/ton. The method of claim 1, wherein the compressed air is injected at an air injection amount of 2.0 L/min. A hydrogen ion concentration control unit having a floating screening cell with an air flow rate controller attached thereto to receive a fluorine-contaminated soil slurry prepared in a predetermined particle size group and adjust the pH to 3.5±0.2;
A water catcher stirring tank for adsorbing on the surface of mica, which is a source of fluorine contamination, to change the surface to hydrophobicity and stirring while adding a catcher, which is a floating screening reagent that facilitates attachment to the air bubbles;
A foaming agent stirring tank for stirring while adding a foaming agent after the first reaction time has elapsed after the addition of the foaming agent;
A floating material recovery unit for injecting compressed air and recovering the floating material after the second reaction time has elapsed after the addition of the foaming agent;
A filtration-drying unit for filtering and drying the recovered suspended matter and the soil slurry remaining in the floatation cell after completion of the floatation after the floating time has elapsed; And
It includes a calculation unit that calculates the yield of floating product (Y _F , or contaminated soil removal rate) and the fluorine removal rate (Removal of fluoride by floation, R _m ) through weight measurement,
The yield of the floating material is,

(Where, R is calculated by the weight of the raw material (g), F is the weight of the floating material (g)),
The fluorine removal rate is,

(Where, Rr' is the F content of the raw material, Ff' is the F content of the suspension, Ss' is the F content of the residue, S is the weight of the residue (g), and r'is the F concentration in the raw material (mg/kg). , s'is a fluorine-contaminated soil flotation screening system, characterized in that calculated by the F concentration in the residue (mg/kg)).
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