KR100672089B1 - Method for manufacturing iron-nickel alloy mass using feni containing sludge - Google Patents

Abstract

A method for manufacturing a Fe-Ni alloy mass with excellent strength and high purity more economically by pelletizing FeNi powder in the middle of reduction heat treatment, thereby utilizing FeNi-containing sludge is provided. A method for manufacturing Fe-Ni alloy mass using FeNi-containing sludge comprises the steps of: neutralizing FeNi-containing sludge with a neutralizer to remove chlorine from the FeNi-containing sludge, and drying the chlorine removed FeNi-containing sludge to a moisture content of 5% or less; deagglomerating the dried sludge into powder with an average particle size of 30 to 700 mum; molding the deagglomerated powder into an molded body with a molding density range of 1.7 to 4.7 g/cc; increasing temperature of the molded body at a temperature increasing rate of 100 deg.C/min or less to sinter the molded body at 500 to 950 deg.C; performing heat treatment of the sintered material by primarily reducing the sintered material in a temperature range of 500 to 750 deg.C under a reductive gas atmosphere for 15 to 60 minutes, and secondly reducing the primarily reduced sintered material in a temperature range of 750 to 1000 deg.C for 15 to 60 minutes such that sintering reaction is occurred during the reduction; and cooling and extracting the reduced and sintered alloy mass.

Description

Method for Manufacturing Iron-Nickel Alloy Mass Using FeNi Containing Sludge}

The present invention relates to a method for recycling Ni-containing wastes, and more particularly, to a method for producing FeNi alloy ingots used for raw materials of stainless steel using FeNi-containing sludge.

FeNi-containing sludge is generated in the etching process of the shadow mask manufacturing process.

The shadow mask is manufactured through a process of localizing a Ni-containing Fe alloy, that is, an Invar alloy, with a FeCl ₃ etching solution.

In the continuous etching process, the Inba alloy base material is dissolved and FeCl ₂ and NiCl ₂ are generated in the solution by the following reaction.

2FeCl ₃ + Ni = 2FeCl ₂ + NiCl ₂

2FeCl ₃ + Fe = 3FeCl ₂

Therefore, when the work is progressed to some extent and the content of FeCl ₂ and NiCl ₂ increases, the etching ability decreases. This phenomenon is said to increase the fatigue of the solution.

Therefore, if the FeCl ₂ and NiCl ₂ incorporation increases above a certain concentration for fatigue control, the solution is discarded and a new FeCl ₃ solution should be used.

The etching waste solution thus produced is mainly subjected to Fe powder treatment by replacing Ni with Fe powder to remove the chlorine oxide and recycling the solution into FeCl ₃ (Japanese Patent Laid-Open No. 1995-87474).

FeCl ₃ The recycling method relates to a method of electrochemically replacing and depositing Ni ions produced by the reaction scheme (1), the reaction scheme of which is represented by the following reaction formula (3).

NiCl ₂ + 2Fe = FeNi + FeCl ₂

As a method for recycling the FeNi sludge produced by the reaction scheme (3), a method of separating and recovering FeOOH and NiO has been proposed. (Korean Patent Application No. 1998-56697, Patent Registration No. 0406367)

The above described FeNi sludge recycling method is as follows.

That is, FeNi-containing sludge is dissolved in hydrochloric acid so as to have a pH of 3 to 4 to prepare an iron chloride and nickel chloride-containing aqueous solution, and the air is oxidized by blowing air into the chloride-containing aqueous solution to oxidize FeCl ₂ to FeCl ₃ .

Next, FeCl ₃ produced as described above was reacted with water at pH ₃ to 5 to form an orange iron hydroxide (FeOOH) nucleus, and at a maximum molar number of moles of Fe in the solution under an oxidizing atmosphere, and at pH 3 The temperature is adjusted to 40-70 ° C. while the alkali is added so as to remain at -5 to form iron hydroxide sludge.

Next, the iron hydroxide sludge formed as above is filtered to separate the iron hydroxide sludge and the nickel chloride-containing filtrate, and the iron hydroxide sludge is washed with water to obtain iron hydroxide.

An alkali is added to the filtrate separated during filtration to have a pH of 10 or more to form a precipitate of nickel hydroxide, which is filtered and washed with water to obtain nickel hydroxide.

However, the FeNi sludge recycling method has a problem such as a complicated process and limit the utilization of FeOOH recovered.

Therefore. The inventors have filed a patent application using a FeNi sludge to develop a technology for recovering the metal powder containing Fe and Ni. (Korean Patent Application No. 2004-0107059)

In the case of using the metal powder containing Fe and Ni recovered by the above technique as raw materials for stainless steel, the alloy powder is manufactured by agglomerating the powder since problems such as lowering of the real rate are caused by scattering in the dust state when the converter is introduced. The process to do is necessary.

The alloy ingot is required to have a strength of 100 kg / cm ² or more, preferably 150 kg / cm ² or more in order to prevent powdering due to impact when charged in addition to the purity.

Therefore, in order to prepare the powder obtained by the above method into an alloy ingot which satisfies the required strength of the stainless steel alloy ingot by the general solidification method, a caking additive, such as quicklime and PVA (polyvinyl alcohol), is added. It must be mixed molded.

However, the caking additive added to agglomerate the powder has a problem such as lowering the purity of the raw material and has to be wet-mixed during the agglomeration process, so there is a problem that the drying process must be doubled.

An object of the present invention is to provide a method for more economically manufacturing FeNi alloy ingots having excellent strength and high purity by utilizing FeNi-containing sludge by agglomerating FeNi powder during reduction heat treatment.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The present invention comprises the steps of neutralizing the FeNi-containing sludge with a neutralizer to remove chlorine, and then drying the sludge to 5% or less moisture content;

Pulverizing the dried sludge to have a particle size of 30-700 μm (micrometer);

Molding the pulverized powder as described above to have a molding density in the range of 1.7-4.7 g / cc;

Heating the molded article molded as described above in a temperature range of 500-950 ° C. at a temperature rising rate of 100 ° C./min or less;

The calcined product as described above is heated up in a reducing gas atmosphere to reduce the primary by 15-60 minutes in the range of 500-750 ° C, and the secondary reduction heat treatment for 15-60 minutes in the range of 750-1000 ° C during reduction. Heat-treating the sintering reaction to occur;

It relates to a method for producing an iron nickel alloy ingot using iron nickel (FeNi) containing sludge comprising the step of cooling and taking out the reduced sintered alloy ingot.

In addition, the present invention is to remove the chlorine and water by firing FeNi-containing sludge at a heat treatment temperature of 600-900 ℃;

Pulverizing the calcined sludge to have a particle size of 30-700 μm;

Molding the pulverized powder as described above to have a molding density in the range of 1.7-4.7 g / cc;

The molded body is first reduced for 15-60 minutes in a range of 500-750 ° C. under a reducing gas atmosphere, and heat-reduced to undergo a sintering reaction during reduction by secondary reduction heat treatment for 15-60 minutes in a range of 750-1000 ° C. step; And

It relates to a method of manufacturing iron nickel alloy ingot using iron nickel (FeNi) containing sludge, characterized in that it comprises the step of cooling the reduced sintered alloy ingot.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention is applied to a method for producing FeNi alloy ingots used in raw materials for stainless steel production using FeNi sludge.

FeNi-containing sludge that can be utilized by the present invention is not particularly limited.

FeNi-containing sludge that can be preferably used in the present invention includes FeNi-containing sludge which is a secondary waste generated in the process of recycling the etching waste liquid generated in the shadow mask manufacturing process of the electronics company.

In order to manufacture the FeNi alloy mass according to the present invention, it is necessary to first remove Cl contained in the FeNi-containing sludge. As a representative method, a method of removing Cl by neutralizing the FeNi-containing sludge with a neutralizer and removing Fe and the FeNi-containing And a method of removing Cl by heat treating the sludge at 600-900 ° C.

First, a method of neutralizing water washing with FeNi-containing sludge with a neutralizing agent to remove Cl will be described.

FeCl ₂ is contained in the sludge because the FeNi sludge formation reaction, that is, the reaction formula (3) occurs in the aqueous solution.

In addition, since a considerable amount of Fe and Ni hydroxides exist in the reaction according to the passivation of Fe and Ni during the reaction of the reaction formula (3), the hydroxide may be reduced-heat treatment to obtain FeNi metal.

In the above reduction heat treatment, FeCl ₂ contained in the FeNi sludge and Cl in the passivated sludge may cause corrosion of the equipment during the heat treatment and release a large amount of toxic gas and dust. shall.

That is, when a neutralizing agent such as NaOH or the like is added to the Cl-containing sludge to increase the pH to 9-12, FeNi of the metal component does not react, but the Cl-containing component causes reactions such as the following reaction formulas (4) and (5).

FeCl ₂ + ₂ NaOH / Ca (OH) ₂ = Fe (OH) ₂ + NaCl / CaCl ₂

2 (Fe, Ni) (OH) Cl + 2NaOH / Ca (OH) ₂ = 2 (Fe, Ni) (OH) ₂ + 2NaCl / CaCl ₂

In other words, neutralization of FeCl ₂ as well as Cl in the passivated sludge neutralizes NaCl, and NaCl is a soluble salt, so it is possible to remove 2 (Fe, Ni) (OH) _2, etc. It is possible to remove Cl without losing Fe and Ni.

As the neutralizing agent of the present invention, any kind of neutralizing agent having solubility with Cl can be used.

Neutralizing agents that can be preferably applied to the present invention include NaOH, Ca (OH) ₂ , Na ₂ CO ₃ and the like.

Meanwhile, in the present invention, Cl may be removed by heat-treating FeNi-containing sludge, which will be described in detail below.

To remove Cl by heat-treating FeNi-containing sludge, Cl ₂ Volatiles in the form of gas or HCl must be heat treated in a corrosion protection system.

De-Cl by heat treatment is preferentially volatilized when NiCl ₂ is more than 900 ° C. in the iron chloride (Fe, Ni) Cl ₂ , so that Ni decreases.

If the heat treatment temperature is less than 600 ℃ de-Cl does not occur sufficiently, if it exceeds 900 ℃ Ni chloride in the sludge is volatilized, so the de-Cl heat treatment in the 600-900 ℃ range only occurs volatilization by Cl ₂ gas, HCl do.

As described above, the dechlorinated powder does not need a calcining process to remove the water of the hydroxide during the manufacturing process because water is removed when Cl is removed.

Hereinafter, the block formation method of this invention is demonstrated.

As described above, the FeNi sludge from which chlorine is removed should be dried to 5% or less of water content.

The reason for maintaining the water content of the sludge is 5% or less is to facilitate the molding in the subsequent press molding process.

In other words, if the moisture content is high, the molding density decreases and residues remain in the molding machine, which makes it difficult to release the mold (a step in which the molded body falls from the molding machine).

Next, the sludge dried as described above should be pulverized using a ball mill, a vibration mill, or the like, and the sludge dried using a crusher should have a particle size of 30 to 700 µm.

In general, the average particle size of the powder produced in the FeNi sludge is about 100 μm, so if excessive grinding is performed so that the average particle size is less than 30 μm, Fe and Ni contacted by the reaction formula (3) are separated from each other, and alloying is not easy. It is not preferable because the moldability (lower mold density) becomes poor during subsequent press molding.

Therefore, the average particle size of the dried sludge powder is 30 µm or more, more preferably 70 µm or more.

When the particle size of the dried sludge powder exceeds 700 占 퐉, the molding density does not increase, rather the molding density does not increase, but the shape of the molding becomes poor.

Therefore, the particle size of the dried sludge powder should be 30-700㎛.

Next, the powder prepared as described above is molded to prepare a molded body.

Although the molding method that can be used in the present invention is not particularly limited, preferred molding methods include a press molding method and a spherical block forming method.

In the present invention, an appropriate amount of a moldability improving agent may be added to the powder to improve moldability before molding.

As the formability improving agent, one or two or more organic carbon compounds decomposed during heat treatment, for example, molasses, stearic acid, and fatty acids may be added.

When too much of the formability improving agent is added, residual carbon is generated, so the amount of addition is preferably limited to less than 10% of the sludge.

When the molded product is manufactured by the press molding method, the molding pressure should be controlled to have a density of 1.7-4.7 g / cc, and more preferably 2-3.5 g / cc for strength and reduction rate. Do.

When the compact density is less than 1.7 g / cc, breakage occurs during subsequent heat treatment, and / or the compact density after reduction sintering is reduced, and a target compressive strength of 100 Kg / cm ² or more, preferably 150 Kg / cm ² or more, is secured. It becomes difficult to do it.

In addition, when the density of the compact before reduction exceeds 4.7 g / cc, it is difficult to penetrate the reducing gas, so that the reduction, that is, the metallization rate (metallization rate = Fe + Ni content of the reduced sample, the ratio of Fe: Ni in the sample is averaged). 2: 1).

For optimum quality, that is, to achieve high reduction and high strength simultaneously, the optimum compact density is 2-3.5 g / cc.

On the other hand, in this invention, a molded object can also be manufactured by spherical massing.

Even when using the spherical agglomeration method, the compact density should be 1.7-4.7 g / cc, and the reason for this limitation is the same as that of the pressure molding method.

In the case of using the nodular bulking method as described above, when the powder is put into the nodular bulking rotary fan, 5-30% of water is added to the powder, or 5% or less of binder is added with 5-30% of water. can do.

As described above, when the spheroidal block is formed, a drying process is required after the block (moulding) to dry and remove moisture, thereby solidifying.

The drying temperature is preferably at least 100 ℃.

Examples of the binder include polyvinyl alcohol (PVA), starch and the like.

As described above, the compression molded FeNi molded body is preferably subjected to calcination heat treatment before reduction.

Of course, you may calcinate after shaping | molding, and also after calcining the crushed sludge powder, you may shape | mold.

That is, the molding step and the calcining step may be reversed.

Here, calcination heat treatment refers to a heat treatment for removing water from the hydroxide produced by the reaction formulas (4) and (5).

Although the calcination heat treatment process may not be performed, it is preferable to undergo a calcination heat treatment, that is, a dehydration step, since a reduction in reduction rate occurs when the calcination heat treatment process is omitted.

When hydroxide is included in the powder by using NaOH and Ca (OH) ₂ as the neutralizing agent, the calcination heat treatment is preferably performed at 500 ° C or higher.

However, when calcining at a temperature of 950 ℃ or more, the sintering of the molded body proceeds, so that it is difficult to penetrate the reducing gas in the subsequent reduction process, the firing temperature is preferably limited to 500-950 ℃.

On the other hand, calcination heat treatment in the case of using Na ₂ CO ₃ or the like as the neutralizing agent is preferably performed at 900-950 ° C.

In obtaining the Fe-Ni alloy mass according to the present invention, it is preferable that the temperature increase rate in the section where the dehydration reaction takes place be 100 ° C / min or less.

If the temperature increase rate (or the charge rate of the sample into the holding furnace) exceeds 100 ° C / min, a sudden dehydration reaction generates a lot of water vapor in the molded body in a short time, the molded body collapses and it is difficult to maintain the target density or strength .

After reducing and sintering the molded body and the fired body prepared as described above in a reducing gas atmosphere, the sintered alloy ingot is cooled to prepare a final alloy ingot.

As the reducing gas, hydrogen, carbon monoxide, ammonia, and the like can all be used. However, it is preferable to use hydrogen gas that is easy in exhaust gas treatment (combustion) generated after an atmospheric treatment and has excellent reducing power.

The reducing gases may be used alone or in combination, and it is preferable to use a hydrogen-containing gas as the mixed gas.

When the reduction temperature is less than 500 ° C, since the reduction rate is very low, it is difficult to manufacture high purity FeNi alloy ingots, and the reduction temperature should be 500 ° C or higher.

However, when the reduction temperature exceeds 1000 ℃, the rapid inter-particle sintering increases during the reduction, as the sintering reaction is rapidly progressed, it is difficult to penetrate the reducing gas into the molded body, the reduction rate rather decreases.

In the present invention, it is preferable that the primary reduction is performed at 500-750 ° C. for 15-60 minutes, and the secondary reduction is performed at 750-1000 ° C. for 15-60 minutes higher than the primary reduction temperature.

The reason for selecting the primary and secondary reduction temperatures as described above is to allow the high temperature sintering to be performed at the reduction end point by subsequent heating by allowing the reduction to occur sufficiently at a low temperature to prevent initial reduction sintering.

The reduction temperature condition may be treated by dividing the reduction into two stages in a batch type reduction furnace, and may be achieved by controlling the temperature gradient of the reduction furnace in the continuous type.

As described above, by setting the reducing conditions, it is possible to produce FeNi alloy ingots having a high reduction rate and excellent strength.

According to the present invention, FeNi alloy ingots having a purity of at least 85%, preferably at least 95%, and a compressive strength of at least 100 Kg / cm ² , preferably at least 150 Kg / cm ² can be produced.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example 1)

After dissolving the FeNi-containing sludge generated in the FeCl ₃ etching solution recycling process in water, adding sodium hydroxide (NaOH) to the solution containing the sludge, neutralizing it at pH = 10.5, and then filtering the sludge in a solution using a solid-liquid separator. Further water was added to wash the sludge to remove NaCl, an aqueous neutralizing salt.

The de-Cl treated FeNi sludge obtained through the above process was dried under various drying conditions to adjust the water content to 1-8%.

Sludges with various water contents were crushed with a ball mill and classified through a classifier to prepare various dried sludge powders having a particle size of 35-800 μm.

Fe-Ni-containing powders having different water contents and particle sizes were molded to have a rectangular parallelepiped shape (20 mm * 30 mm * 30 mm) in a hydraulic molding machine.

As the molding is shown in Table 1 below, by applying a molding force to the press forming machine to 1 to 5 tons differently to prepare a molded body having a different molding density of the molded body.

After measuring the density of the molded article molded as described above with a density meter, the results are shown in Table 1 below.

The molded article molded as described above was heated up at a temperature increase rate of 20 ° C./min or less and fired at 600 ° C. for 1 hour.

The small body fired as above is placed in a two zone reduction furnace having two temperature sections, heat treated in a primary reduction section for 30 minutes, and then moved to a sample in a secondary reduction (reduction and sintering) section. Heat treatment was performed for a minute.

Reduction conditions are shown in Table 1 below.

After cooling, the heap was prepared by cooling, and the change of shape during the heat treatment of the alloy was observed first, and the breaking strength was investigated by increasing the strength when measuring the compressive strength. Indicated.

After wet analysis of the alloy ingot to determine the Fe and Ni content, the sum is shown in Table 1 as metallization rate.

In Table 1 below, "fail" indicates that the sample broke at a compressive strength within 150 Kg / mm ² during the compressive strength test, and "pass" indicates that the sample did not break at 150 Kg / mm ² or more. It shows that the compressive strength is 100-150Kg / mm ² .

 Sample No. Molding conditions Reduction temperature (℃) Molded body shape Fe + Ni concentration (% by weight) Compressive strength test Water content (%) / particle size (㎛) / molding force (ton) Density (g / cc) 1st reduction Secondary Reduction (Reduction Sintering) Comparative material 1 8/220/1 1.6 600 820 Breaking 97.2 Fail Invention 1 3/220/3 2.7 600 820 Good 99.1 Pass Invention Material 2 2/180/3 2.5 600 820 Good 97.8 Pass Invention 3 2/120/3 2.3 600 820 Good 97.8 Pass Invention 4 3/35/3 2.0 600 820 Good 98.2 conditional pass Invention 5 3/290/3 2.6 600 820 Good 99.0 Pass Invention Material 6 2/350/3 2.8 600 820 Good 99.4 Pass Invention Material 7 3/510/3 3.4 600 820 Good 99.1 Pass Comparative material 2 4/1000/6 4.8 600 820 Good 83.8 Fail Invention Material 8 3/510/5 3.9 600 820 Good 87.4 Pass Invention Material 9 2/220/4 2.8 600 820 Good 96.9 Pass Invention Material 10 1/220/3 2.5 600 820 Good 98.1 Pass Invention Material 11 3/220/2 2.3 600 820 Good 99.2 Pass Comparative material 3 1/220 / 0.5 1.6 600 820 Good 99.3 Fail Comparative material 4 3/220/3 2.7 450 770 Good 78.8 Fail Comparative material 5 3/220/3 2.7 900 820 Good 82.5 Pass Comparative Material 6 3/220/3 2.7 600 700 Good 79.2 Fail Invention Material 12 3/220/3 2.7 700 900 Good 97.8 Pass

As shown in Table 1, in the case of the inventive material (1-12) according to the present invention, it can be seen that the shape of the molded body is good, the metallization rate is high, and the fracture of the sample does not occur during the compressive strength test. .

On the contrary, when the water content is higher than the range of the present invention (Comparative Material 1), the molding density decreases and residues remain in the molding machine, which makes it difficult to release the mold (a process in which the molded body falls from the molding machine), which causes the molded body to be judged. .

In addition, when the particle size of the dried sludge is larger than the range of the present invention (Comparative Material 2), the molding density is uneven, rather the molding density does not increase, the metallization rate is low, and the judgment occurs in the compressive strength test. As the particle size becomes smaller, the molding density decreases. Therefore, if the fine pulverization is less than the original particle size is reduced, the density of the molded body and the final sintered body is reduced and the fracture may occur during the compressive strength test, it is recommended not to severely grind.

It is difficult to achieve a compressive strength of 100 Kg / mm ² when finely pulverized so that the particle size is 30 micrometers or less.

The sample size is milled to 35 microns, as in the invention, but the compression strength of material 4 is 100Kg / mm ² is obtained, it is difficult to secure the 150Kg / mm ^2.

In addition, when the molded body density is smaller than the range of the present invention (Comparative Materials 1, 3), breakage occurs during subsequent heat treatment, or after the reduced sintering, the compacted body density is also reduced and the target compressive strength is 100 Kg / cm ² or more, preferably 150 Kg / cm ^2. It was confirmed that no abnormality was obtained.

In addition, when the density of the compact before reduction is greater than the range of the present invention (Comparative Material 2), it is difficult to penetrate the reducing gas, so that reduction, that is, metallization rate (metallization rate = Fe + Ni content of the reduced sample, ratio of Fe: Ni It can be seen that the average is 2: 1) in the sample.

In addition, when the primary reduction temperature and the sintering temperature during reduction are lower than the range of the present invention (Comparative Materials 4 and 6), the metallization rate is low, and it can be seen that the fracture occurs during the compressive strength test.

In addition, it can be seen that when the reduction start temperature is higher than the range of the present invention (Comparative Material 5), the metallization rate is low.

(Example 2)

The dechlorination was carried out by heating and calcining at the dechlorination temperature condition shown in Table 2 for 1 hour.

At this time, the pre-dechlorination powder did not undergo a calcining process separately because water was removed when Cl was removed.

De-Cl treated sludge powder as described above according to the method of Example 1 to produce a Fe-Ni ingot.

At this time, the molding conditions and the reduction temperature were as shown in Table 2.

As described above, the purity and Ni content of the prepared Fe-Ni alloy ingot was measured by ICP, and the results are shown in Table 2 below.

Sample No. Molding conditions Reduction temperature (℃) Dechlorination Temperature (℃) Fe + Ni concentration (% by weight) Ni content (% by weight) Particle Size (㎛) / Forming Force (Ton) Density (g / cc) 1st reduction Secondary reduction (reduction sintering) Comparative material 7 240/3 2.8 600 820 550 94.1 31 Invention Material 13 190/3 2.5 600 820 650 96.8 32 Invention Material 14 110/3 2.4 600 820 750 98.1 33 Invention Material 15 350/3 2.6 600 820 850 99.3 33 Comparative Material 8 340/3 2.7 600 820 950 99.4 27

As shown in Table 2, when the dechlorination heat treatment temperature is less than 600 ℃ (Comparative Material 7), the dechlorination reaction is not good, the total purity of the alloy ingot with poor chlorine, the dechlorination temperature is 950 ℃ In the case of exceeding (Comparative Material 8), Ni content, which is an expensive component, may be reduced due to volatilization of NiCl ₂ .

(Example 3)

Fe-Ni alloy ingot was prepared in the same manner as Inventive Material (14) of Example 2, except that molasses, which is an organic carbon compound decomposed upon heat treatment, as shown in Table 3 for improving moldability before forming a molded article. , By adding stearic acid (Inventive material 16 and 17, and Comparative material 9), the effect of increasing the density and the purity was investigated, the results are shown in Table 3 below.

Sample No. Molding conditions Reduction temperature (℃) Dechlorination Temperature (℃) Fe + Ni concentration (% by weight) Residual Carbon (wt%) Formability improver Density (g / cc) Primary reduction Secondary Reduction (Reduction Sintering) Invention Material 14 No addition 2.5 600 820 750 98.1 0.015 Invention Material 16 Stearic Acid 2% 2.8 600 820 650 97.8 0.25 Invention Material 17 Molasses 4% 2.9 600 820 750 98.1 0.55 Comparative material 9 15% molasses 4.6 600 820 850 89.3 3.65

As shown in Table 3, it can be seen that in the case where an appropriate amount of molasses and stearic acid is added to improve moldability (inventive material 16) and (inventive material 17), the molded body density is increased and the moldability is improved.

However, it can be seen that when the amount of the moldability improving agent is too large (Comparative Material 9), excessive carbon is not generated due to excessive increase in density and residual carbon is generated.

(Example 4)

FeNi-containing sludge generated from FeCl ₃ etching solution recycling process was dissolved in water, neutralized by adding sodium hydroxide (NaOH) to the solution containing this sludge at pH = 10.5, and then filtering the sludge with solid-liquid separator in aqueous solution. Was further added to wash the sludge to remove NaCl, an aqueous neutralizing salt. The de Cl-treated FeNi sludge obtained through the above process was pulverized by drying the sludge dried with a water content of 1% or less by a ball mill to obtain a powder having a particle size of 110㎛. The powder was charged into a pan of a rotating spherical ingot manufacturing apparatus, and water or water and PVA were added at the addition ratios shown in Table 4 below to prepare pellets having different densities.

After drying the spherical mass to control the water content to 1% or less and calcined at 700 ℃, after reducing in a reducing furnace under the reduction temperature conditions of Table 4, the shape, purity and carbon residues were measured, and the results Table 4 shows.

Sample No. Molding conditions Reduction temperature (℃) Fe + Ni concentration (% by weight) Residual carbon (wt%) Remarks Additives (addition amount) Density (g / cc) Primary reduction Secondary Reduction (Reduction Sintering) Comparative Material 10 Water 3% 1.5 600 820 98.8 0.008 Mold density failure failure Invention Material 18 8% water, 2% PVA 2.8 600 820 98.4 0.36 - Invention 19 15% water, 1% PVA 2.9 600 820 98.2 0.15 - Comparative Material 11 30% water, 6% PVA 3.62 600 820 91.3 2.78 -

As shown in Table 4, when the amount of water added is less than 5% (Comparative Material 10), the density of the spherical ingot is low, so it can be seen that poor compressive strength and rupture occur during the treatment, and that the amount of water and the binder is too high. In the case of (Comparative Material 11), it is understood that the amount of residual carbon is high, and the purity is also low due to unreduced.

In contrast, when water and a binder (PVA) were added according to the present invention (inventive materials 18 and 19), the metallization rate was high and the amount of residual carbon was low.

  According to the present invention, since the FeNi alloy ingot having excellent strength and high purity can be produced more economically, the present invention has an effect that can be suitably applied to the field of FeNi-containing sludge generation.

Claims (16)

Neutralizing the FeNi-containing sludge with a neutralizing agent and drying the sludge from which chlorine was removed to a moisture content of 5% or less; Pulverizing the dried sludge to have an average particle size of 30-700㎛; Molding the pulverized powder as described above to have a molding density in the range of 1.7-4.7 g / cc; Heating the molded article molded as described above at a heating rate of 100 ° C./min or less and baking at 500-950 ° C .; The calcined product as described above is first reduced for 15-60 minutes at a temperature range of 500-750 ° C. under a reducing gas atmosphere and subjected to secondary reduction heat treatment for 15-60 minutes at a temperature range of 750-1000 ° C. during reduction. Heat-treating the sintering reaction to occur; And Method for producing an iron nickel alloy ingot using iron nickel-containing sludge, characterized in that it comprises the step of cooling the reduced sintered alloy ingot The iron using iron nickel-containing sludge according to claim 1, wherein the FeNi-containing sludge is FeNi-containing sludge which is a secondary waste generated in the process of recycling the etching waste liquid generated in the shadow mask manufacturing process of an electronics company. Manufacturing method of nickel alloy ingot The method for producing an iron nickel alloy ingot using iron nickel-containing sludge according to claim 1 or 2, wherein the neutralizing agent is one selected from the group consisting of NaOH, Ca (OH) ₂ , and Na ₂ CO ₃ . The method according to claim 1 or 2, wherein a moldability improving agent is added to the pulverized powder before molding, and the moldability improving agent is one or two or more selected from the group consisting of molasses, stearic acid, and fatty acids. Method for producing iron nickel alloy ingot using iron nickel-containing sludge The method for producing an iron nickel alloy ingot using iron nickel-containing sludge according to claim 1 or 2, wherein the pulverized powder is calcined, molded, and then subjected to reduction heat treatment. The water-forming method according to claim 1 or 2, wherein the molding method is a press molding method or a spherical block forming method, and when the molding method is a spherical block forming method, 5-30% by weight of water or 5-30% by weight of water is used. And a method of producing an iron nickel alloy ingot using iron nickel-containing sludge, characterized by carrying out a drying process of removing water after adding and bulking (molding) up to 5% by weight of PVA together. The iron nickel alloy using iron nickel-containing sludge according to claim 1 or 2, wherein the reducing gas is one gas selected from a group of reducing gases consisting of hydrogen, carbon monoxide and ammonia, or a mixture thereof. Ingot Production Method The method for producing an iron nickel alloy ingot using iron nickel-containing sludge according to claim 7, wherein the reducing gas is a hydrogen-containing gas. The method for producing an iron nickel alloy ingot using iron nickel-containing sludge according to claim 1 or 2, wherein molding of the pulverized powder is performed so that the density of the molded body is in the range of 2.0-3.5 g / cc. Calcining the FeNi-containing sludge at a heat treatment temperature of 600-900 ° C. to remove chlorine and water; Pulverizing the calcined sludge to have a particle size of 30-700 μm; Molding the pulverized powder as described above to have a molding density in the range of 1.7-4.7 g / cc; Heat-treating the compacted body under reducing gas atmosphere for 15-60 minutes at a temperature range of 500-750 ° C. and for secondary reduction heat treatment for 15-60 minutes at a temperature range of 750-1000 ° C. step; And Method for producing iron nickel alloy ingot using iron nickel (FeNi) containing sludge, characterized in that it comprises the step of cooling the reduced sintered alloy ingot The iron using iron nickel-containing sludge according to claim 10, wherein the FeNi-containing sludge is FeNi-containing sludge, which is a secondary waste generated in a process of recycling an etching waste liquid generated in an electronics company shadow mask manufacturing process. Manufacturing method of nickel alloy ingot The method according to claim 10 or 11, wherein a moldability improving agent is added to the pulverized powder before molding, and the moldability improving agent is one or two or more selected from the group consisting of molasses, stearic acid, and fatty acids. Method for producing iron nickel alloy ingot using iron nickel-containing sludge 12. The method according to claim 10 or 11, wherein the molding method is a press molding method or a spherical block forming method, and when the molding method is a spherical block forming method, 5-30% by weight of water or 5-30% by weight of water with respect to the powder. And a method of producing an iron nickel alloy ingot using iron nickel-containing sludge, characterized by carrying out a drying process of removing water after adding and bulking (molding) up to 5% by weight of PVA together. The iron nickel alloy ingot using iron nickel-containing sludge according to claim 10 or 11, wherein the reducing gas is one gas selected from a group of reducing gases consisting of hydrogen, carbon monoxide and ammonia, or a mixture thereof. Manufacturing method 15. The method for producing an iron nickel alloy ingot using iron nickel-containing sludge according to claim 14, wherein the reducing gas is a hydrogen-containing gas. 12. The method for producing an iron nickel alloy ingot using iron nickel-containing sludge according to claim 10 or 11, wherein the shaping of the pulverized powder is performed so that the density of the compact is in the range of 2.0-3.5 g / cc.