KR102057976B1 - Refining method for sulfuric acid sludge - Google Patents

Abstract

The present invention relates to a sulfuric acid sludge refining method. More specifically, provided is a sulfuric acid sludge refining method which comprises the following steps: (a) drying sulfuric acid sludge; (b) pulverizing the dried sulfuric acid sludge; (c) calcinating the finely pulverized sulfuric acid sludge to form a calcinated product from which sulfur (S) components are separated; (d) recovering the compound containing titanium by performing specific gravity selection or flotation selection of the calcinated product; and (e) recovering titanium dioxide from the titanium-containing compound via a sulfuric acid method.

Description

Sulfuric acid sludge refining method {REFINING METHOD FOR SULFURIC ACID SLUDGE}

The present invention relates to a sulfuric acid sludge refining method capable of separating the sulfur (S) component from the sulfuric acid sludge generated during the production of titanium dioxide by the sulfate process, and recovering titanium dioxide.

Titanium dioxide (TiO ₂ ) is a multifunctional oxide material having nontoxicity, excellent chemical stability, high light refractive index, and the like. Titanium dioxide has three crystal structures: rutile, anatase and brookite. Titanium dioxide is predominant in white pigments because of its excellent chemical stability and high hiding power. It is widely used in paints, paper, rubber, plastics, ceramics, etc. In addition, titanium dioxide is widely used in high refractive index ceramics because of its high refractive index, and is widely used as a raw material for toothpaste, cosmetics, and medicines because it is a non-toxic material, and has photocatalytic properties and superhydrophilic properties. Crystal grain size, morphology, phase composition, surface morphology, and mixing with other components of titanium dioxide affects the properties and functions of titanium dioxide.

Currently, commercially distributed titanium dioxide is largely divided into rutile and anatase, and its use is classified or used in combination. In addition, it is expected that the production and consumption of high value-added products will increase rapidly because they are developed and applied in various ways by using the nano form.

Generally, there are three methods for producing titanium dioxide: sulfuric acid method, hydrochloric acid method, and sol-gel method.

Among these, sulfuric acid method (1) dissolving titanium slag or natural ilmenite (FeTiO ₃ ) ore with sulfuric acid to obtain a titanium sulfate solution, (2) adding waste iron or waste aluminum to the titanium sulfate solution Chemical reduction of ferric ions contained as impurities in the solution to a divalent (ferrous) state prevents iron precipitation, increases the degree of bleaching of the titanium dioxide product, and then cools the solution to form iron sulfate (II ) Precipitated and removed, (3) heat-hydrolyzing the titanium sulfate solution from which iron (II) sulfate has been removed, followed by precipitating hydrous titanium dioxide, followed by filtration and washing, and (4) washing The hydrous titanium dioxide is calcined at 800 to 1,000 ° C. to obtain anhydrous titanium dioxide.

The sulfuric acid method for producing titanium dioxide from ilmenite generates a large amount of sulfuric acid sludge. The sulfuric acid sludge contains 32.3% TiO ₂ , 15% SiO ₂ , 13.5% Fe ₂ O ₃ , 1.7% MgO, 17.8% Ignition loss, 14.5% SO ₃ , and the like. Sulfuric acid sludge is disposed of as a waste and is treated, but since sulfuric acid sludge contains about 10% or more of sulfur, the treatment is very difficult.

The existing landfill method for treating such sulfuric acid sludge requires a neutralizing agent, and there is a high risk of leachate due to sulfur (S) and iron (Fe), and more than 30% of TiO ₂ is lost in terms of raw material utilization. In this situation, a specific recovery plan is needed.

Prior art related to this is a method of smelting titanium dioxide using ilmenite disclosed in Korean Patent Publication No. 10-1790128.

Republic of Korea Patent Publication No. 10-1790128 (August 26, 2017)

The present invention is to provide a sulfuric acid sludge refining method that can effectively recover sulfuric acid and titanium dioxide from sulfuric acid sludge generated during the production of titanium dioxide by the sulfate process.

The problem to be solved by the present invention is not limited to the problem (s) mentioned above, and other object (s) not mentioned will be clearly understood by those skilled in the art from the following description.

In order to solve the above problems, the present invention comprises the steps of drying the sulfuric acid sludge (step a); Pulverizing the dried sulfuric acid sludge (step b); Roasting the finely divided sulfuric acid sludge to form a roasted product in which the sulfur (S) component is separated (step c); Recovering the compound containing titanium by performing specific gravity or flotation on the roasted product (d step); And recovering titanium dioxide from the titanium-containing compound through a sulfuric acid method (step e).

In addition, the present invention comprises the steps of drying the sulfuric acid sludge (first step); Pulverizing the dried sulfuric acid sludge (second step); Roasting the finely divided sulfuric acid sludge, oxidizing the sulfur (S) component contained in the sulfuric acid sludge to produce a sulfur (S) component gas, and separating the produced sulfur (S) component gas using a separate apparatus (Third step); Forming a roasted product in which the sulfur (S) component is separated (fourth step); It provides a sulfuric acid sludge refining method comprising a; (Stage 5) preparing sulfuric acid by absorbing the sulfur (S) component gas separated by the separate device in water.

The sulfuric acid sludge may be dried for 1 to 24 hours at 100 to 200 ℃.

The dried sulfuric acid sludge may be finely ground to a particle size of 44 μm or less.

The roasting may be performed for 1 to 10 hours at 400 to 1,200 ° C. under air or oxygen atmosphere.

The roasting may be performed in a rotary kiln or a fluidized bed roaster.

The sulfuric acid sludge may include one or more selected from the group consisting of TiO ₂ , MgSiO ₃ , FeSO _{4 ·} 7H ₂ O, FeTiO _3, and (TiO) SO ₄ .

The roast product may include one or more selected from the group consisting of TiO ₂ , MgSiO ₃ , Fe ₂ O _3, and Fe ₂ TiO ₅ .

The titanium-containing compound may be Fe ₂ TiO ₅ .

The specific gravity screening is performed in a shaking table under a condition of water supply of 4 to 10 L / min, roasting product input of 200 to 350 g / min, and tilt of 1.5 to 3 degrees, thereby containing titanium-containing compounds. It may be to recover.

The flotation may be to recover the compound containing titanium as a Denver sub-A flotation sorter by adding a catcher to the roasted product and stirring, and then adding a foaming agent.

The recovered titanium dioxide may be in the range of 50 to 90%.

The sulfur (S) component gas may be SO ₂ gas or SO ₃ gas.

The separate device may be an electric precipitator or a bag filter.

According to the present invention, by roasting sulfuric acid sludge generated in the production of titanium dioxide by the sulfate process (Sulfate process) it can be produced a roasted product from which the sulfur component is removed or separated.

In addition, sulfur components may be prepared by oxidizing the removed or separated sulfur component into a sulfur component gas and absorbing it into water.

In addition, it is possible to recover the compound containing titanium from the roasted product from which the sulfur component is removed or separated by roasting the sulfuric acid sludge, and the recovered titanium containing compound can be produced not only by titanium dioxide, but also in circulation. As a resource, it can directly contribute to the reduction of ilmenite raw material imports.

The effects of the present invention are not limited to the above-described effects, but should be understood to include all the effects deduced from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a process flow diagram showing a sulfuric acid sludge refining method according to an embodiment of the present invention.
Figure 2 is a process flow diagram showing a sulfuric acid sludge refining method according to another embodiment of the present invention.
3 is an XRD graph of sulfuric acid sludge in the sulfuric acid sludge refining method according to an embodiment of the present invention.
4 is an XRD graph of roasted products after roasting in the sulfuric acid sludge refining method according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Advantages and features of the present invention, and a method of achieving the same will be apparent with reference to the embodiments described below in detail with reference to the accompanying drawings.

However, the present invention is not limited by the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments make the disclosure of the present invention complete, and those skilled in the art to which the present invention pertains. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims.

In addition, in the following description of the present invention, if it is determined that related related technologies and the like may obscure the gist of the present invention, detailed description thereof will be omitted.

1 is a process flow diagram showing a sulfuric acid sludge refining method according to an embodiment of the present invention.

1, the sulfuric acid sludge refining method according to an embodiment of the present invention comprises the steps of drying the sulfuric acid sludge (step a); Pulverizing the dried sulfuric acid sludge (step b); Roasting the finely divided sulfuric acid sludge to form a roasted product in which the sulfur (S) component is separated (step c); Recovering the compound containing titanium by performing specific gravity or flotation on the roasted product (d step); And recovering titanium dioxide from the titanium-containing compound through a sulfuric acid method (step e).

First, sulfuric acid sludge refining method according to an embodiment of the present invention is dried sulfuric acid sludge (S10).

The sulfuric acid sludge may be sulfuric acid sludge generated during the production of titanium dioxide by a conventional sulfate process.

Specifically, the sulfuric acid sludge according to the present invention may include at least one selected from the group consisting of TiO ₂ , MgSiO ₃ , FeSO _{4 ·} 7H ₂ O, FeTiO _3, and (TiO) SO ₄ .

The sulfuric acid sludge may be dried at 100 to 200 ° C. for 1 to 24 hours, and it is preferable to completely dry the sulfuric acid sludge for the temperature range of 100 to 200 ° C. and 1 to 24 hours. When the sulfuric acid sludge is dried during the temperature range and time, the sulfuric acid sludge may be prevented from condensing the sulfuric acid sludge during the oxidation roasting to improve the efficiency of the roasting reaction.

On the other hand, when the sulfuric acid sludge is not completely dried, there is a problem that it is not easy to prepare the sulfuric acid sludge in the form of fine powder.

Next, the dried sulfuric acid sludge is pulverized (S20).

By pulverizing the dried sulfuric acid sludge, it is possible to prevent the sulfuric acid sludge from condensing when the dried sulfuric acid sludge is roasted, thereby improving the efficiency of the roasting reaction.

The dried sulfuric acid sludge may be pulverized to an average particle size of 44 μm or less, specifically 10 to 44 μm.

If the average particle size of the dried sulfuric acid sludge is less than 10 μm or more than 44 μm, specific gravity or flotation is not easy. Particularly, when the average particle size of the dried sulfuric acid sludge is less than 10 μm, the particles are affected by water flow. As a result, it may be difficult to select specific gravity.

Next, the roasted sulfuric acid sludge is roasted to form an roasted product in which the sulfur (S) component is separated or removed (S30).

The roasting may be performed in a rotary kiln or in a fluidized bed roaster.

The roasting may be performed under air or oxygen atmosphere, and specifically, may be performed under oxygen atmosphere to increase the reaction rate.

When roasted under the air or oxygen atmosphere, sulfur (S) component contained in pulverized sulfuric acid sludge is oxidized to produce sulfur (S) component gas, and sulfur (S) component is separated from pulverized sulfuric acid sludge. The product can be formed.

At this time, the produced sulfur (S) component gas can be separated by a separate device.

The separate device may be an electric precipitator or a bag filter.

The sulfur (S) component gas may be an SO ₂ gas or an SO ₃ gas.

The roasting may be roasted within a temperature range of 400 to 1,200 ℃, specifically 500 to 1,000 ℃.

When roasting the pulverized sulfuric acid sludge is less than 400 ℃ reaction rate may be too low, when the roasting temperature of the pulverized crushed sulfuric acid sludge is more than 1,200 ℃ intergranular melting phenomenon occurs As a result, clogging to roasting may occur.

The roasting of the pulverized sulfuric acid sludge may be roasted for 1 to 10 hours, specifically 1 to 3 hours.

When roasting the pulverized sulfuric acid sludge, the roasting reaction may be insufficient if less than 1 hour, roasting time when roasting the pulverized sulfuric acid sludge, energy efficiency may be lowered if it exceeds 10 hours. .

The roasted product in which sulfur (S) component is separated by roasting the finely divided sulfuric acid sludge may include at least one selected from the group consisting of TiO ₂ , MgSiO ₃ , Fe ₂ O _3, and Fe ₂ TiO ₅ .

Next, the roasted product is subjected to specific gravity screening or suspension screening to recover the compound containing titanium (S40).

The specific gravity screening may recover a compound containing titanium from the roasted product using a shaking table device.

Specifically, the specific gravity selection is 4 to 10 L / min water supply, 200 ~ 350 g / min roasted product input, containing the titanium from the roasted products through the vibration table under the vibration table 1.5 to 3 degrees Recovered compounds can be recovered. When the specific gravity screening is performed under the above conditions, a compound containing titanium may be selectively recovered from the roasted product.

The flotation can recover the compound containing titanium from the roasted products according to the size and composition of the particles.

The flotation can be used to recover the compound containing titanium from the roasted product using a Denver sub-A type flotation.

Specifically, in the flotation, hydrophobization of the roasted product is carried out by adding a catcher to the roasted product, followed by stirring. To recover the titanium-containing compound from the roasted product.

In this case, the catcher is an amine-based catcher, the foaming agent may be used AF 65 foaming agent. When performing flotation using the catcher and the foaming agent, a compound containing titanium may be selectively recovered from the roasted product.

As a result of the specific gravity screening or floating screening of the roasted product, the compound containing titanium may be Fe ₂ TiO ₅ .

Next, recover the titanium dioxide from the compound containing titanium through the sulfuric acid method (S50).

The titanium dioxide may be recovered from the compound containing titanium through a conventional sulfuric acid method.

At this time, the recovered titanium dioxide may be 50 to 90% quality.

On the other hand, Figure 2 is a process flow diagram showing a sulfuric acid sludge refining method according to another embodiment of the present invention.

2, the sulfuric acid sludge refining method according to another embodiment of the present invention comprises the steps of drying the sulfuric acid sludge (first step); Pulverizing the dried sulfuric acid sludge (second step); Roasting the finely divided sulfuric acid sludge, oxidizing the sulfur (S) component contained in the sulfuric acid sludge to produce a sulfur (S) component gas, and separating the produced sulfur (S) component gas using a separate apparatus (Third step); Forming a roasted product in which the sulfur (S) component is separated (fourth step); And preparing sulfuric acid by absorbing the sulfur (S) component gas separated by the separate device into water.

Sulfuric acid sludge refining method according to another embodiment of the present invention is dried sulfuric acid sludge (S100).

S100 may be performed under the same method and conditions as S10 described above to dry sulfuric acid sludge.

Specifically, the sulfuric acid sludge may include one or more selected from the group consisting of TiO ₂ , MgSiO ₃ , FeSO _{4 ·} 7H ₂ O, FeTiO ₃ and (TiO) SO ₄ , wherein the sulfuric acid sludge is 100 to 200 ° C. Can be dried for 1 to 24 hours. When the sulfuric acid sludge is dried during the temperature range and time, the sulfuric acid sludge may be prevented from condensing the sulfuric acid sludge during the oxidation roasting to improve the efficiency of the roasting reaction.

On the other hand, when the sulfuric acid sludge is not completely dried, there is a problem that it is not easy to prepare the sulfuric acid sludge in the form of fine powder.

Next, the dried sulfuric acid sludge is pulverized (S200).

The S200 may be carried out under the same method and conditions as the above-described S20 to pulverize the dried sulfuric acid sludge.

Specifically, the dried sulfuric acid sludge may be finely pulverized to an average particle size of 44 μm or less, specifically 10 to 44 μm.

If the average particle size of the dried sulfuric acid sludge is less than 10 μm or more than 44 μm, specific gravity or flotation is not easy. Particularly, when the average particle size of the dried sulfuric acid sludge is less than 10 μm, the particles are affected by water flow. As a result, it may be difficult to select specific gravity.

Next, the pulverized sulfuric acid sludge is roasted to oxidize the sulfur (S) component contained in the sulfuric acid sludge to produce a sulfur (S) component gas, and using the prepared sulfur (S) component gas using a separate device. Separate (S300).

The S300 may be performed under the same method and conditions as the above-described S30 to roast the pulverized sulfuric acid sludge.

The roasting may be performed in a rotary kiln or in a fluidized bed roaster.

Specifically, the roasting may be carried out in a temperature range of 400 to 1,200 ℃, more specifically 500 to 1,000 ℃. When roasting the pulverized sulfuric acid sludge is less than 400 ℃ reaction rate may be too low, when the roasting temperature of the pulverized crushed sulfuric acid sludge is more than 1,200 ℃ intergranular melting phenomenon occurs As a result, clogging to roasting may occur.

In addition, the roasting may be performed for 1 to 10 hours, more specifically for 1 to 3 hours. When roasting the pulverized sulfuric acid sludge, the roasting reaction may be insufficient if less than 1 hour, roasting time when roasting the pulverized sulfuric acid sludge, energy efficiency may be lowered if it exceeds 10 hours. .

The S300 is performed under the same method and conditions as the S30 to roast the pulverized sulfuric acid sludge under an air or oxygen atmosphere, and the sulfur (S) component contained in the pulverized sulfuric acid sludge is oxidized, thereby sulfur (S) component gas. Is prepared, and the produced sulfur (S) component gas may be separated by a separate device.

The separate device may be an electric precipitator or a bag filter.

The sulfur (S) component gas may be an SO ₂ gas or an SO ₃ gas.

Next, the sulfur (S) component to form an isolated roast product (S400).

The roasted product from which the sulfur (S) component is separated may be a roasted product from which the sulfur (S) component is separated by separating the sulfur (S) component gas prepared in S300 by using a separate device.

At this time, the sulfur (S) component of the roast product is separated may include one or more selected from the group consisting of TiO ₂ , MgSiO ₃ , Fe ₂ O ₃ and Fe ₂ TiO ₅ .

Next, sulfuric acid is prepared by absorbing the sulfur (S) component gas separated by the separate device in water (S500).

At this time, the sulfuric acid may be prepared in 50% or more, specifically 50 to 100% sulfuric acid solution.

The present invention may be used to recover the titanium dioxide from the compound containing titanium in the above-described S50, specifically, the sulfuric acid method through the sulfuric acid solution prepared as described above.

Meanwhile, the sulfuric acid sludge refining method according to the present invention comprises the steps of drying the sulfuric acid sludge (step a); Pulverizing the dried sulfuric acid sludge (step b); Roasting the finely divided sulfuric acid sludge to form a roasted product in which the sulfur (S) component is separated (step c); Recovering the compound containing titanium by performing specific gravity or flotation on the roasted product (d step); And recovering titanium dioxide from the titanium-containing compound through a sulfuric acid method (step e); but oxidizing the sulfur (S) component contained in the sulfuric acid sludge when roasting the finely divided sulfuric acid sludge in step c. Sulfur (S) component gas is prepared, and the produced sulfur line gas is separated by a separate device, and the sulfur (S) component is separated by a separate device while forming a roasted product. Sulfuric acid can be prepared by absorbing the component gas into water.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

Production Example

Sulfuric acid sludge was obtained through a conventional sulfuric acid method of producing titanium dioxide (TiO ₂ ) from ilmenite (FeTiO ₃ ).

Example

Example 1

2 kg of sulfuric acid sludge obtained in the preparation was completely dried at 200 ° C. for 24 hours.

The dried sulfuric acid sludge was ground to an average particle size of 44 μm using a Corn mill apparatus.

The pulverized sulfuric acid sludge was oxidized and roasted at 1000 ° C. for 3 hours under an oxygen atmosphere to separate sulfur dioxide gas generated during oxidation of sulfuric acid sludge with an electrostatic precipitator, an exhaust gas treatment facility, to form a roasted product.

The roasted products were gravity-selected through a vibrating table to recover Fe ₂ TiO ₅ under a condition that a water supply amount of 7 L / min, a roast product amount of 300 g / min, and a table inclination were 2 degrees.

The Fe ₂ TiO ₅ was recovered as titanium dioxide and sulfuric acid sludge, respectively, by the sulfuric acid method, wherein the grade of titanium dioxide was 60%.

Example 2

2 kg of sulfuric acid sludge obtained in the preparation was completely dried at 200 ° C. for 24 hours.

The dried sulfuric acid sludge was ground to an average particle size of 44 μm using a Corn mill apparatus.

The pulverized sulfuric acid sludge was oxidized and roasted at 1000 ° C. for 3 hours under an oxygen atmosphere to separate sulfur dioxide gas generated during oxidation of sulfuric acid sludge with an electrostatic precipitator, an exhaust gas treatment facility, to form a roasted product.

An amine-based catcher was added to the roasted product, followed by stirring, and then AF 65 foaming agent was added and suspended by a Denver sub-A type floating separator to recover Fe ₂ TiO ₅ .

The Fe ₂ TiO ₅ was recovered as titanium dioxide and sulfuric acid sludge, respectively, by the sulfuric acid method, wherein the grade of titanium dioxide was 60%.

Example 3

2 kg of sulfuric acid sludge obtained in the preparation was completely dried at 200 ° C. for 24 hours.

The dried sulfuric acid sludge was ground to an average particle size of 44 μm using a Corn mill apparatus.

The pulverized sulfuric acid sludge was oxidized and roasted at 1000 ° C. for 3 hours under an oxygen atmosphere to separate sulfur dioxide gas generated during oxidation of sulfuric acid sludge with an electrostatic precipitator, an exhaust gas treatment facility, to form a roasted product.

Sulfur dioxide gas separated by an exhaust gas treatment facility such as the electrostatic precipitator was absorbed into water to prepare a sulfuric acid solution having a concentration of 60%.

At this time, the roasted products were subjected to specific gravity selection of the roasted products under the same conditions and methods as in Example 1 to recover Fe ₂ TiO ₅ .

The Fe ₂ TiO ₅ was recovered as titanium dioxide and sulfuric acid sludge, respectively, by the sulfuric acid method, wherein the grade of titanium dioxide was 60%.

Experimental Example

Experimental Example 1

The sulfuric acid sludge prepared in Preparation Example and the components of roasted products after roasting in Examples 1 to 2 were analyzed by energy dispersive X-ray fluorescence spectroscopy, and the results are shown in Table 1 below.

TiO ₂
(%) Fe ₂ O ₃
(%) SiO ₂
(%) Al ₂ O ₃
(%) CaO
(%) SO ₃
(%) Intensity
outage
(%) Other
(%) Preparation Example 1 32.3 17 15 - 0.5 15 17.8 2.4 Example 1 60 20 13 2 One - - 4 Example 2 60 10 20 5 - - - 5 Example 3 60 20 13 2 One - - 4

Referring to Table 1, it was confirmed that the sulfur component was removed from the roast product formed after roasting.

Experimental Example 2

The sulfuric acid sludge prepared in Preparation Example and the roasted product after roasting oxide prepared in Example 1 were measured using an X-ray diffractometer (Bruker AXS D4-Endeavor XRD), and the results are shown in FIGS. 3 and 4. It was.

3 is an XRD graph of sulfuric acid sludge in the sulfuric acid sludge refining method according to an embodiment of the present invention, Figure 4 is a XRD graph of roasted products after roasting in the sulfuric acid sludge refining method according to an embodiment of the present invention.

Referring to FIG. 3, it can be seen that FeSO ₄ and TiOSO _{4, which} are sulfur-containing compounds, exist. Referring to FIG. 4, after roasting, Fe ₂ O ₃ and Fe ₂ TiO ₅ are present in the roasted products. It can be confirmed that the sulfur component is removed.

Although specific embodiments of the sulfuric acid sludge refining method according to the present invention have been described so far, it is obvious that various embodiments can be modified within the scope of the present invention.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

In other words, the above-described embodiments are to be understood in all respects as illustrative and not restrictive, the scope of the invention being indicated by the following claims rather than the detailed description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be construed as being included in the scope of the present invention.

Claims (14)

Drying sulfuric acid sludge comprising at least one selected from the group consisting of TiO ₂ , MgSiO ₃ , FeSO ₄ .7H ₂ O, FeTiO _3, and (TiO) SO ₄ (step a);
Pulverizing the dried sulfuric acid sludge (step b);
Roasting the finely divided sulfuric acid sludge to form a roasted product in which the sulfur (S) component is separated (step c);
Recovering the compound containing titanium by performing specific gravity or flotation on the roasted product (d step); And
A method of refining sulfuric acid sludge comprising the step of (e) recovering titanium dioxide from a compound containing titanium through a sulfuric acid method.
Drying a sulfuric acid sludge comprising at least one selected from the group consisting of TiO ₂ , MgSiO ₃ , FeSO ₄ .7H ₂ O, FeTiO _3, and (TiO) SO ₄ (first step);
Pulverizing the dried sulfuric acid sludge (second step);
Roasting the finely divided sulfuric acid sludge, oxidizing the sulfur (S) component contained in the sulfuric acid sludge to produce a sulfur (S) component gas, and separating the produced sulfur (S) component gas using a separate apparatus (Third step);
Forming a roasted product in which the sulfur (S) component is separated (fourth step); And
Sulfuric acid sludge refining method comprising the step of absorbing sulfur (S) component gas separated by the separate device in water to produce sulfuric acid (stage 5).
The method according to claim 1 or 2,
The sulfuric acid sludge refining method is dried for 1 to 24 hours at 100 to 200 ℃.
The method according to claim 1 or 2,
The dried sulfuric acid sludge is finely pulverized sulfuric acid sludge refining method of 44 μm or less.
The method according to claim 1 or 2,
The roasting is sulfuric acid sludge refining method that is carried out for 1 to 10 hours at 400 to 1,200 ℃ under air or oxygen atmosphere.
The method according to claim 1 or 2,
The roasting is a sulfuric acid sludge refining method that is carried out in a rotary kiln (Rotary kiln) or a fluidized bed (Fluidized bed roaster).
delete The method according to claim 1 or 2,
The roasting product is sulfuric acid sludge refining method comprising at least one selected from the group consisting of TiO ₂ , MgSiO ₃ , Fe ₂ O ₃ and Fe ₂ TiO ₅ .
The method of claim 1,
The titanium-containing compound is Fe ₂ TiO ₅ sulfuric acid sludge refining method.
The method of claim 1,
The specific gravity screening is carried out in a shaking table under a condition that the water supply amount is 4 to 10 L / min, the roast product input is 200 to 350 g / min, the slope is 1.5 to 3 degrees, the compound containing titanium Sulfuric acid sludge refining method to recover.
The method of claim 1,
The flotation is a sulfuric acid sludge refining method for recovering the compound containing titanium with a Denver sub-A type flotation sorter by adding and stirring the catcher to the roasted product.
The method of claim 1,
The recovered titanium dioxide is a sulfuric acid sludge refining method of 50 to 90% grade.
The method of claim 2,
Sulfuric acid sludge refining method of the sulfur (S) component gas is SO ₂ gas or SO ₃ gas.
The method of claim 2,
The separate device is a sulfuric acid sludge refining method that is an electric precipitator or bag filter.

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