KR101709716B1 - Method for recycling Heavy Metals Contaminated Particles - Google Patents

Abstract

The present invention relates to a floatation method for recycling of soil contaminated with arsenic. The present invention includes: a step of preparing the soil contaminated with arsenic; a surface grinding step of grinding the surface of the prepared soil; a pulp formation step of forming pulp by suspending the ground soil in a solution; a first floatation step of performing floatation after adding to the pulp a collector for particle surface hydrophobization, an activator for activating an oxidation reaction of the collector, a foaming agent for bubble generation and floating, and a carrier for coagulation and cross-linking of hydrophobic particles; and a secondary floatation step of performing floatation after adding the collector, the activator, the foaming agent, and the carrier to rougher tailings recovered by the first floatation.

Description

METHOD FOR RECYCLING HEAVY METAL CONTAMINATED PARTICLES

The present invention relates to a floating sorting method for recycling particles contaminated with a heavy metal, and more particularly, to a floating sorting process for increasing a heavy metal efficiency by adding a carrier of a hydrocarbon-based material to a contaminated particle material solution .

Conventional physicochemical methods for treating heavy metals in contaminated particles, such as soil, include solidification / stabilization methods and soil washing methods. The solidification / stabilization method is a technique of mixing pollutant soil with additives such as cement, lime and the like to reduce the mobility of pollutants or change them into a harmless form. However, this treatment method is not very effective when the water content of the soil is over 50% and organic pollution exists during the treatment. Also, it costs a lot of reagents and additives, and it is hard to recycle the soil. Soil washing method is a technique to reduce the volume of contaminated soil by separating into fine soil and liquid using washing liquid and mechanical frictional force. However, this treatment method is affected by the permeability of the soil, and it has a disadvantage that it is very difficult to select and manufacture the cleaning agent to be applied to the composite pollutant. Flotation screening, which can overcome these shortcomings, has recently been widely used.

Floating sorting refers to the formation of fine bubbles in the pulp in which fine particles are suspended to float the mineral particles with hydrophobic surfaces and the mineral particles with hydrophilic surfaces remain in the liquid solution Is a physicochemical sorting method that utilizes the principle of the discharge of water. Reverse flotation among flotation sorting methods is a flotation sorting method which is recently used for waste treatment, wastewater treatment and contaminated soil purification by floating the dunnage material and removing the target material in the slurry.

It is very important to control the size of soil particles, the concentration of light, the flotation reagents and the pH of the flotation water in order to efficiently remove heavy metals in contaminated soil using flotation screening.

On the other hand, the soil around the smelter contains various heavy metals, and it is necessary to refine it. Especially, the content of arsenic in heavy metals exceeds the criterion of pollution concern, so it is urgent to remove arsenic from the soil. Korean Patent Publication No. 10-0541464 discloses a method for purifying heavy metals in soil using flotation screening technology, but does not provide a flotation screening process capable of efficiently removing arsenic.

Accordingly, an object of the present invention is to provide an optimum process of floating sorting for removing heavy metals effectively from contaminated fine particles.

Also, the float-sorting process according to the present invention can reduce the concentration of heavy metals such as arsenic to less than 25 ppm and reuse the soil.

On the other hand, other unspecified purposes of the present invention will be further considered within the scope of the following detailed description and easily deduced from the effects thereof.

In order to solve the above-mentioned problems, the present invention provides a method of manufacturing a semiconductor device, comprising: preparing a particulate material contaminated with heavy metal; A particle liquid forming step of suspending the particle material in a solution to form a particle liquid; Adding a trapping agent to hydrophilize the particle surface to the particle liquid; Adding the carrier to the first additive particle solution to cause the particles to aggregate first, and then performing a first float selection; Adding a trapping agent to the particle liquid recovered by the first floating particle; Wherein the weight ratio of the carrier to the catcher is in the range of 1: 1 to 2: 1, and wherein the weight ratio of the carrier to the catcher is from 1: 1 to 2: : ≪ RTI ID = 0.0 > 1. ≪ / RTI >

The heavy metal may be at least one selected from the group consisting of arsenic, copper, zinc and lead.

The catching agent is selected from the group consisting of sodium amyl xanthate, potassium ethyl xanthate (PAX), sodium ethyl xanthate, sodium isopropyl xanthate, sodium isobutyl Sodium isobutyl xanthate, and Potassium amyl xanthate.

The particles may be a soil having a particle size distribution of 150 mu m or less.

The carrier may be polyethylene glycol (PEG (diesel)).

The carrier used in the secondary float sorting may be a hydrocarbon compound having a smaller molecular weight than the carrier used in the primary float sorting.

The flotation screening method according to the present invention is not only economical, but also can float the soil of fine particles contaminated with arsenic most efficiently, especially by recycling heavy metal contaminated soil (ie, fine soil) of a certain size or less It becomes possible to recycle heavy metal contaminated soil for a whole range of particle sizes. In addition, according to the floating sorting method of the present invention, since the heavy metal concentration of fine particles such as soil contaminated with heavy metals such as arsenic can be lowered to a level lower than a desired level, the soil contaminated with heavy metals can be reused, And it is possible to achieve economical benefit by expanding resources.

On the other hand, even if the effects are not explicitly mentioned here, the effect described in the following specification, which is expected by the technical features of the present invention, and its potential effects are treated as described in the specification of the present invention.

FIG. 1 is a step diagram of a flotation selection method for recycling soil contaminated with arsenic according to the present invention.
FIG. 2 is a result of X-ray diffraction analysis performed to confirm the kind of minerals contained in soil samples according to an embodiment of the present invention.
3 is a photograph of a floating sorting device of the Denver Sub A type which is the floating sorting device used in the embodiment of the present invention.
FIG. 4 is a graph showing the quality and removal efficiency of arsenic after the flotation test by adding PEG as a carrier. FIG.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. And certain features shown in the drawings are to be enlarged or reduced or simplified for ease of explanation, and the drawings and their components are not necessarily drawn to scale. However, those skilled in the art will readily understand these details.

The present invention uses flotation screening technology to purify soil which is a particulate material contaminated with heavy metals such as arsenic around a smelter to less than 25 ppm of arsenic concentration criterion according to Korean soil pollution standards, In order to increase the particle sorting efficiency of fine particles (38 ㎛ or less), a catching agent for hydrophobizing the particle surface is first added to the suspension of particles. After a lapse of a certain period of time, a hydrocarbon-based carrier having a hydrophobic characteristic is introduced into the particle liquid of the particle-surface-hydrophobic particle to crosslink the particles. That is, the present invention uses a separate carrier for crosslinking the hydrophobized particles after hydrophobicization of the hydrophilic particles, thereby making the fine particles having high contamination degree suitable for float sorting. As a result, Float sorting becomes possible. Particularly, the present invention improves the probability of contact between fine particles and carriers by shortening the length (molecular weight) of the carrier in each floating step.

Although the soil is exemplified as a particle material in the following embodiments, the scope of the present invention is not limited thereto, and the scope of the present invention can be applied to any material made of fine particles.

The floating sorting method for recycling contaminated particles comprises: preparing a particle material contaminated with a heavy metal; A particle liquid forming step of suspending the particle material in a solution to form a particle liquid; Adding a trapping agent to hydrophilize the particle surface to the particle liquid; Adding the carrier to the first additive particle solution to cause the particles to aggregate first, and then performing a first float selection; Adding a trapping agent to the particle liquid recovered by the first floating particle; And adding a fourth carrier to the third added particle liquid to cause the hydrophobizing agent to second flocculate the particles, followed by a second float sorting step.

In one embodiment of the present invention, the weight ratio of the carrier to the catcher is 1: 1 to 2: 1. Particularly, when the carrier is excessive relative to the catching agent, the arsenic removal efficiency due to the actual aggregation deteriorates, which will be described in detail below.

In another embodiment of the present invention, an activator for activating the oxidation reaction of the captive agent, a foaming agent for generating and suspending bubbles are first added together with a capturing agent, and after a certain period of time, the carrier is added again for floating. Particularly, the present inventors have found that the decontamination effect of the soil is greatly increased when the catching agent and the carrier are sequentially added in the same manner to the recovered particle solution in general.

In one embodiment of the present invention, the heavy metal may be at least one selected from the group consisting of arsenic, copper, zinc and lead, and the particulate matter may be a soil.

If the heavy metal is arsenic and the particulate material is a soil, the method comprises: preparing a particulate material contaminated with heavy metals as in Figure 1; A particle liquid forming step of suspending the particle material in a solution to form a particle liquid; Adding a trapping agent to hydrophilize the particle surface to the particle liquid; Adding the carrier to the first additive particle solution to cause the particles to aggregate first, and then performing a first float selection; Adding a trapping agent to the particle liquid recovered by the first floating particle; And adding a carrier to the third added particle solution to cause the second aggregation of the particles, followed by a second float sorting step. Hereinafter, the present invention will be described on the basis of arsenic and soil, The scope of the invention is not limited thereto.

In an embodiment of the present invention, the soil containing arsenic (As) around the smelter is selected in the step of preparing the soil contaminated with arsenic, and the selected soil is sieved, So as to have an appropriate particle size distribution. In order to broaden the recycling range of the soil, the present invention uses a floating sorting technique rather than a soil washing method, and thus the particle size range is relatively broad. The particle size distribution is preferably 150 탆 or less using a ball mill or the like, but is not limited thereto.

The step of forming the optical fluid according to the present invention is a step of suspending the pulverized soil in a solution to form a light liquid. The pulverized soil is mixed with water and placed in a cell of a floating separator, do. The concentration of the optical fluids is preferably 10 to 20%, but is not limited thereto.

In the first floatation step (rougher flotation) according to the present invention, a carrier, an activator and a foaming agent are first added to the optical fluid, and after a certain period of time, a carrier is added, followed by floating. A bubble-contact type flotation device can be used as a flotation screening device according to an embodiment of the present invention. The pH is adjusted by using hydrochloric acid while stirring in a flotation screening cell for a predetermined time after the light is introduced into the flotation device. The pH is preferably in the range of 3.5 to 4.5. After the appropriate pH adjustment, the catching agent, the activator and the carrier are put in, and finally the foaming agent is mixed and agitated, followed by float sorting for a certain period of time.

The collector is a reagent which makes the mineral surface hydrophobic. In the present invention, sodium amyl xanthate, potassium ethyl xanthate (PAX), sodium ethyl manganate It may be any one selected from sodium ethyl xanthate, sodium isopropyl xanthate, sodium isobutyl xanthate and potassium amyl xanthate (PAX).

If the addition amount of the captive agent is too high, it may be adsorbed on the surface of the mineral particles by supersaturation, and the hydrophobic property of the particles may be weakened by decreasing the ratio of the hydrocarbon group or the nonpolar group in the light liquid. / ton to 220 g / ton. Particularly, in one embodiment of the present invention, the weight ratio of the carrier to the catcher is 1: 1 to 1: 2. If the carrier is smaller than the above range, the effect of intergranular coagulation due to the crosslinking effect by the carrier is deteriorated. The aggregation effect of the hydrophobic particles is deteriorated.

In the present invention, sodium sulfate (Na ₂ S) and copper sulfate (CuSO ₄ ) are used as the active agent, and the active agent actively promotes the oxidation reaction on the mineral surface of the catcher. Were used. The addition amount is preferably from 180 g / ton to 220 g / ton, but is not limited thereto.

The carrier serves as a bridge for aggregating the hydrophobic particles in the floating sorting system. As can be seen from the embodiments of the present invention to be described below, it can be seen that the concentration of arsenic in particulate particles contaminated with arsenic, especially in the particle size range of less than 38 mu m, is significantly higher than that in other particle size ranges .

On the other hand, it is generally known that it is difficult to select floating particles in the case of fine particles smaller than 38 탆. In the present invention, by introducing the carriers, these particle particles are agglomerated, and accordingly, they can be adjusted to particle sizes suitable for float sorting.

In an embodiment of the present invention, the carrier may be polyethylene glycol (PEG) or polyethylene oxide (PEO) as a hydrocarbon-based material. Particularly, in the case of secondary float sorting, a carrier having a small molecular weight . That is, when the chain length of the carrier is short, the possibility of contact with the particles becomes high. Therefore, it is preferable to remove the carrier after the primary floating separation, in which the number of the fine particles is increased, to a short chain length. However, in the case of primary float sorting, particles having larger particle sizes may exist, so that a length sufficient to hold these particles is required.

In one embodiment of the present invention, the amount of the carrier added is preferably from 180 g / ton to 220 g / ton, but is not limited thereto. Particularly, in the present invention, it is preferable that the carrier is different in the primary floating sorting and the secondary floating sorting, and the chain length of the hydrocarbon-based material used in the primary floating sorting is preferably set as compared with the secondary floating sorting. In one embodiment of the present invention, the molecular weight of PEG was 2500 in primary float selection, while 1000 PEG was used in secondary float selection.

2 is a schematic diagram showing the mechanism of the carrier according to an embodiment of the present invention. FIG. 2A shows a process in which PAX is adsorbed on a mineral surface to be hydrophobized according to an embodiment of the present invention. In FIG. 2B, the carrier coagulates the fine particles to enable particle size control suitable for float sorting .

The frother is a kind of flotation reagent used in flotation sorting. It is a reagent used for facilitating the generation and dispersion of bubbles and generating stable bubbles. The present invention relates to a reagent for the production of methyl isocarbinol (MIBC, 4-methyl-2-pentanol), dowfloat-250 (DF-250)

If the added amount of foaming agent is too much, there is a fear that the quality of the product is reduced and the screening efficiency is decreased. If the amount of the foaming agent is too small, the surfactant function of lowering the surface tension of the optical fluid is not performed well. There is a possibility that the recovery rate may decrease. In view of this, the amount of the foaming agent added is preferably 700 mL / ton to 800 mL / ton.

The scavenging flotation (scavenging flotation) according to the present invention may be performed by first adding a catcher, an activator and a foaming agent to rougher tailings recovered by the first floatation (rougher flotation) After the carrier has been added to the carrier, the carrier is once again subjected to flotation under the same conditions. The scavenger tailings obtained by the second flotation can be used as the recycled soil. In one embodiment of the present invention, the carbon number (chain length) of the carrier used in the secondary float sorting is preferably longer than the carrier used in the primary float sorting.

On the other hand, by repeating the third and fourth float sorting, the removal efficiency of the soil contaminated with arsenic is increased, but the first and second float sorting are carried out considering the economic aspect of the float sorting process Most preferred.

Hereinafter, the present invention will be described in more detail by way of specific examples. It will be apparent to those skilled in the art that the present invention is not limited by the following examples, but can be variously modified or changed within the spirit and scope of the present invention.

Example  One

1. Selection of sample

In the examples of the present invention, soil around the Janghang smelter containing arsenic was selected.

2. Evaluation of Physical Properties of Samples

Inductively Coupled Plasma (ICP) analysis was performed to determine the characteristics of the soil (arsenic content contained in the soil) through quantitative analysis of the elements in the soil of the Janghwa smelter used in the examples of the present invention . Three samples were each measured to obtain an average value. As a result of the ICP measurement, it was confirmed that the As (As) content was about 332 ppm, which is more than 25 ppm.

X-ray diffraction (XRD) analysis was performed to confirm the kinds of minerals contained in the samples used in the examples of the present invention.

FIG. 2 is a graph showing the results of X-ray diffraction analysis conducted to confirm the kind of minerals contained in a soil sample according to an embodiment of the present invention. 3, the presence of quartz (SiO ₂ ), arsenopyrite (FeAsS), and arsenic pentoxide (As ₂ O ₅ , arsenic trioxide, As ₄ O ₆ ) can be confirmed.

3. Flotation screening method

The soil sample used in one embodiment of the present invention is the soil around the Janghang smelter and has a particle size distribution of 150 μm or less. The soil was ground using a ball-mill.

The soil samples were dried at 80 ^° C and 120 g samples were used for each flotation test.

As a result of checking the arsenic concentration according to the particle size of the sample (Table 1), it was found that the smaller the particle size, the higher the arsenic concentration. Particularly, the concentration was significantly higher at less than 38 탆.

The soil samples were mixed with water and placed in a cell of a floating sorting machine and stirred to form a 12% concentration light solution.

The floating sorting apparatus used in the embodiment of the present invention was a Denver Sub-A type flotation sorter of Lab-scale, which is a bubble-contacting flotation apparatus, and a 1 L flotation cell was used (FIG. Flotation screening experiments were conducted with three carriers to determine the maximum arsenic removal efficiency. Catcher agent is potassium amyl xanthate (PAX), active agent is sodium sulfide (Na ₂ S) and copper sulfate (CuSO _4), foaming agent is dowfloat-250 (DF-250) , the carrier was experimented with PEG, experiments at pH 4 .

In one embodiment of the present invention, it is preferable to use PEG having a chain length (small molecular weight) shorter than that of PEG for selection of primary floating, and it is preferable to use PEG having a shorter chain length Which will be described in more detail below.

The amount of reagent used was fixed at 200 g / ton carrier, activator, carrier and 750 mL / ton foaming agent.

As the condition giving time, the sample was adjusted to pH 4 with 1 N hydrochloric acid while stirring in a floating sorting cell for 3 minutes. After that, stirring was performed 10 minutes after the addition of Na ₂ S, 10 minutes after the addition of CuSO ₄ , 5 minutes after the PAX injection, 5 minutes after the carrier injection, and finally 3 minutes after the addition of DF-250. Min.

Secondary scavenging flotation was performed under the same conditions (carrier only) with rougher tailings after the first rough floatation. The scavenger concentrate (conc., Recovered by secondary flotation screening), the rougher concentrate (middling), the scavenger tailings, the tail, the secondary Precipitate recovered by float sorting) was dehydrated using a filter, and dried at 80 degrees for about 12 hours to measure its weight. By-products and sediments were dried and weighed, and then the degree of decontamination and arsenic removal efficiency were determined by ICP analysis, respectively.

4. Results

FIG. 4 is a graph showing the quality and the arsenic removal efficiency after floating test.

4, it can be seen that the removal efficiency was high by adding PEG and the second floating sort surely. In the embodiment of the present invention, the cumulative arsenic removal efficiency was about 97.8%, and the residual arsenic concentration Was 16.57 ppm.

Example  2

Table 2 below shows the results of comparative experiments with the case of reversing the molecular weight conditions of the carrier (Comparative Example, first low molecular weight, second high molecular weight).

Comparative Example Example Removal efficiency 96.2% 99.8

Referring to the above results, it can be seen that when the carrier liquid having a relatively short chain length is used, the effect of removing the contaminant is maximized because the fine particles are increased in the case of the recovered particle liquid after the primary floating.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (6)

Preparing a particulate material contaminated with a heavy metal;
A particle liquid forming step of suspending the particle material in a solution to form a particle liquid;
Adding a capturing agent for hydrophobizing the particle surface of the particle liquid to the particle liquid;
Adding the carrier to the first additive particle solution to cause the particles to aggregate first, and then performing a first float selection;
Adding a trapping agent to the particle liquid recovered by the first floating particle;
Adding a carrier to the third added particle liquid to cause the second coagulation of the particles, and then performing a second float sorting step,
Wherein the weight ratio of the catcher is 1: 1 to 2: 1 for each floating step, the carrier is polyethylene glycol (PEG), and the carrier used in the second float sorting is used in the first float sorting Carrier having a molecular weight lower than that of the carrier.
The method according to claim 1,
Wherein the heavy metal is at least one selected from the group consisting of arsenic, copper, zinc, and lead.
The method according to claim 1,
The catching agent is selected from the group consisting of sodium amyl xanthate, potassium ethyl xanthate (PAX), sodium ethyl xanthate, sodium isopropyl xanthate, sodium isobutyl Sodium isobutyl xanthate, and potassium amyl xanthate. The method of recycling heavy metal contaminated particles according to claim 1, wherein the isobutyl xanthate is selected from the group consisting of sodium isobutyl xanthate and potassium amyl xanthate.
The method according to claim 1,
Wherein the particle is a soil having a particle size distribution of 150 mu m or less.
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