KR20190142983A - Circulatory Method of Recovery and Recycle of Iron in Fenton Inorganic Sludge - Google Patents

Abstract

The present invention relates to a method for recovering iron included in fenton inorganic sludge and for recycling circulation, which comprises: a first step of treating organic wastewater with a fenton reagent through a fenton process and generating inorganic sludge; a second step of concentrating the inorganic sludge in a sludge thickener, then dehydrating the same, and generating dehydrated sludge; a third step of acquiring a first supernatant which is generated by mixing 20-50 wt% of the dehydrated sludge and 50-80 wt% of hydrochloric acid with respect to the total weight of the mixture; a fourth step of acquiring a second supernatant which is generated by mixing 20-50 wt% of unreacted dehydrated sludge and 50-80 wt% of the first supernatant with respect to the total weight of the mixture; a fifth step of acquiring a third supernatant which is generated by mixing 90-99 wt% of the second supernatant and 1-10 wt% of iron powder and then, reacting the same for 12-30 hours, and recovering ferrous chloride; a sixth step of conducting water treatment of organic wastewater with a fenton reagent including the third supernatant through the fenton process; and a seventh step of repeating the first step through the sixth step. Therefore, the method for recovering iron included in fenton inorganic sludge and for recycling circulation can raise cohesion of inorganic sludge and can generate dehydrated sludge from the same.

Description

Circulatory Method of Recovery and Recycle of Iron in Fenton Inorganic Sludge}

The present invention relates to a circulating method for recovering iron contained in the inorganic sludge generated in the Fenton process as ferrous chloride and recycling it to the Fenton process. More specifically, the iron used as a catalyst in the Fenton process does not disappear after completion of the reaction. In the form of iron hydroxide, the total amount of the Fenton inorganic sludge is disposed of and discarded.The Fenton inorganic sludge containing a large amount of iron is dehydrated and then reacted with hydrochloric acid as an oxidizing agent to produce a supernatant containing iron and hydrochloric acid, and the supernatant is dehydrated. By reducing iron content by reacting with sludge and then reducing iron, it is possible to expect to reduce sludge and reduce chemical usage by repeating the process of using iron waste in the wastewater treatment process. Recovery and Recycling Process of Ferric Chloride in Mineral and Fenton Inorganic Sludge It is about public law.

The Fenton process refers to a process in which a Fenton reagent including iron salt and hydrogen peroxide is mixed with wastewater of organic matter to decompose organic matter by OH radicals and water treatment.

This Fenton process is generally used in treating dye wastewater, which is an alkaline wastewater having high COD and BOD and having a temperature of 40 to 80 ° C. Various techniques for treating such dye wastewater through the Fenton process are being developed.

In general, dewatered sludge generated in a wastewater treatment plant using iron as a catalyst in the Fenton process contains a large amount of iron because most of the iron used as a catalyst is included in the sludge after the Fenton reaction. Most of these dewatered sludges are either disposed of or treated by cement recycling. However, there is a limit in the available capacity for recycling the dewatered sludge into cement, there is a problem that causes environmental pollution due to the disposal of the dewatered sludge.

The prior art of the present invention is generated after the Fenton treatment according to the technology disclosed in the applicant's Korean Patent No. 10-0168280 (name of the invention: Fenton inorganic sludge treatment method generated in the Fenton treatment process of difficult-decomposable wastewater) Inorganic sludge is reacted with sulfuric acid in the concentrated sludge stage, and the iron in the sludge is recycled by oxidizing and reducing, and then recycled by Fenton process. The efficiency was low because the reaction solution of and sulfuric acid was used as it is.

Therefore, in order to solve the problems as described above, iron salt contained in the dehydrated sludge, which is not concentrated sludge, is recovered from the inorganic sludge produced through the Fenton process through the oxidizing agent and the reducing agent and recycled back to the Fenton process, thereby reducing the amount of chemicals used. There is a need to develop a recycling and recycling method for iron that suggests treatment of dewatered sludge.

The present invention has been made in order to overcome the problems of the above technology, the main purpose is to recover the ferrous chloride by recycling the iron chloride by adding iron powder after mixing the dehydration sludge and oxidizing agent and concentration of the iron content.

Another object of the present invention is to add a flocculant to the inorganic sludge generated through the Fenton process to increase the cohesion of the inorganic sludge and to generate dewatered sludge therefrom.

Still another object of the present invention is to remove impurities from iron powder and to produce iron powder having a small particle size.

In order to achieve the above object, the recovery and recycling circulation method of iron contained in the fenton inorganic sludge according to the present invention, the first step of generating an inorganic sludge by treating the wastewater of organic matter with a fenton reagent through the Fenton process; A second step of concentrating the inorganic sludge in a concentration tank and then dehydrating to produce dewatered sludge; A third step of obtaining a primary supernatant produced by mixing 20 to 50 wt% of the dehydrated sludge and 50 to 80 wt% of hydrochloric acid based on the total weight of the mixture; A fourth step of obtaining a secondary supernatant obtained by mixing 20 to 50 wt% of unreacted dehydrated sludge with 50 to 80 wt% of the primary supernatant, based on the total weight of the mixture; A fifth to recover ferrous chloride by mixing 90 to 99% by weight of the secondary supernatant with 1 to 10% by weight of iron powder, and then reacting for 12 to 30 hours to obtain the resulting tertiary supernatant relative to the total weight of the mixture. step; A sixth step of treating the wastewater of the organic material with the Fenton reagent including the tertiary supernatant through a Fenton process; And a seventh step of repeating the first to sixth steps.

In addition, between the first step of producing the inorganic sludge and the second step of generating the dewatered sludge, the step of adding an inorganic flocculant containing iron salt and silicate as an active ingredient to the inorganic sludge; In a second step of generating, the inorganic sludge to which the inorganic coagulant is added is dehydrated to generate agglomerated dewatered sludge.

Furthermore, the preparing of the inorganic flocculant may include preparing a first solution by mixing 20 to 50% by weight of hydrochloric acid and 50 to 80% by weight of water based on the total weight of the first solution; Preparing a second solution by mixing 20 to 50% by weight of sodium silicate (Na ₂ SiO ₃ ) with 50 to 80% by weight of water based on the total weight of the second solution; 15 to 40% by weight of the first solution and 60 to 85% by weight of the second solution are mixed with respect to the total weight of the third solution, while the first solution is stirred and the agent is stirred at 40 to 70 ° C. for 100 to 200 minutes. Adding a second solution dropwise to the first solution to prepare a third solution; Preparing a fourth solution by mixing 10 to 30% by weight of the third solution, 1 to 10% by weight of ferric chloride (FeCl ₃ ), and 60 to 85% by weight of water, based on the total weight of the fourth solution; And hydrochloric acid to complete the inorganic flocculant so that the pH of the fourth solution is 1.4 to 1.7.

In addition, between the fourth step of obtaining the secondary supernatant and the fifth step of recovering the ferrous chloride, removing impurities contained in the iron powder; and recovering the ferrous chloride The fifth step is a first auxiliary supernatant produced by reacting for 12 to 30 hours after mixing 50 to 80% by weight of the secondary supernatant with 1 to 10% by weight of the iron powder from which impurities are removed, based on the total weight of the mixture The sixth step of treating the water is characterized in that the wastewater of the organic matter is treated by the Fenton process with the Fenton reagent containing the first auxiliary supernatant.

Recovery and recycling circulation method of iron contained in the Fenton inorganic sludge according to the present invention,

1) The recovery and recycling of ferrous chloride from Fenton inorganic sludge is repeated in the process, which reduces the amount of Fenton reagent chemicals and provides inorganic sludge reduction and treatment effect.

2) By adding a flocculant to the Fenton inorganic sludge, not only can the inorganic sludge be dehydrated easily, but also the dewatered sludge can be easily produced.

3) By removing impurities in the iron powder and producing a refined iron powder, the recovery rate of ferrous chloride is further improved.

1 is a conceptual diagram showing a schematic process of the process of the present invention.
2 is a flow chart showing the overall process of the process of the present invention.
Figure 3 is a flow chart showing the step of producing an inorganic flocculant of the present invention.
Figure 4 is a flow chart showing the step of removing impurities of the iron powder of the present invention.
Figure 5 is a flow chart showing the step of producing a refined iron powder of the present invention.
Figure 6 is a flow chart showing the step of anti-oxidation treatment of the refined iron powder of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The accompanying drawings are not drawn to scale, and like reference numerals in each of the drawings refer to like elements.

1 is a conceptual diagram showing a schematic process of the process of the present invention, Figure 2 is a flow chart showing the overall process of the process of the present invention.

Referring to FIGS. 1 and 2, the iron recovery and recycling circulation method included in the Fenton inorganic sludge of the present invention is obtained from the inorganic sludge generated after water treatment of organic wastewater (eg, dye wastewater) through the Fenton process. The present invention relates to a method for recovering ferrous chloride (FeCl ₂ ), wherein the recovered ferrous chloride is used again as a Fenton reagent in the Fenton process, and ferrous chloride (FeCl ₂ ) is again recovered from the inorganic sludge generated in the Fenton process. It provides a function to reduce the amount of Fenton reagent used in the dye wastewater treatment through an iterative circulation process to recover and recycle to the wastewater treatment process.

In this case, the Fenton process refers to a process of oxidizing organic matter in wastewater through redox reaction by OH radicals generated from hydrogen peroxide (H ₂ O ₂ ) using _divalent iron salt (Fe ²⁺ ) as a catalyst. do. Since the Fenton process is a well known process, a detailed description of the principle and operation will be omitted.

Referring to the basic process of the process of the present invention, the process of the present invention basically obtains the first step (S100) for generating inorganic sludge, the second step (S200) for generating dewatered sludge, and the primary supernatant A third step (S300), a fourth step (S400) of obtaining a secondary supernatant, a fifth step (S500) of recovering ferrous chloride, and a sixth step of treating the wastewater of the organic material through a Fenton process. Step S600 and a seventh step S700 of repeating the first to sixth steps.

First, the first step (S100) of generating inorganic sludge is a process of generating inorganic sludge by treating organic wastewater with Fenton's reagent through the Fenton process, and OH radicals due to the reaction of divalent iron salt of Fenton's reagent with hydrogen peroxide Organic matter is decomposed and inorganic sludge is produced. In this case, the Fenton reagent generally refers to a substance containing a divalent iron salt, but in this step, a substance containing a divalent iron salt and hydrogen peroxide are referred to. Most of the divalent iron salts used as reaction catalysts are inorganic sludge in the form of iron hydroxide. Included in

Thereafter, the second step (S200) of generating dewatered sludge is a process of generating dewatered sludge by concentrating the inorganic sludge in a concentration tank and then dehydrating the sludge, wherein dewatered sludge refers to inorganic sludge from which moisture is removed. In this case, the dewatered sludge may have a water content of 65 to 70%. Such dewatered sludge may be dehydrated by a sludge dehydrator or by dehydrating chemicals into inorganic sludge, and the method is not limited. At this time, in the dewatered sludge, iron used as a catalyst after the Fenton process in an acid state is present in a large amount as iron salt of iron hydroxide (Fe (OH) ₃ ) form through a neutralization reaction.

) 1차 상등액에는 이온화된 염화제2철(

)과 반응하지 않은 염산이 존재하게 된다.(즉, 1차 상등액에는 다량의 3가 철염이 존재하게 된다.)Next, a third step (S300) of obtaining a primary supernatant is a process of obtaining a primary supernatant produced by mixing 20 to 50% by weight of the dehydrated sludge and 50 to 80% by weight of hydrochloric acid based on the total mixture weight. Ferric chloride is produced by mixing hydrochloric acid with dehydrated sludge containing a large amount of iron salt (Fe ³⁺ ) (

) The primary supernatant contains ionized ferric chloride (

Hydrochloric acid, which does not react with (), ie large amounts of trivalent iron salts are present in the primary supernatant.

Here, the mixture means that two or more substances are mixed, and the supernatant means a solution present in the upper layer after the mixture is precipitated in the lower layer of the container, assuming that the mixture is in a separate container.

Thereafter, the fourth step (S400) of obtaining the secondary supernatant is obtained by mixing the unreacted dehydrated sludge and the primary supernatant not participating in the reaction in the third step (S300) of obtaining the primary supernatant to obtain a secondary supernatant. Specifically, a process of obtaining 20% by weight of unreacted dehydrated sludge and 50% by weight to 80% by weight of the primary supernatant to obtain a secondary supernatant.

This is accomplished by mixing a primary supernatant containing trivalent iron salt and hydrochloric acid (ie ferric chloride) with an unreacted inorganic sludge containing iron hydroxide to produce a secondary supernatant by reaction of hydrochloric acid and iron hydroxide. It may be possible to include higher levels of trivalent iron salts than the primary supernatant.

Next, the fifth step (S500) of recovering the ferrous chloride is mixed with 90 to 99% by weight of the secondary supernatant and 1 to 10% by weight of the iron powder relative to the total weight of the mixture and reacted for 12 to 30 hours It is a process of recovering ferrous chloride by obtaining the resulting tertiary supernatant.

) 상기 3차 상등액은 염화제1철을 유효 성분으로 포함한다는 것을 알 수 있다. 즉, 상기 3차 상등액은 2가 철염을 유효 성분으로 포함한다고 할 수 있다. 이때 염화제2철과 철 분말이 충분히 반응할 수 있도록 반응 시간을 조절할 수 있다.At this time, ferrous chloride is produced due to the reaction of ferric chloride and iron powder (Fe) present in the secondary supernatant (

It can be seen that the tertiary supernatant contains ferrous chloride as an active ingredient. That is, the tertiary supernatant may be said to include a divalent iron salt as an active ingredient. At this time, the reaction time can be adjusted so that the ferric chloride and the iron powder can sufficiently react.

Next, a sixth step (S600) of treating the organic wastewater through the Fenton process is a process of treating the wastewater of the organic matter by the Fenton process by using the tertiary supernatant as a catalyst for the Fenton reaction, and recovers the recovered iron. By converting it into iron and recycling it back to the Fenton process, it provides the ability to reprocess the organic wastewater. That is, from the inorganic sludge produced by the water treatment, the divalent iron salt used as the OH radical generating catalyst in the Fenton process is regenerated and recycled to the wastewater treatment.

Finally, the seventh step (S700) of repeating the first to sixth step (S700), as described above, by mixing hydrochloric acid in the inorganic sludge produced through the wastewater treatment to produce ferric chloride and ferric chloride and After ferrous chloride is mixed with iron powder to produce ferrous chloride, the ferric chloride is used again in wastewater treatment to enable the circulation of the divalent iron salt.

At this time, steps not described above among the steps shown in FIG. 2 will be described with reference to FIGS. 3 to 6 to be described later.

Here, the method of the present invention can increase the cohesion of the inorganic sludge by adding a coagulant made of an inorganic material to the inorganic sludge in order to increase the cohesion of the sludge to facilitate the dehydration. A description thereof will be given below with reference to FIG. 3.

Figure 3 is a flow chart showing the step of producing an inorganic flocculant of the present invention.

2 and 3, a step (S110) of adding an inorganic flocculant to the inorganic sludge is further performed between the first step (S100) of generating the inorganic sludge and the second step (S200) of generating the dewatered sludge. Can be.

In this case, the inorganic coagulant refers to a coagulant made of an inorganic substance, and examples thereof include an aluminum salt coagulant and an iron salt coagulant. At this time, the organic flocculant composed of organic materials has a disadvantage in that the selection of the organic flocculant is difficult and the operating conditions of the water treatment process are difficult depending on the components of the wastewater to be treated.

In particular, the aluminum salt flocculant of the inorganic flocculant has the advantage that the flocculation effect is remarkable, there is a disadvantage that it is harmful to the human body, such as neurological diseases when included in drinking water. On the other hand, the iron salt coagulant is good to floc (floc) formation, the sedimentation rate is fast and has little effect on the human body, it is preferable to use the iron salt coagulant as inorganic coagulant.

In this case, in order to simultaneously have the advantages of iron salts having a better flocculation effect than aluminum salt flocculants and less affecting the human body, an inorganic flocculant comprising iron salts and silicates as an active ingredient is prepared. It is possible to produce agglomerated dewatered sludge treated with dehydration.

The preparing of the inorganic flocculant may include preparing a first solution (S111), preparing a second solution (S112), preparing a third solution (S113), and preparing a fourth solution (S114). ), May comprise the step (S115) of completing the inorganic flocculant.

First, preparing a first solution (S111) is a process of preparing a first solution by mixing 20 to 50% by weight of hydrochloric acid and 50 to 80% by weight of water based on the total weight of the first solution. Step S112 is a process of preparing a second solution by mixing 20 to 50% by weight of sodium silicate (Na ₂ SiO ₃ ) with 50 to 80% by weight of water based on the total weight of the second solution.

The first solution is an aqueous hydrochloric acid solution, and serves as a reactant for preparing an inorganic flocculant having an iron salt and a silicate as an active ingredient, which will be described later in the next step. In addition, the second solution is an aqueous sodium silicate solution and is a starting material for preparing an inorganic flocculant. At this time, the silicate is an effective coagulant and the inorganic coagulant having the active ingredient may also have an excellent coagulant function.

Thereafter, in the preparing of the third solution (S113), the first solution is mixed with 15 to 40 wt% and the second solution with 60 to 85 wt% based on the total weight of the third solution. The second solution is added dropwise to the first solution at 100 to 200 minutes at 70 ° C. to prepare a third solution.

This is a process of reacting a first solution of aqueous hydrochloric acid solution and a second solution of sodium silicate solution to produce an acidic polymerization silicic acid solution (H ₂ SiO ₃ ), which is mixed by adding a second solution dropwise to the first solution. Allow the polymerization of hydrochloric acid and sodium silicate to occur slowly.

Next, the step (S114) of preparing a fourth solution includes 10 to 30% by weight of the third solution, 1 to 10% by weight of ferric chloride (FeCl ₃ ), and 60 to 85% by weight of water, based on the total weight of the fourth solution. To prepare a fourth solution by mixing.

This is a process of preparing a fourth solution, which is a flocculant containing silicate and trivalent iron salt as an active ingredient, wherein the aggregation efficiency of the inorganic flocculant is maximized when the weight ratio of the above-mentioned third solution and ferric chloride is maximized. It is preferable to mix 10 to 30 weight% of silver and ferric chloride at 1 to 10 weight%.

Finally, the step (S115) of completing the inorganic coagulant is a process of completing the inorganic coagulant by adding hydrochloric acid such that the pH of the fourth solution is 1.4 to 1.7.

pH is one of the factors influencing water treatment. The inorganic coagulant having silicate and iron salt as the active ingredient has the highest aggregation efficiency under acidic conditions, so the pH of the fourth solution is 1.4 to 1.7, preferably pH 1.5 days. When the flocculation efficiency can be maximum.

The inorganic sludge added with the inorganic flocculant prepared as described above can easily remove moisture from the inorganic sludge with improved cohesion and improved cohesion, thereby enabling efficient dehydration treatment of the inorganic sludge. Accordingly, in the second step, the inorganic sludge to which the inorganic flocculant is added may be dehydrated to generate flocculated dewatered sludge, and the next process step may be performed from the flocculated dewatered sludge.

In the method of the present invention, the fifth step (S500) is a process of recovering ferrous chloride by obtaining a tertiary supernatant by mixing a secondary supernatant containing ferric chloride as an active ingredient and iron powder. In this case, the iron powder as a reactant may include impurities. When impurities are included in the reactants, not only the reactivity may be lowered, but the yield of the product may be reduced. In order to prevent this phenomenon, the iron powder may increase the purity through a separate process of removing impurities, which will be described below with reference to FIG. 4.

Figure 4 is a flow chart showing the step of removing impurities of the iron powder of the present invention.

2 and 4, a step of removing impurities contained in the iron powder between the fourth step S400 of obtaining the secondary supernatant and the fifth step S500 of recovering ferrous chloride (S410). ) May be included.

Since the iron powder from which the impurities are removed is higher in purity than before the impurities are removed, the iron powder may react with the ferric chloride as much as this, and thus, the production of ferrous chloride may be facilitated.

Therefore, in order to increase the purity of the iron powder to increase the reactivity with ferric chloride, the step of removing impurities of the iron powder is to prepare a preparation solution (S411), to obtain a filtrate (S412), and washing After the drying may include a step (S413).

First, the step of preparing the preparation solution (S411) is a separate container of the anaerobic conditions, mixed with 10 to 40% by weight of iron powder and 60 to 90% by weight of water relative to the weight of the total preparation solution to prepare a preparation solution by sealing It's a process.

Since iron is a metal having excellent reducing power, it is preferable to proceed with the above step in a separate container under anaerobic conditions in order to prevent redox from occurring due to a redox reaction due to the mixing of iron and water. At this time, if the water is less than 60% by weight, it cannot be in the form of a solution when it is mixed with the iron powder, and if it exceeds 90% by weight, iron hydroxide is generated by the reaction of iron and water, thereby reducing the number of ferric iron (Fe), so that , 10 to 40% by weight of the iron powder and 60 to 90% by weight of water is preferably prepared to prepare a preparation solution.

Thereafter, the step of obtaining a filtrate (S412) is a process of sonicating the prepared solution for 1 to 5 hours and then filtering to obtain a filtrate.

The preparation solution is prepared by mixing iron powder and water, and may perform a process of sonicating the preparation solution to evenly disperse the iron powder in the preparation solution in water. In this case, not only the iron powder but also the impurities contained in the iron powder may be dispersed together during the sonication process, which may be removed through a filtration process. Here, in order to prevent oxidation of the highly reactive iron powder in the filtration process, it is preferable to filter using a nylon filter, through which impurities can be removed from the iron powder and high purity iron powder can be obtained again. At this time, the iron powder passes through the filter paper and impurities remain in the filter paper to remove impurities of the iron powder, it is preferable that the mesh of the filter paper (or the size of the fine pores) is smaller than the mesh of the iron powder.

In this case, the filtrate means a solution obtained by filtering the preparation solution by a filtration filter, and the filtrate in this step includes iron powder and water from which impurities are removed.

Finally, drying after washing (S413) is a process of washing the filtrate with acetone 1 to 5 times and then drying.

In this case, the filtrate is a mixture of iron powder and water from which impurities are removed, and a part of the iron powder may be oxidized by reacting with moisture in the air by preparing the preparation solution and obtaining the filtrate. In order to remove the oxidized iron, the filtrate is preferably washed 1 to 5 times with acetone. Thus, the filtrate washed with acetone can be obtained by removing the impurities and iron powder by removing water and acetone through a drying process.

That is, the foreign matter is removed from the existing iron powder through the above-described steps to obtain a high-purity iron powder, the ferrous chloride increases the yield of ferrous chloride due to increased reactivity with ferric chloride and waste water of organic matter Recyclability of the Fenton's reagent used to process the catalyst may be increased. Accordingly, in the fifth step S500, 90 to 99% by weight of the secondary supernatant and 1 to 10% by weight of the iron powder from which the impurities are removed are mixed and reacted for 12 to 30 hours, based on the total weight of the mixture. The first supernatant, which is the prepared supernatant, is obtained, and the sixth step is to treat the wastewater of organic matter with the Fenton reagent including the first auxiliary supernatant through the Fenton process.

In this case, the impurities contained in the iron powder may be removed to increase the reactivity with ferric chloride (ie, the tertiary supernatant), but when the iron powder is pulverized to a smaller size than the existing particle size, The increase in specific surface area may increase the reactivity with ferric chloride. A description thereof will be given with reference to FIG. 5.

Figure 5 is a flow chart showing the step of producing a refined iron powder of the present invention.

2 and 5, the smaller the particle size of the iron powder used in the fifth step (S500) of recovering the ferrous chloride, the larger the surface area becomes, and thus, the second step in the fourth step (S400). The reactivity with the secondary supernatant is improved. For this purpose, a step (S420) of preparing the refined iron powder may be additionally performed between the fourth step (S400) and the fifth step (S500).

In this case, a step (S420) of preparing the refined iron powder may be included between the third step (S300) of obtaining the primary supernatant and the fifth step (S500) of recovering ferrous chloride. Since the iron salt concentration of the secondary supernatant in the fourth step (S400) to be obtained is higher, reacting with the micronized iron powder and the secondary supernatant having a high iron salt concentration can efficiently obtain ferrous chloride. It is more preferable to include the step (S420) of producing the micronized iron powder between (S400) and the fifth step (S500).

Here, the refined iron powder refers to an iron powder having a smaller particle size than commercial iron powder, and may be an iron powder having a particle size of nano units.

The step (S420) of manufacturing the micronized iron powder includes the steps of preparing the iron oxide powder (S421), preparing the iron oxide solution (S422), preparing the first powder (S423), and manufacturing the second powder. Step S424 may include a step (S425) of completing the refined iron powder.

First, the step of preparing the iron oxide powder (S421) is a process of manufacturing the iron oxide powder by grinding the iron oxide (Fe ₂ O ₃ ).

Iron oxide is a starting material for producing the refined iron powder, and the grinding process may use a variety of grinders depending on the material to be crushed, in the step of grinding the iron oxide by a ball milling method of the iron oxide that can occur in the grinding process Contamination can be prevented. In particular, the ball is made of steel (steel) material can minimize the contamination of iron oxide during the grinding process. At this time, the iron oxide may be pulverized so that the particle size of the iron oxide powder is evenly formed by setting the mixing ratio (weight basis) of the ball and the iron oxide to 50: 1.

Next, the step of preparing the iron oxide solution (S422) is a process for preparing the iron oxide solution by mixing 10 to 50% by weight of the iron oxide powder and 50 to 90% by weight of methanol relative to the total weight of the iron oxide solution, wherein methanol is in the iron oxide solution As a solvent, it provides a function of preventing particle entanglement of iron oxide powder.

Thereafter, the step of preparing the first powder (S423) is a process of preparing the first powder by drying and grinding the iron oxide solution at 50 to 65 ° C. for 20 to 30 hours.

At this time, since the boiling point of methanol used as the solvent of the iron oxide solution is 64.7 ° C., the drying temperature of the iron oxide solution is preferably set in a range not to exceed the boiling point of methanol (preferably 50 to 60 ° C.).

In addition, the particle size of the pulverized iron oxide powder may be a micron size, but may have a high specific surface area and may be crushed to a nano size in order to have a high reactivity in the steps described later. It may be said that it is preferable to prepare a first powder by grinding.)

Here, the grinding process may use a ball milling method, because the milling target is the iron oxide solution

Next, the step (S424) of preparing the second powder is injected into the reactor and the hydrogen gas at a rate of 4 to 5L / min and then heated to 450 ℃ for 10 to 40 minutes and 30 to 60 minutes During the process of preparing the second powder.

This is a step of reducing the first powder containing iron oxide as an active ingredient with hydrogen, and thus it is possible to generate ductile iron (Fe) by a redox reaction between iron oxide and hot hydrogen gas. That is, the said 2nd powder can use a ductile iron as an active ingredient.

Finally, the step (S425) of completing the refined iron powder is a process of completing the refined iron powder by cooling the second powder to room temperature at a cooling rate of 20 ° C./min under an argon atmosphere.

Since argon is an inert gas, it is possible to create an environment in which the second powder containing iron as an active ingredient does not react, and the cooling rate is 20 ° C./min to prevent an increase in particle size that may occur during cooling. have. As such, the second powder may be cooled to complete the refined iron powder.

The micronized iron powder prepared through this step may recover the ferrous chloride by obtaining a second auxiliary supernatant produced by mixing with the secondary supernatant in the fifth step (S500) of recovering the ferrous chloride. 90 wt% to 99 wt% of the secondary supernatant and 1 wt% to 10 wt% of the finely divided iron powder were mixed with each other for 12 to 30 hours to obtain a second auxiliary supernatant to recover ferrous chloride. can do. Thereafter, in the sixth step S600, the wastewater of the organic material may be treated with the Fenton reagent including the second auxiliary supernatant through the Fenton process.

In addition, the micronized iron powder may be oxidized again due to the reaction with moisture in the air, so to further prevent the micronized iron powder, an additional process for preventing oxidation may be further performed. Referring to Figure 6 as follows.

Figure 6 is a flow chart showing the step of anti-oxidation treatment to the refined iron powder of the present invention.

Referring to FIG. 6, in order to prevent the micronized iron powder from being oxidized again, after the step of completing the micronized iron powder (S425), an anti-oxidation process (S430) may be additionally performed.

In particular, the micronized iron powder has a large specific surface area and can easily be oxidized by reacting with moisture in the air. In order to prevent such a phenomenon, a mixture of vegetable fats as an active ingredient (a detailed description thereof will be described later) is described above. It can be mixed with the refined iron powder to prevent oxidation again.

In other words, by mixing a blending agent containing an unsaturated fatty acid vegetable fat as an active ingredient and the finely powdered iron powder, a mixed agent is present on the surface of the refined iron powder, thereby preventing the contact between the refined iron powder and moisture in the air The oxidation of the iron powder can be prevented.

The anti-oxidation step (S430) specifically includes preparing a mixed solution (S431), preparing a premix (S432), preparing a mixed agent (S433), and drying the mixed agent (S434). It may include.

First, the step of preparing a mixed solution (S431) is the total mixed solution weight. 0.1 to 10% by weight of vegetable fat and 90 to 99.9% by weight of ethanol are mixed to prepare a mixed solution.

At this time, ethanol is to play a role as a solvent in the mixed solution, by heating the ethanol at 65 to 75 ℃ can be easily mixed with the vegetable fat in the liquid. Here, the heating temperature of ethanol is preferably set to a temperature range (preferably 65 to 75 ° C) lower than 78.37 ° C, which is the boiling point of ethanol.

In addition, the vegetable fat is an unsaturated fatty acid, and has a liquid phase, thereby providing a function of forming a film on the surface of the micronized iron powder during oxidation treatment of the micronized iron powder through the steps described below. In this case, the vegetable fat may be oleic acid, linoleic acid, etc., and the melting point is low and exists in a liquid state at room temperature. These vegetable fats play a role in inhibiting the oxidation of the refined iron powder.

Here, the micronized iron powder which has been subjected to the oxidation treatment through the steps to be described later may wash out the mixture present on the surface through the fourth step (S400) to the sixth step (S600) to participate in the redox reaction. (The vegetable fat is liquid, so it is possible to wash it out through the fourth to sixth steps.)

Next, the step (S432) of preparing the premixing agent is a process of preparing a mixed powder by mixing 30 to 50% by weight of the micronized iron powder and 50 to 70% by weight of the mixed solution, relative to the total premixer weight, and finely ironed It can be said that it forms a film by the mixed solution which uses vegetable fat as an active ingredient on the surface of powder.

Thereafter, the step of preparing a mixture (S433) is a process of preparing a mixture by mixing 90 to 99% by weight of the premixing agent with 1 to 10% by weight of normal octanol, based on the total weight of the mixture, wherein the normal octanol is It serves to prevent the iron powder from agglomerating.

Finally, the step of drying the mixture (S434) is a process of drying the mixture at 40 to 70 ℃ after stirring the mixture for 5 to 10 hours, it can be completed through the anti-oxidized finely divided iron powder.

Such a mixture is a result of preventing oxidation of the micronized iron powder by forming a film with vegetable fat on the surface of the micronized iron powder, thereby recovering the ferrous chloride through the additional supernatant in the fifth step (S500). The reaction can recover ferrous chloride.

That is, in the fifth step (S500) of recovering the ferrous chloride, after mixing 90 to 99% by weight of the secondary supernatant with 1 to 10% by weight of the micronized iron powder, which is subjected to oxidation, based on the total mixture weight The reaction can be carried out for 12 to 30 hours to obtain a third auxiliary supernatant to recover ferrous chloride, from which iron salt can be recycled to treat the organic wastewater. Accordingly, the sixth step S600 is to treat the wastewater of the organic matter with the Fenton reagent including the third auxiliary supernatant through the Fenton process.

As described so far, the configuration and operation of the recovery and recycling circulation method of iron contained in the Fenton inorganic sludge according to the present invention has been expressed in the above description and drawings, but this is merely an example and the idea of the present invention is described above. And not limited to the drawings, various changes and modifications are possible within the scope not departing from the technical idea of the present invention.

S100: first step of generating inorganic sludge
S110: adding an inorganic flocculant
S111: preparing a first solution
S112: preparing a second solution
S113: preparing a third solution
S114: preparing a fourth solution
S115: step of completing the inorganic flocculant
S200: second step of generating dewatered sludge
S300: third step of obtaining the primary supernatant
S400: fourth step to obtain a secondary supernatant
S410: removing impurities in the iron powder
S411: preparing a preparation solution
S412: obtaining a filtrate
S413: step of washing and drying
S420: step of preparing the refined iron powder
S421: step of producing iron oxide powder
S422: preparing an iron oxide solution
S423: preparing a first powder
S424: preparing a second powder
S425: step of completing the refined iron powder
S430: Antioxidation Step
S431: step of preparing a mixed solution
S432: preparing a premix
S433: preparing a mixture
S434: drying step
S500: fifth step to recover ferrous chloride
S600: 6th step of water treatment through Fenton process
S700: Seventh step of repeating the first to sixth steps

Claims (9)

The recovery and recycling cycle of iron contained in Fenton inorganic sludge,
A first step of treating the wastewater of organic matter with a Fenton reagent through a Fenton process to generate inorganic sludge;
A second step of concentrating the inorganic sludge in a concentration tank and then dehydrating to produce dewatered sludge;
A third step of obtaining a primary supernatant produced by mixing 20 to 50 wt% of the dehydrated sludge and 50 to 80 wt% of hydrochloric acid based on the total weight of the mixture;
A fourth step of obtaining a secondary supernatant obtained by mixing 20 to 50 wt% of unreacted dehydrated sludge with 50 to 80 wt% of the primary supernatant, based on the total weight of the mixture;
A fifth to recover ferrous chloride by mixing 90 to 99% by weight of the secondary supernatant with 1 to 10% by weight of iron powder, and then reacting for 12 to 30 hours to obtain the resulting tertiary supernatant relative to the total weight of the mixture. step;
A sixth step of treating the wastewater of the organic material with the Fenton reagent including the tertiary supernatant through a Fenton process;
And a seventh step of repeating the first to sixth steps; recovering and recycling iron contained in the Fenton inorganic sludge. The method of claim 1,
Between the first step of generating the inorganic sludge and the second step of generating the dewatered sludge,
And adding an inorganic flocculant having an iron salt and a silicate as active ingredients to the inorganic sludge.
The second step of generating the dewatered sludge,
Recovering and recycling the iron contained in the Fenton inorganic sludge by dewatering the inorganic sludge to which the inorganic coagulant is added to produce agglomerated dewatered sludge. The method of claim 2,
Preparing the inorganic flocculant,
Preparing a first solution by mixing 20 to 50 wt% hydrochloric acid and 50 to 80 wt% water based on the total weight of the first solution;
Preparing a second solution by mixing 20 to 50% by weight of sodium silicate (Na ₂ SiO ₃ ) with 50 to 80% by weight of water based on the total weight of the second solution;
15 to 40% by weight of the first solution and 60 to 85% by weight of the second solution are mixed with respect to the total weight of the third solution, while the first solution is stirred and the agent is stirred at 40 to 70 ° C. for 100 to 200 minutes. Adding a second solution dropwise to the first solution to prepare a third solution;
Preparing a fourth solution by mixing 10 to 30% by weight of the third solution, 1 to 10% by weight of ferric chloride (FeCl ₃ ), and 60 to 85% by weight of water, based on the total weight of the fourth solution;
Comprising: adding hydrochloric acid so that the pH of the fourth solution is 1.4 to 1.7 to complete the inorganic flocculant; recovery, recycling cycle method of iron contained in the Fenton inorganic sludge. The method of claim 1,
Between the fourth step of obtaining the secondary supernatant and the fifth step of recovering the ferrous chloride,
Removing impurities contained in the iron powder; and
The fifth step of recovering the ferrous chloride,
50 to 80% by weight of the secondary supernatant and 1 to 10% by weight of the iron powder from which the impurities are removed are mixed with respect to the total weight of the mixture, followed by reaction for 12 to 30 hours to obtain a first auxiliary supernatant.
The sixth step of treating the water,
The wastewater of organic matter is treated with the Fenton reagent containing the first auxiliary supernatant through the Fenton process, recovery and recycling circulation method of iron contained in the Fenton inorganic sludge. The method of claim 4, wherein
Removing the impurities,
Preparing a preparation solution by mixing 10 to 40% by weight of the iron powder with 60 to 90% by weight of water in a separate container in anaerobic condition and then sealing the mixture;
Sonicating the preparation solution for 1 to 5 hours and then filtering to obtain a filtrate;
Washing the filtrate with acetone 1 to 5 times and drying the method; recovery, recycling cycle method of iron contained in the Fenton inorganic sludge. The method of claim 1,
Between the fourth step of obtaining the secondary supernatant and the fifth step of recovering the ferrous chloride,
Preparing an iron powder refined to have particles of a smaller size than the iron powder;
The fifth step of recovering the ferrous chloride,
90 to 99% by weight of the secondary supernatant and 1 to 10% by weight of the refined iron powder were mixed with respect to the total weight of the mixture, followed by reaction for 12 to 30 hours to obtain a second auxiliary supernatant to recover ferrous chloride. ,
The sixth step of treating the water,
The Feton reagent containing the second auxiliary supernatant, characterized in that the waste water of the organic material is treated by the Fenton process, recovery and recycling circulation method of iron contained in the Fenton inorganic sludge. The method of claim 6,
Preparing the micronized iron powder,
Milling iron oxide (Fe ₂ O ₃ ) to produce iron oxide powder;
Preparing an iron oxide solution by mixing 10 to 50 wt% of the iron oxide powder with 50 to 90 wt% of methanol, based on the total weight of the iron oxide solution;
Preparing a first powder by drying the iron oxide solution at 50 to 65 ° C. for 20 to 30 hours and then pulverizing;
Preparing a second powder by introducing the first powder into a reactor and then injecting hydrogen gas at a rate of 4 to 5 L / min, then raising the temperature to 450 ° C. for 10 to 40 minutes and maintaining for 30 to 60 minutes;
Cooling the second powder to room temperature under an argon atmosphere at a cooling rate of 20 ° C./min to complete a finely divided iron powder; and recovering and recycling the iron contained in the Fenton inorganic sludge. . The method of claim 7, wherein
After the step of completing the refined iron powder,
And an anti-oxidation treatment of the micronized iron powder with a mixture containing the micronized iron powder and vegetable fat as an active ingredient.
The fifth step of recovering the ferrous chloride,
90 to 99% by weight of the secondary supernatant and 1 to 10% by weight of the antioxidized micronized iron powder were mixed with respect to the total weight of the mixture, followed by reaction for 12 to 30 hours to obtain a third auxiliary supernatant. Recovers iron,
The sixth step of treating the water,
The Feton reagent containing the third auxiliary supernatant, characterized in that the waste water of the organic material is treated by the Fenton process, recovery and recycling circulation method of iron contained in the Fenton inorganic sludge. The method of claim 8,
The antioxidant treatment step,
By weight of total mixed solution. Preparing a mixed solution by mixing 0.1 to 10% by weight of vegetable fat and 90 to 99.9% by weight of ethanol;
Preparing a premixing agent by mixing 30 to 50 wt% of the micronized iron powder and 50 to 70 wt% of the mixed solution, based on the total weight of the premixing agent;
Preparing a mixture by mixing 90 to 99% by weight of the pre-mixer with 1 to 10% by weight of normal octanol, based on the total weight of the mixture;
After stirring the mixture for 5 to 10 hours and drying at 40 to 70 ℃; recovery, recycling cycle method of iron contained in the Fenton inorganic sludge.

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