KR101788920B1 - Method for recovering magnesium oxide and and silicon oxide from steel making slag - Google Patents
Method for recovering magnesium oxide and and silicon oxide from steel making slag Download PDFInfo
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- KR101788920B1 KR101788920B1 KR1020150084478A KR20150084478A KR101788920B1 KR 101788920 B1 KR101788920 B1 KR 101788920B1 KR 1020150084478 A KR1020150084478 A KR 1020150084478A KR 20150084478 A KR20150084478 A KR 20150084478A KR 101788920 B1 KR101788920 B1 KR 101788920B1
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- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
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Abstract
The present invention relates to a method for recovering magnesium oxide and silica using iron slag, and more particularly, to a method for recovering magnesium oxide and silica using iron sulfate slag, A solid-liquid separation step of dissolving and filtering solid-liquid separation, a silica recovery step of recovering silica by reacting ammonia water with the filtrate separated through the solid-liquid separation step, washing and filtering the recovered silica through the silica recovery step A magnesium hydroxide recovery step of recovering magnesium hydroxide by reacting ammonia water with the solid matter separated through the solid-liquid separation step, and a sintering step of sintering the recovered magnesium hydroxide through the magnesium hydroxide recovery step.
The method of recovering magnesium oxide and silica using the steel slag described above can recover magnesium oxide and silica at low cost through the process of circulating ammonium fluoride and ammonia water and is environmentally friendly because the amount of generated wastewater is low.
Description
The present invention relates to a method for recovering magnesium oxide and silica using steel slag, and more particularly, to a process for recovering magnesium oxide and silica at low cost by circulating ammonium fluoride and ammonia water, And a method for recovering magnesium oxide and silica using environmentally friendly steel slag.
Ferronickel slag is a by-product that is produced in large quantities during the processing of ferronickel ore, which is a raw material of stainless steel, and the grade of nickel ore is low. Therefore, ferronickel slag, which is 30 times more than nickel production, Nickel slag occurs annually.
Wherein the ferro-nickel slag is a silicon dioxide (SiO 2) is 55 to 60% and the magnesium oxide (MgO) 32 to 37% of the main component, calcium (CaO), iron oxide (Fe 2 O 3) and aluminum oxide (Al 2 O 3 ) are contained in a small amount.
In general, ferronickel slag is recycled as raw materials for cement manufacturing, civil engineering materials, concrete aggregate, runway aggregate, and ferronickel slag substitute in advanced countries such as Japan and Canada, but it is not yet utilized in Korea.
In Korea, ferronickel slag is sometimes used as a lining material and aggregate for steelmaking processes. In recent years, studies have been actively carried out to effectively extract silica and magnesium, which are contained in ferronickel slag, effectively as resources .
Korean Patent Laid-Open Nos. 10-2010-0085265, 10-2010-0085599 and 10-2010-0085618 disclose processes for producing magnesium compounds and silica products including mechanical activation of slag through milling by a ball mill .
The mechanical activation of the ferronickel slag is primarily intended to modify the crystalline silica to an amorphous state in order to enhance the leaching of the slag by the acid, and to achieve a satisfactory leaching rate, the slag should be finely pulverized as much as possible to increase the reaction area do. However, in this case, the gelation phenomenon with the silica generated in the slag sedimentation is an inevitable problem, and there is a problem that it takes a long time to perform the solid-liquid separation by the silica gelation phenomenon.
In order to solve the above problems, Korean Patent Laid-Open Publication No. 10-2014-0123641 discloses a technique of reducing the solid-liquid separation time by preventing gelation of silica by administering a small amount of fluorine compound before and after the slag acid treatment, All of the patents use an excessive amount of acidic substance in order to increase the efficiency of extracting the target component from the slag and then use a large amount of alkali compound such as sodium hydroxide for neutralization in the process of treating the extracted magnesium chloride (MgCl 2 ) and silica However, as described above, the use of a large amount of the acidic substance and the alkali component has a problem of generating a large amount of wastewater.
An object of the present invention is to provide a process for recovering magnesium oxide and silica at a low cost through a process of circulating ammonium fluoride and ammonia water and a method for recovering magnesium oxide and silica using environmentally friendly steel slag since the amount of generated wastewater is low .
An object of the present invention is to provide a method for producing ammonium fluoride, which comprises an ammonium fluoride reaction step in which a steel iron slag is mixed with an ammonium fluoride compound, a solid-liquid separation step in which water is mixed with the mixture prepared through the ammonium fluoride reaction step, A step of recovering silica by reacting the separated filtrate with ammonia water, and a step of washing and filtering the recovered silica through the recovering step of silica. And a recovery method.
It is another object of the present invention to provide a method for producing ammonium fluoride, which comprises a reaction step of mixing an iron fluoride compound with an iron fluoride slag, a solid-liquid separation step in which water is mixed with the mixture prepared through the ammonium fluoride reaction step, A step of purifying the solid material separated through the solid-liquid separation step, a step of recovering magnesium hydroxide by reacting the purified solid material with the ammonia water through the solids purification step, and recovering the magnesium hydroxide recovered through the magnesium hydroxide recovery step And a sintering step of sintering the iron oxide slag, and a sintering step of sintering the iron oxide slag.
It is another object of the present invention to provide a method for producing ammonium fluoride, which comprises a reaction step of mixing an iron fluoride compound with an iron fluoride slag, a solid-liquid separation step in which water is mixed with the mixture prepared through the ammonium fluoride reaction step, A step of collecting the silica by reacting ammonia water with the filtrate separated through the solid-liquid separation step, a washing filtration step of washing and filtering the recovered silica through the silica recovery step, a step of separating the solid matter separated through the solid- And a sintering step of sintering the magnesium hydroxide recovered through the magnesium hydroxide recovery step, characterized by comprising the step of purifying the solid matter, the step of recovering the magnesium hydroxide by reacting the purified solid matter with the ammonia water through the solid- Oxidation using steel slag A method for recovering magnesium and silica may be achieved by providing.
According to a preferred feature of the present invention, the steel-making slag is crushed and sorted to have a particle size of 100 to 1,000 mu m.
According to a further preferred feature of the present invention, the ammonium fluoride compound is at least one selected from the group consisting of ammonium fluoride, ammonium fluoride, ammonium fluoride, ammonium monophosphate and tetraalkylammonium fluoride.
According to a further preferred feature of the present invention, the ammonium fluoride reaction step is performed by mixing 50 to 500 parts by weight of an ammonium fluoride compound with 100 parts by weight of iron-based slag.
According to an even more preferred feature of the present invention, the solid-liquid separation step comprises mixing 500 parts by weight to 2000 parts by weight of water with 100 parts by weight of the mixture prepared through the ammonium fluoride reaction step.
According to an even more preferred feature of the present invention, it is assumed that the ammonia water generated in the ammonium fluoride mixing step is used.
According to an even more preferred feature of the present invention, the ammonium fluoride compound generated in the silica recovery step and the magnesium hydroxide recovery step is reused in the ammonium fluoride reaction step after moisture is removed.
According to a further preferred feature of the present invention, the firing step is performed at a temperature of 700 to 2000 ° C.
The method of recovering magnesium oxide and silica using the steel slag according to the present invention is economical because the ammonium fluoride and ammonia water are circulated without any additional supply of acid or base components from the outside, Effect.
Also, by extracting the silica component in a liquid phase during solid-liquid separation, the problem of silica gel formation, which occurs when silica is extracted as a solid, is solved.
1 is a process diagram showing a method for recovering magnesium oxide and silica using steel slag according to the present invention.
2 is a flowchart illustrating a method of recovering silica using steel slag according to an embodiment of the present invention.
3 is a flowchart illustrating a method for recovering magnesium oxide using a steel slag according to another embodiment of the present invention.
4 is a flowchart illustrating a method of recovering magnesium oxide and silica using steel slag according to another embodiment of the present invention.
Hereinafter, preferred embodiments of the present invention and physical properties of the respective components will be described in detail with reference to the accompanying drawings. However, the present invention is not limited thereto, And this does not mean that the technical idea and scope of the present invention are limited.
The method for recovering magnesium oxide and silica using the iron-based slag according to the present invention comprises a step (S101) of ammonium fluoride reaction in which an iron fluoride compound is mixed with an iron fluoride slag, a step (S101) (S103) for recovering silica by reacting ammonia water with the filtrate separated through the solid-liquid separation step (S103), and a silica recovery step (S105) for recovering silica, (S104) which can recover silica through a washing filtration step (S107) for washing and filtering the recovered silica through the solid-liquid separation step (S105), a solid purification step (S104) for purifying the separated solid through the solid- A magnesium hydroxide recovery step (S105-1) for recovering magnesium hydroxide by reacting ammonia water with the purified solid through the solids purification step (S104); and Magnesium can be recovered through the calcination step S107-1 in which the recovered magnesium hydroxide is recovered through the magnesium hydroxide recovery step (S105-1).
The ammonium fluoride reaction step (S101) is a step of mixing the iron-based slag with an ammonium fluoride compound. The ammonium fluoride reaction step (S101) is performed by mixing 50 to 500 parts by weight of the ammonium fluoride compound with 100 parts by weight of the steel slag.
In order to improve the reactivity, the iron-based slag is selected to have a particle size of 100 to 1,000 μm and used as a powder. When the grain size of the iron-based slag is less than 100 μm, there is no significant difference in the reaction rate, And the reaction rate is lowered when the grain size of the steel slag exceeds 1000 mu m.
The steel slag is mainly used in ironworks, etc. The slag generated in steelworks is mainly ferronickel slag, and the components contained in the ferronickel slag are shown in Table 1 below.
<Table 1>
As shown in Table 1, ferronickel slag, which is a steel slag generated in a steel mill or the like, contains a large amount of silicon oxide and magnesium oxide.
In addition, the ammonium fluoride compound is ammonium fluoride (NH 4 F), acidic ammonium fluoride (NH 4 HF 2) and silicon fluoride, ammonium {(NH 4) 2 SiF 6 )}, one fluoride ammonium phosphate {(NH4) 2 PO 3 F and Tetraalkylammonium fluoride. [0035] The term " fluorine-containing "
After mixing the above steel slag with the above ammonium fluoride compound, the reaction is carried out at a temperature of 80 to 200 ° C., and a ceramic ball for grinding is put into the reactor so that the metal fluoride produced by the reaction can maintain the powder state It is preferable to carry out the stirring process in one state.
At this time, ammonium fluoride and the fluoride of each metal component are produced through the ammonium fluoride reaction step (S101), and gaseous ammonia water is produced as a byproduct. From the amount of ammonia and water generated in the above reaction, And the generated ammonia water is collected using a condenser provided separately for use in the neutralization treatment of ammonium fluoride and magnesium fluoride (MgF 2), and the collected ammonia water can be diluted according to the use.
The reaction formula of the steel slag and the ammonium fluoride compound in the ammonium fluoride reaction step (S101) is shown in the following reaction formula 1
<Reaction Scheme 1>
Steel slag (Si, Mg, Ca, Fe ...) + xNH 4 HF 2 → (NH 4 ) 2 SiF 6 + MF + NH 3 + H 2 O
In addition, the ammonium fluoride reaction step (S101) will be described with reference to experimental examples.
<Experimental Example 1>
50 g of pulverized slag powder was put into a 1000 ml flask containing 200 g of ammonium bifluoride and 100 ml of water and stirred to prepare a mixture. At this time, a flask equipped with a stirrer, Dean Stark trap, a reflux condenser and a heating device was used, and stirring was carried out at a temperature of 110 ° C for 10 hours.
<Experimental Example 2>
Proceeding in the same manner as in Experimental Example 1, 150 g of ammonium fluoride was used.
<Experimental Example 3>
The procedure of Experimental Example 1 was repeated, except that 250 g of ammonium fluoride was used
<Experimental Example 4>
The procedure of Experimental Example 1 was repeated, except that 100 g of toluene was further mixed.
<Experimental Example 5>
Proceeding in the same manner as in Experimental Example 1, sodium boron trifluoride was used instead of ammonium fluoride.
The leaching rates of magnesium oxide and silica contained in the mixture prepared in Experimental Examples 1 to 5, the content of silicon oxide and solid matter (magnesium fluoride) contained in the filtrate after filtering the slurry, and the solids were measured, Respectively.
<Table 1>
In the solid-liquid separation step (S103), water is mixed with the mixture prepared through the ammonium fluoride reaction step (S101) and dissolved and filtered to perform solid-liquid separation. The mixture 100 500 to 2000 parts by weight of water is mixed with 100 parts by weight of the iron-based slag mixture to be fluorinated through the ammonium fluoride reaction step (S101). And after the dissolution, the solid ammonium fluoride filtrate and the solid metal fluoride solid are subjected to solid-liquid separation.
If the mixing amount of the water is less than 500 parts by weight, the solubility of the ammonium sulfide contained in the mixture is lowered. If the mixing amount of the water exceeds 2000 parts by weight, energy is consumed to dry the water in the silica collecting step, The efficiency of the recovery process may be lowered.
At this time, the solid-liquid separation process can be performed using various solid-liquid separators such as a pressure filter and a centrifugal separator. Magnesium is extracted from the solid material obtained in the solid-liquid separation step (S103) The silica is extracted from the liquid.
The step of recovering silica (S105) is a step of recovering silica by reacting ammonia water with the filtrate separated through the solid-liquid separation step (S103). In the solid-liquid separation step (S103) To recover the silica is shown in Scheme 1 below.
<Reaction Scheme 1>
(NH 4) 2 SiF 6 + 2NH 4 OH →
At this time, the ammonia water is preferably supplied gradually until the pH of the mixture finally reaches 8-10.
In the process of recovering silicon oxide through the above process, it is confirmed that the reaction proceeds completely through the pH of the filtrate upon the administration of ammonia. In the state where ammonia is remained, that is, in the basic state of 7 or more, 10 < / RTI >
The washing filtration step (S107) is a step of washing and filtering the recovered silica through the silica recovery step (S105). The water, ammonia water, and ammonium fluoride component remaining in the silica recovered through the silica recovery step (S105) The process proceeds to the step of removing the data.
More specifically, the water contained in the silica recovered by the filter press or the centrifugal filter is removed in order to remove the water contained in the recovered silica through the silica recovery step (S105), and the water- The process of adding the purified water to the reactor and mixing the purified water to reduce the concentration of the impurities contained in the water contained in the silica present in the cake state is repeated 2 or 3 times And lowering the concentration of the impurities contained in the silica.
Since the ammonium fluoride separated from the silica in the washing filtration step (S107) has a very high solubility in water of about 48%, water is removed and concentrated to a concentration suitable for use in the ammonium fluoride reaction step (S101) .
The solids purification step (S104) is the solid-liquid separation step to the step of purifying the separated solids through (S103), the solid-liquid separation step for industrial use for the separated solids through (S103) or silicon oxide (SiO 2) is removed, Washed with purified water three to five times, and dried.
Also, the solid purification step (S104) may be performed while increasing the pH of the solid by mixing an alkali solution containing sodium hydroxide, magnesium hydroxide, magnesium oxide, or the like into the solid material separated through the solid-liquid separation step (S103) When the pH of the mixture is 2 to 3, the iron component can be removed, and when the pH is 5 to 6, the impurities such as chromium and manganese can be removed.
The purity of the purified solid through the above process is improved, and the reactivity with ammonia water is improved in the magnesium hydroxide recovery step.
The magnesium hydroxide recovery step (S105-1) is a step of recovering magnesium hydroxide by reacting ammonia water with the purified solid matter through the solids purification step (S104). The solid matter purified through the solids purification step, as described above, The reaction of recovering magnesium hydroxide is shown in
<
MgF + NH 4 OH → Mg ( OH) 2 + (NH 4 F) 2
At this time, it is preferable to gradually supply the ammonia water until the pH of the mixture finally reaches 8 to 10. Since the recovery of magnesium hydroxide in the magnesium hydroxide recovery step (S105-1) must be carried out in a basic atmosphere , The ammonia water should be over-fed during the recovery process to maintain the pH at 8-10.
Since the ammonium fluoride generated in the above magnesium hydroxide recovery step (S105-1) has a very high solubility in water of about 48%, water is removed and concentrated to a concentration suitable for use in the ammonium fluoride reaction step (S101) It is preferable to reuse.
The firing step (S107-1) is a step of firing the recovered magnesium hydroxide through the magnesium hydroxide recovery step (S105-1). The magnesium hydroxide recovered through the magnesium hydroxide recovery step (S105-1) Followed by firing at a temperature of 700 to 2000 ° C.
In this firing step (S107-1), various kinds of magnesium oxide may be provided according to the firing temperature. When the firing step (S107-1) is performed at 700 to 1000 ° C, a light-burned magnesia is produced. Hard-burned magnesia is produced at 1000 to 1500 ° C, and dead-burned magnesia is produced at 1500 to 2000 ° C.
The baking furnace is not particularly limited and any baking furnace can be used, but it is preferable to use a baking furnace in a general form.
Therefore, the magnesium and silica recovery method using the steel slag according to the present invention is economical because the ammonium fluoride and ammonia water are circulated without any additional supply of acid or base components from the outside, In addition, it is possible to solve the problem of silica gel formation which occurs when silica is extracted as a solid by extracting the silica component into a liquid phase in solid-liquid separation.
S101; Ammonium fluoride reaction step
S103; Solid-liquid separation step
S105; Silica recovery step
S104; Solid Purification Step
S105-1; Magnesium hydroxide recovery step
S107; Washing filtration step
S107-1; Firing step
Claims (10)
A solid-liquid separation step in which water is mixed with the mixture prepared through the ammonium fluoride reaction step and dissolved and filtered to perform solid-liquid separation;
A silica recovery step of recovering silica by reacting ammonia water with the filtrate separated through the solid-liquid separation step;
A washing filtration step of washing and filtering the recovered silica through the silica recovery step;
A solid purification step of purifying the separated solid through the solid-liquid separation step;
A magnesium hydroxide recovery step of recovering magnesium hydroxide by reacting ammonia water with the purified solid through the solid purification step; And
And a calcining step of calcining the recovered magnesium hydroxide through the magnesium hydroxide recovery step,
In the solid-liquid separation step,
Wherein 500 to 2000 parts by weight of water are mixed with 100 parts by weight of the mixture prepared through the ammonium fluoride reaction step,
The ammonia water used in the silica recovery step and the magnesium hydroxide recovery step is generated in the ammonium fluoride reaction step,
In the magnesium hydroxide recovery step,
Wherein the amount of the ammonia water to be added is adjusted so that the pH of the reactant of the solid matter and the aqueous ammonia is adjusted to 8 to 10 so that the recovered magnesium hydroxide can be recovered in a basic state. Way.
Wherein the iron-based slag is pulverized and sorted to have a particle size of 100 to 1,000 mu m. The method for recovering magnesium oxide and silica using iron-based slag.
Wherein the ammonium fluoride compound is at least one selected from the group consisting of ammonium fluoride, ammonium fluoride, ammonium fluoride, ammonium fluorophosphate and tetraalkylammonium fluoride.
Wherein the ammonium fluoride reaction step is carried out by mixing 50 to 500 parts by weight of an ammonium fluoride compound with 100 parts by weight of a steel slag, and recovering the magnesium oxide and silica using the iron slag.
Wherein the ammonium fluoride compound generated in the silica recovery step and the magnesium hydroxide recovery step is reused in the ammonium fluoride reaction step after moisture is removed.
Wherein the calcining step is carried out at a temperature of 700 to 2000 ° C. 5. A method for recovering magnesium oxide and silica using a steel slag according to claim 1,
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| CN115679022B (en) * | 2021-07-23 | 2024-03-01 | 中国科学院过程工程研究所 | Steel slag stabilization treatment method |
| KR102567636B1 (en) * | 2022-08-17 | 2023-08-17 | 한국지질자원연구원 | METHOD FOR RECOVERING HIGH PURITY MgO FROM FERRONICKEL SLAG |
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