KR102236811B1 - Recovering method of poly methyl methacrylate and poly aluminum sulfate from waste scagliola - Google Patents

Abstract

The present invention relates to a recovering method of poly methyl methacrylate and poly aluminum sulfate from waste scagliola, and more particularly, to a recovering method of poly methyl methacrylate and poly aluminum sulfate from waste scagliola, in which waste artificial marble powder is pre-treated with sodium stearate mixed with sodium hydroxide and stearic acid to disperse particle sizes of the waste artificial marble powder into small sizes, thereby increasing the reaction surface area with sulfuric acid; reaction heat with sulfuric acid in the initial reaction is increased as the content of the alkali agent is increased by the sodium stearate to improve the responsiveness, achieve excellent recovery efficiency even when a low concentration of waste sulfuric acid is used, to reduce production costs and improve economic feasibility; and aluminum polysulfate is efficient recovered by reacting aluminum hydroxide with sulfuric acid under high pressure and high temperature conditions.

Description

Recovering method of poly methyl methacrylate and poly aluminum sulfate from waste scagliola}

The present invention is a process of pretreating waste artificial marble powder with sodium stearate in which sodium hydroxide and stearic acid are mixed to reduce the particle size of waste artificial marble powder, and aluminum hydroxide reacts with sulfuric acid under conditions of high pressure and high temperature to produce aluminum polysulfate. By including a process to be liquefied and separated into, unlike the prior art using sulfuric acid with a high concentration (sulfuric acid content of 98% by weight), waste artificial marble powder is converted to waste sulfuric acid with a low concentration (sulfuric acid content of 50 to 70% by weight). The present invention relates to a method for separating and recovering aluminum polysulfate and PMMA from waste artificial marble so that the recovery efficiency of aluminum polysulfate and PMMA can be improved even when reacted.

The use of artificial marble is increasing rapidly as buildings are advanced in recent years. The artificial marble market is showing remarkable growth thanks to the expansion of the domestic market in line with the trend of luxury interiors in apartments these days.

Artificial marble is used for floor finishing materials (lobby, sauna, floor, material separator, etc.), counters and desks (hotel and office lobby, etc.), wall and column finishing materials (elevator walls, office partitions, store fronts, public buildings, etc.), bathtub finishing, The use of shower booths, window seals, kitchen walls, etc. continues to increase.

Artificial marble, which is currently widely used in Korea, is mainly manufactured by mixing aluminum hydroxide and polymethyl methacrylate (Poly Methyl Methacrylate, hereinafter referred to as'PMMA') as main components, and its composition is about 30-40% by weight of PMMA. , It consists of about 50-60% by weight of inorganic filler and a small amount of other additives (antifoam, dispersant, calcium hydroxide, initiator, etc.).

Among the above constituents, the aluminum compound, which is an inorganic filler, has properties that improve the strength and abrasion resistance of artificial marble, as well as good color development, so aluminum hydroxide is used as an inorganic filler in most of the artificial marble products produced in Korea.

In addition, artificial marble having the above components is processed to the required size after manufacture and used as a top plate for sinks or other goods. In the process of processing, a large amount of scrap and dust are generated as by-products, such as scrap and dust. Since silver cannot be used for other commercialization, most of them are simply landfilled or disposed of by incineration, but not only the securing of landfill costs and the ground after landfilling is unstable, and secondary soil pollution is caused, and in case of incineration, harmful gases or odors It causes pollution of the air environment by the generation of and the generation of carbon dioxide.

Therefore, as a way to solve the above problems, as a method for treating waste artificial marble or artificial marble by-products has been recently developed, and looking at the contents of the patent application, as shown in Fig. 1 in Patent Document 1, scrap of artificial marble After crushing (P1) and then pyrolysis (P2), the gas component generated in this process is supplied and condensed with a condenser to liquefy, and the condensed liquid phase is separated by a centrifuge and an oil-water separator to remove water and impurities. ), and sintering (P4) the remaining char residue to recover (P6) alumina and pulverize the waste artificial marble in the pretreatment step (S1) as shown in Fig.2 in Patent Document 2 Then, by performing thermal decomposition treatment (S2), the separated gasified resin and additive raw materials are repeatedly condensed and purified to remove impurities and additives, and regenerated (S3) with purified pure resin, and classified in the pyrolysis treatment step. A method for treating waste artificial marble is known, characterized in that the powdered filler and additive raw materials are calcined and heated at a high temperature to remove impurities and additives, and the calcined filler is regenerated (S4).

In the case of the above patents, artificial marble scraps and dust are pyrolyzed to separate volatile MMA and purified to recover pure MMA, and trace impurities are burned and removed by completely burning the residues completed by pyrolysis through a kiln. The resulting pure alumina is received, and the alumina produced at this time is carbonized by combustion, and the color appears black. In this carbonization, organic matter remaining in the first MMA recovery process is carbonized through a high-temperature sintering process, which causes serious problems in recycling of alumina as well as thermal decomposition at a high temperature of 200 to 700°C in the process of recovering MMA. Accordingly, in this process, MMA, an organic compound, is partially burned and lost due to high-temperature heat. Also, in the firing process for recovering alumina, a lot of energy is required due to high-temperature pyrolysis, so there is a problem of low economical efficiency.

In addition, aluminum, which is an inorganic filler, is a material that does not volatilize, and in the process of heating to recover MMA, some of the moisture is discharged and converted into aluminum oxide (alumina) components. In this process, as shown in Formula 1 below, unnecessary energy loss and a lot of moisture occur. Difficulties arise because moisture is mixed in the recycling process of MMA.

Al(OH) ₃ → Al ₂ O ₃ + H ₂ O (Chemical Formula 1)

In addition, as a technology for separating and recovering organic substances of acrylic resin components from waste artificial marble, in Patent Document 3 and Patent Document 4, silica is used as an inorganic filler used for construction materials such as bathroom materials, kitchen counter materials, furniture materials, interior materials, and exterior materials. Hydrolyzed the crosslinked part of the thermosetting acrylic resin and silica by using a subcritical fluid, which is an organic solvent such as water, alcohol, and ether, of acrylic artificial marble, which is a plastic waste containing a thermosetting acrylic resin containing Although a method of separating and recovering organic matter from one decomposition product is known, in the case of water, which is a subcritical fluid used in the above patent, water near room temperature is raised to about 180 to 280°C, which is a subcritical state, and 15 In order to maintain the high pressure before and after MPa, not only requires a separate high pressure critical facility to form a separate subcritical state, but also the utilization efficiency of the subcritical fluid is not high at the level of technology so far. To put it into practical use, there are difficulties that must solve many problems.

In order to solve this problem, Patent Document 5 provides a method for recovering aluminum compounds and MMA from waste artificial marble, comprising: a pretreatment step (P100) for selecting uniform powder of waste artificial marble; A slurry forming process (P200) in which water is mixed with the selected waste artificial marble powder to have fluidity; An aluminum compound reaction step (P300) in which an acid compound is mixed with the slurry formed in the above step and then heated to react the aluminum component contained in the waste artificial marble powder with the acid compound; A solid-liquid separation step (P400) for separating the aluminum compound and PMMA in a solid state using a solid-liquid separation device was proposed for recovering aluminum compounds and MMA by acid treatment from waste artificial marble.

That is, Patent Document 5 does not perform high-temperature thermal decomposition when recovering liquid aluminum compounds from waste artificial marble or artificial marble scrap or powder by acid treatment, so that liquid aluminum compounds can be recovered using a small amount of energy. In addition, as the conventional method pyrolyzes the waste artificial marble at a high temperature of 200 to 700°C, the organic compound PMMA is partially burned and lost by high temperature heat, thereby reducing the recovery rate of MMA. It was intended to improve the recovery rate of MMA because no PMMA was lost by treatment, and also, primarily by separating the liquid aluminum compound from the waste artificial marble and then recovering the PMMA, thereby improving the MMA recovery rate compared to energy input.

However, in the case of Patent Document 5, a high-concentration sulfuric acid having a sulfuric acid content of about 98% by weight should be used. The reason is to raise the reaction temperature by reacting initial water with high concentration sulfuric acid, and then to react with aluminum hydroxide contained in the artificial marble powder.

That is, in the case of Patent Document 5, when waste sulfuric acid (low concentration sulfuric acid having a sulfuric acid content of about 70% by weight) is used, the reaction heat causing initial reaction with water or aluminum hydroxide is insufficient, or aluminum hydroxide surrounded by PMMA does not react with sulfuric acid. There is a problem in that the production efficiency of aluminum sulfate is lowered.

Moreover, there is a need to recover aluminum hydroxide, which is economical as the production cost is lower than that of the existing process, and is a useful resource in waste, as a fluorine and phosphorus treatment agent, as an inorganic polysulfate used as an inorganic coagulant that agglomerates colloidal particles in water. In the case of Patent Document 5, there is a problem in that the aluminum polysulfate cannot be recovered.

Patent Document 1: Republic of Korea Patent Publication No. 10-0891378 "Recovery method of MMA and alumina from waste artificial marble" Patent Document 2: Republic of Korea Patent Publication No. 10-0917105 "Waste artificial marble pyrolysis treatment apparatus and waste artificial marble treatment method using the same" Patent Document 3: Japanese Laid-Open Patent Publication No. 2006-206638 "Decomposition method of artificial marble" Patent Document 4: Japanese Laid-Open Patent Publication No. 2008-184475 "Method of decomposing and recovering plastics" Patent Document 5: Korean Registered Patent Publication No. 10-0982728 "Method for recovering aluminum compounds and MMA from waste artificial marble by acid treatment"

The present invention is to solve the above problems, and it is possible to improve the recovery efficiency of aluminum polysulfate and PMMA even when the waste artificial marble powder is reacted with waste sulfuric acid having a low concentration (sulfuric acid content 50 to 70% by weight). Make it an assignment.

More specifically, in the present invention, by pretreating the waste artificial marble powder with sodium stearate in which sodium hydroxide and stearic acid are mixed, the particle size of the waste artificial marble powder is dispersed to a small size to increase the reaction surface area with sulfuric acid, and an alkali agent by the sodium stearate. As the content of is increased, the heat of reaction with sulfuric acid in the initial reaction is increased to improve its reactivity, and even when a low concentration of waste sulfuric acid is used, the production cost is reduced and economical efficiency is also improved by realizing excellent recovery efficiency. Make it an assignment.

In addition, it is an object of the present invention to allow aluminum hydroxide to react with sulfuric acid to be liquefied and separated into aluminum polysulfate under high pressure and high temperature conditions.

The present invention provides a method for recovering aluminum polysulfate and PMMA from waste artificial marble, comprising: mixing water to waste artificial marble powder and adding sodium hydroxide and stearic acid to disperse and slurry the waste artificial marble powder particles (S100); Adding and reacting the slurry to waste sulfuric acid to prepare aluminum polysulfate, and then adding diluted water to prepare liquid aluminum polysulfate (S200); And separating and recovering the liquid aluminum polysulfate and PMMA, respectively, using a solid-liquid separation device (S300); As a solution.

Here, the waste sulfuric acid is preferably sulfuric acid having a concentration of 50 to 70% by weight of sulfuric acid.

Meanwhile, in the step S100, sodium hydroxide and stearic acid are added to the waste artificial marble powder having a particle size of 90 to 110 μm to disperse the particle size to 5 to 15 μm and make a slurry.

And in the step S200, when the waste sulfuric acid and the slurry are reacted, it is preferable to react for 2 to 3 hours at a ^{pressure of 5 to 7 kg/cm 2 and a temperature of 130 to 200°C.}

According to the present invention, the waste artificial marble powder is pretreated with sodium stearate in which sodium hydroxide and stearic acid are mixed, so that it is possible to use a low concentration of sulfuric acid and have a recovery efficiency equal to or higher than that of the example of using a high concentration of sulfuric acid. This is reduced to have an effect of improving economical efficiency. In addition, aluminum hydroxide reacts with sulfuric acid under high pressure and high temperature conditions to efficiently recover aluminum polysulfate.

More specifically, the present invention recovers aluminum polysulfate (PAS) produced by reacting waste artificial marble powder and process sludge and sulfuric acid generated in the process of commercialization such as waste artificial marble in a high-pressure and high-temperature reaction vessel, and the remaining PMMA Is separated and recovered. The conventional method is a process of simply reacting aluminum hydroxide and sulfuric acid to produce liquid aluminum sulfate, which is a low molecular weight inorganic coagulant (2Al ₂ (OH) ₃ + 3H ₂ SO ₄ → 2Al ₂ (SO ₄ ) ₃ + 6H ₂ O). . The conventional method is to prepare a slurry by simply adding artificial marble dust to water without worrying about raw materials such as artificial marble dust, and dissolving aluminum hydroxide by adding sulfuric acid, so that the aluminum hydroxide surrounded by PMMA does not dissolve but remains in PMMA. It acts as a factor that increases the energy cost in the pyrolysis process. In the present invention, in the process of preparing a slurry by mixing artificial marble waste and water, sodium hydroxide and a dispersant (stearic acid, Stearic Acid, CH ₃ (CH ₂ ) ₁₆ COOH) are mixed to increase the recovery rate of aluminum hydroxide in the subsequent reaction process. Sodium stearate (CH ₃ (CH ₂ ) ₁₆ COONa) is prepared to efficiently disperse the particles, and then through high-pressure and high-temperature reactions, polyaluminium sulfate, a high-molecular inorganic coagulant (Poly Aluminum Sulfate: Al ₂ (OH)n( SO ₄ ) ₃ -n/2]m]. Polysulfate aluminum (PAS) with a basicity of 30 to 45% for use as an inorganic coagulant that agglomerates colloidal particles in water, as a fluorine and phosphorus treatment agent for aluminum hydroxide, which is an economical and useful resource in waste. To be recovered. Under the conditions of high pressure and high temperature, aluminum hydroxide reacts with sulfuric acid to be liquefied into aluminum polysulfate (PAS) and separated. The existing patented aluminum sulfate is a simple low-molecular inorganic coagulant that does not have basicity through an acid-alkali reaction. It is an eco-friendly construction method that recovers PMMA, an acid-insoluble component, by solid-liquid separation using a filter press, and increases the recovery rate of MMA from the recovered PMMA.

On the other hand, in the conventional process of producing liquid aluminum sulfate by reacting with sulfuric acid without going through the usual pretreatment process, the recovery rate of aluminum hydroxide is around 70 to 80%, and aluminum hydroxide remains. The recovery rate is also around 50%. The pretreatment process is unevenly agglomerated by treating 0.1 to 10.0 wt% of sodium hydroxide [NaOH] and 0.01 to 3.0 wt% of dispersant (stearic acid). To prepare a suspension that does not precipitate well in the liquid by dispersing with sulfuric acid, the reaction surface area with sulfuric acid and sodium hydroxide are added to increase the content of the alkali agent to cause a reaction under high pressure and high temperature conditions, and the heat of reaction with sulfuric acid in the initial reaction By increasing the reactivity, the recovery efficiency of aluminum hydroxide can be improved. The dispersant is usually a surfactant and is used to prepare a suspension in which a solid is dispersed in a liquid. In the existing process, the particles exist in the form of agglomerates, so precipitation occurs quickly. However, when dispersing the particles by mixing sodium polyacrylate, olefin-sodium maleate copolymer, condensed phosphate, carboxymethylcellulose, stearic acid or sodium stearate as a dispersant, precipitation does not occur quickly in the liquid, so dispersibility in water is good even at a low stirring speed. Do. In particular, when sodium stearate is produced by adding sodium hydroxide to stearic acid, it exhibits an effect as a dispersant for artificial marble dust. Increasing the recovery efficiency of aluminum hydroxide can reduce coexisting water molecules, thereby reducing energy consumption for removing non-molecules of aluminum hydroxide in the subsequent PMMA pyrolysis process, thereby increasing the efficiency in the pyrolysis process. In the above reaction process, 98% of sulfuric acid is added in a pressure reaction vessel at high pressure and high temperature, and the reaction temperature is raised by first reacting with water added to the reaction vessel, and then artificial marble powder is added to increase the reaction temperature to approximately 120 ~. Maintaining at 250 ℃, by applying a pressure of high pressure (2Kgf/cm ² ~ 8Kgf/cm ² ) to dissolve the aluminum hydroxide contained in the artificial marble to prepare aluminum polysulfate (PAS). Typically, waste sulfuric acid having a content of about 70% is difficult to use in the production of liquid aluminum sulfate due to lack of heat of reaction causing initial reaction with water or aluminum hydroxide. However, when sodium hydroxide and stearic acid are mixed to produce sodium stearate and used in the pretreatment process, the shape and size of the particles are dispersed as shown in Fig. 4, and there is a significant amount of OH-group remaining in sodium hydroxide [NaOH] after the formation of sodium stearate. Thus, it is possible to produce aluminum polysulfate (PAS) by easily reacting even at a concentration of 70% of sulfuric acid under high-pressure and high-temperature reaction conditions with an increase in the effective alkali component. In the present invention, there is no difficulty in manufacturing a product by reacting under high pressure and high temperature conditions. In this case, since all raw materials are used as waste, the cost of raw materials is not required to manufacture the product, so the cost economy of the finished product is excellent. In addition, under the above reaction conditions, the recovery rate of aluminum hydroxide contained in the artificial marble dust is 95% or more. The characteristics of poly aluminum sulfate (Al2(OH)n(SO4)3-n/2]m) prepared under these conditions are as follows. Aluminum polysulfate is a colorless to pale yellow transparent liquid and is called PAS. The general formula is [Al ₂ (OH)n(SO ₄ ) ₃ -n/2]m, n is 1≤n≥5, m is m<10, and the basicity is It is n/6 × 100%. Basicity, degree of polymerization, PH, alkali consumption, and reactivity with polyanions have similarities to those of Poly Aluminum Chloride. Poly Aluminum Sulfate has an advantage of excellent treatment performance because it forms hard and heavy aggregates with a high sedimentation rate and high adsorption activity compared to liquid aluminum sulfate. In addition, since it has a high positive charge and has crosslinking properties, it has an excellent turbidity removal effect of about 1.5 times in low turbidity and 2.0 times in high turbidity compared to aluminum sulfate. Compared to aluminum sulfate, it has excellent removal effect of silicic acid, iron, and manganese, and it has strong adsorption to turbidity, turbidity by crosslinking adsorption, and color removal ability compared to aluminum sulfate for treatment of colored water and contaminated water. In addition, since the coagulation range for PH is wide, even if the conditions of the treated water are varied, coagulation and precipitation can be stably performed. Aluminum polysulfate is more susceptible to physicochemical effects as the degree of basicity polymerization increases, and it is particularly difficult to make a highly basic solution because it becomes mechanically unstable. The agglomeration properties of PAS are the best with a solution having a basicity of about 40%, and the floc coagulation performance, defrosting effect, reduction effect of alkali preparations, proper injection rate range, and aggregation PH range are similar to those of polyaluminum chloride. In addition, aluminum polysulfate has a faster hydrolysis rate than polyaluminum chloride and has poor dilution stability, so in many cases, an undiluted solution or a double diluted solution is directly injected. As the reaction pressure increases, the basicity also increases, but the low stability of the product appears to drop sharply above 40%. The proper basicity is judged to be around 35 to 40%. By separating and recovering the remaining PMMA, it is an economical construction method that uses a small amount of energy as it does not pyrolyze aluminum hydroxide by recovering aluminum polysulfate (PSA) compounds from waste artificial marble, unlike conventional methods. In addition, it is reported that high-temperature heating of 350 ~ 450℃ is required for the remaining PMMA to be pyrolyzed. However, heating PMMA at a high temperature of 400℃ or higher may have an adverse effect of lowering the recovery rate of MMA due to pyrolysis. The carbonization phenomenon occurs and the purity decreases, and the color of the purified MMA liquid is pale yellow, and it is difficult to increase the purity. It was found that the decomposition of PMMA started slowly at 220° C. and 100% decomposition proceeded only when the temperature was increased to 400° C. Therefore, in order to accelerate the decomposition of PMMA and lower the decomposition temperature, the catalytic effect of aluminum polysulfate mixed in the PMMA residue was verified. The pyrolysis efficiency of PMMA alone was 39.932% under the same temperature condition, whereas the aluminum polysulfate 0.5-5.0% was 0.5-5.0%. In the case of mixed PMMA, there is an efficiency improvement of about 1.7 times to 68.346%.

1 is a block diagram showing a process of recovering MMA and alumina from waste artificial marble according to a conventional method.
Figure 2 is a block diagram showing a process of recovering MMA and alumina from waste artificial marble according to another conventional method
3 is a block diagram showing a process of separating and recovering aluminum polysulfate and PMMA from waste artificial marble according to the present invention.
Figure 4 is a SEM photograph comparing the particle size of waste artificial marble powder before and after sodium stearate treatment according to the present invention (500 magnification)

The present invention for achieving the above effect relates to a method for separating and recovering aluminum polysulfate and PMMA from waste artificial marble, and only parts necessary to understand the technical configuration of the present invention are described, and the description of other parts is the present invention. It should be noted that it will be omitted so as not to obscure the subject matter of the invention.

Hereinafter, a method of separating and recovering aluminum polysulfate and PMMA from waste artificial marble according to the present invention will be described in detail as follows.

According to the features of the present invention, in the case of Patent Document 5, high-concentration sulfuric acid having a sulfuric acid content of about 98% by weight should be used in order to increase the reaction temperature by reacting initial water with high-concentration sulfuric acid. By pretreating with sodium stearate mixed with stearic acid, the particle size of the waste artificial marble powder is dispersed to a small size to increase the reaction surface area with sulfuric acid, and as the content of the alkali agent is increased by the sodium stearate, the heat of reaction with sulfuric acid in the initial reaction is reduced. As the reactivity is improved by increasing it, it is possible to improve the recovery efficiency of aluminum polysulfate and PMMA even if the waste artificial marble powder is reacted with the waste sulfuric acid of low concentration.

More specifically, the present invention, as shown in Figure 3, the step of slurrying the waste artificial marble powder (S100), the liquid aluminum polysulfate production step (S200) through the reaction of the sulfuric acid and the slurry, and the liquid aluminum polysulfate It is configured to include a step (S300) of solid-liquid separation of PMMA.

The step S100 is a step of dispersing and slurrying the waste artificial marble powder particles by mixing water with the waste artificial marble powder and adding sodium hydroxide and stearic acid. As shown in FIG. 4, the waste artificial marble powder is mixed with sodium hydroxide. By pre-treatment with sodium stearate mixed with stearic acid, waste artificial marble powder having a particle size of 90 to 110 μm is dispersed in a particle size of 5 to 15 μm, and then slurry is formed.

Accordingly, the present invention increases the reaction surface area with sulfuric acid by dispersing the particle size of the waste artificial marble powder small, and increases the reaction heat with sulfuric acid in the initial reaction as the content of the alkali agent is increased by the sodium stearate. It not only improves, but also realizes excellent recovery efficiency even when low concentration of waste sulfuric acid is used.

The step S200 is a step of preparing aluminum polysulfate by adding and reacting the slurry to waste sulfuric acid, and then adding diluted water to prepare a liquid aluminum polysulfate, wherein the waste sulfuric acid contains 50 to 70% by weight of sulfuric acid. Use sulfuric acid with a concentration.

Here, the present invention improves the reactivity with sulfuric acid, as described above, and realizes excellent recovery efficiency while using low-concentration waste sulfuric acid having a sulfuric acid content of 50 to 70% by weight, thereby reducing production costs, thereby improving economic efficiency.

The step S300 is a step of separating and recovering the liquid aluminum polysulfate and PMMA using a solid-liquid separation device, and the solid-liquid separation device is a liquid polysulfuric acid using a device including a filter press or the like by a conventional method. Separate and recover aluminum and PMMA, respectively.

Hereinafter, the present invention will be described in more detail based on the following examples, but the present invention is not limited by the examples.

1. Recovery of aluminum polysulfate and PMMA from waste artificial marble

(Example 1)

21% by weight of waste artificial marble powder and 25% by weight of water are mixed, and 1% by weight of sodium hydroxide and 3% by weight of stearic acid are added to disperse the particles of the waste artificial marble (particle size: 100㎛ → 10㎛) to prepare a waste artificial marble slurry. Was prepared (S100). Then, 34 wt% of waste sulfuric acid (sulfuric acid content 70 wt%) was first added to the reaction tank, and the slurry was added to react (pressure 6 kg/cm ² , reaction at a temperature of 150° C. for 2 hours) to prepare aluminum polysulfate, A liquid aluminum polysulfate was prepared by adding 16% by weight of diluted water (S200). Then, the liquid aluminum polysulfate and PMMA were separated and recovered, respectively, using a solid-liquid separation device including the filter press (S300).

(Example 2)

18% by weight of waste artificial marble powder and 25% by weight of water were mixed, and 0.5% by weight of sodium hydroxide and 2% by weight of stearic acid were added to disperse the particles of the waste artificial marble (particle size: 90㎛ → 5㎛) to prepare a waste artificial marble slurry. Was prepared (S100). Then, 21 wt% of waste sulfuric acid (sulfuric acid content 50 wt%) was first added to the reaction tank, and the slurry was added to react (pressure 7kg/cm ² , reaction at a temperature of 130° C. for 2 hours) to prepare aluminum polysulfate, A liquid aluminum polysulfate was prepared by adding 33.5% by weight of diluted water (S200). Then, the liquid aluminum polysulfate and PMMA were separated and recovered, respectively, using a solid-liquid separation device including the filter press (S300).

(Example 3)

21% by weight of waste artificial marble powder and 21% by weight of water are mixed, and 1.5% by weight of sodium hydroxide and 3% by weight of stearic acid are added to disperse the particles of the waste artificial marble (particle size of 110㎛ → 15㎛) to prepare a waste artificial marble slurry. Was prepared (S100). Then, 29% by weight of waste sulfuric acid (sulfuric acid content 70% by weight) was first added to the reaction tank, and the slurry was added to react (pressure 5kg/cm ² , reaction at a temperature of 200°C for 3 hours) to prepare aluminum polysulfate, A liquid aluminum polysulfate was prepared by adding 24.5% by weight of diluted water (S200). Then, the liquid aluminum polysulfate and PMMA were separated and recovered, respectively, using a solid-liquid separation device including the filter press (S300).

(Comparative Example 1)

It was prepared in the same manner as in Example 1, but sodium hydroxide and stearic acid were not added, and general sulfuric acid (sulfuric acid content 98% by weight) was used.

(Comparative Example 2)

Prepared in the same manner as in Example 2, but sodium hydroxide and stearic acid were not added, and general sulfuric acid (sulfuric acid content 98% by weight) was used.

(Comparative Example 3)

Prepared in the same manner as in Example 3, but no stearic acid was added, and general sulfuric acid (sulfuric acid content 98% by weight) was used.

2. Recovery rate evaluation

The recovery rates of aluminum sulfate and PMMA were evaluated, but in the case of aluminum polysulfate, aluminum polysulfate was prepared by dissolving aluminum oxide, so the content of aluminum oxide was evaluated, and the results are shown in [Table 1] below.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Of aluminum polysulfate
Alu oxide
Minium content 8% 7% 8% 6% 7% 7% PMMA recovery rate 8% by weight 7% by weight 8% by weight 6% by weight 6% by weight 7% by weight

As shown in [Table 1], in the Example according to the present invention, unlike the Comparative Example, the waste artificial marble powder was pretreated with sodium stearate in which sodium hydroxide and stearic acid were mixed, so that a low concentration of sulfuric acid was used while a high concentration of sulfuric acid was used. It can be seen that it can have a recovery efficiency equal to or higher than that.

As described above, a method of separating and recovering aluminum polysulfate and PMMA from waste artificial marble according to a preferred embodiment of the present invention has been described in accordance with the above description and drawings, but this is only described as an example. It will be well understood by those of ordinary skill in the art that various changes and changes are possible within the scope without departing from the idea.

S100: Slurry step of waste artificial marble powder
S200: Manufacturing step of liquid aluminum polysulfate through reaction of sulfuric acid and slurry
S300: Solid-liquid separation of liquid aluminum polysulfate and PMMA

Claims (4)

In the method for recovering aluminum polysulfate and PMMA from waste artificial marble,
Mixing water with the waste artificial marble powder and adding sodium hydroxide and stearic acid to disperse and slurry the waste artificial marble powder particles (S100);
Adding and reacting the slurry to waste sulfuric acid to prepare aluminum polysulfate, and then adding diluted water to prepare liquid aluminum polysulfate (S200); And
Separating and recovering the liquid aluminum polysulfate and PMMA, respectively, using a solid-liquid separation device (S300); a method for recovering aluminum polysulfate and PMMA from waste artificial marble.
The method of claim 1,
The waste sulfuric acid,
A method for recovering aluminum polysulfate and PMMA from waste artificial marble, characterized in that it is sulfuric acid having a sulfuric acid content of 50 to 70% by weight.
The method of claim 1,
The step S100,
A method for recovering aluminum polysulfate and PMMA from waste artificial marble, characterized in that sodium hydroxide and stearic acid are added to waste artificial marble powder having a particle size of 90 to 110 μm to disperse the particle size to 5 to 15 μm and make a slurry.
The method of claim 1,
The step S200,
When the waste sulfuric acid and the slurry are reacted, a method for recovering aluminum polysulfate and PMMA from waste artificial marble, characterized in that the reaction is performed for 2 to 3 hours at a ^{pressure of 5 to 7 kg/cm 2 and a temperature of 130 to 200°C.}

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