KR102116688B1 - Composition for desulfurizing and stabilizing heavy metals - Google Patents

Abstract

The present invention is sodium bicarbonate 90 to 96% by weight; And 4 to 10% by weight of a heavy metal dissolution inhibitor; and 2 to 5% by weight of dolomite; 1 to 3% by weight of iron sulfate; And it provides a composition for inhibiting desulfurization and dissolution of heavy metals, characterized in that consisting of 1 to 5% by weight of an alkali additive. The composition for inhibiting desulfurization and heavy metal dissolution according to the present invention is excellent in removing acidic gases generated in the sintering process and suppressing heavy metal dissolution during desulfurization dust, and wastes produced after desulfurization process meet environmental standards to reduce waste treatment costs. It can be reduced and has the effect of solving problems caused by heavy metals when recycling waste.

Description

Composition for inhibiting desulfurization and dissolution of heavy metals {Composition for desulfurizing and stabilizing heavy metals}

The present invention relates to a composition for inhibiting desulfurization and heavy metal dissolution, and more particularly, to a composition for inhibiting desulfurization and heavy metal dissolution, which is excellent in removing acid gas generated in a sintering process and inhibiting heavy metal dissolution in desulfurization dust.

Sintering means to make the powder into a solid binder by heating the powder below the melting point or to a degree of partial melting, and the sintering process of the steel mill uses the blended raw materials including spectroscopy, limestone, powder coke, semi-gloss and powdered coal in the sintering machine. It is a process to produce sintered ore for combustion and charging to the blast furnace. In the sintering process of the steel mill, since the exhaust gas contains a large amount of sulfur (S), sulfur is removed from the exhaust gas by using a desulfurization facility to prevent air pollution. In this process, the waste generated by treating sulfur oxides contains heavy metals, so it is eluted from water quality or soil during landfill, causing serious environmental pollution.

Particularly, since the iron sintering process uses iron ore, various minerals, and raw materials such as coal, a large amount of fine dust containing acid gas and heavy metals is generated in the combustion process, and the fine dust has a high lead (Pb) content, resulting in a dissolution test. In the case of exceeding the legal standard of 3ppm, it is impossible to landfill general waste, so it is landfilled with specific waste.

In order to solve this problem, calcium hydroxide (Ca (OH) ₂ ) or sodium bicarbonate (NaHCO ₃ ) was conventionally used as a desulfurizing agent. However, calcium hydroxide does not cause the problem of elution of heavy metals, but has a problem of low desulfurization efficiency due to low reactivity, and sodium bicarbonate has the advantage of having a high desulfurization efficiency, but there is a problem that heavy metals are eluted. Accordingly, in recent years, a number of studies have been conducted on compositions capable of suppressing elution of heavy metals.

Republic of Korea Patent No. 10-1573002 relates to "a composition for removing sulfur oxides from sintered flue gas and a method for removing sulfur oxides from sintered flue gas", sodium hydrogen carbonate 84 to 95% by weight; Heavy metal stabilizer 01 to 3% by weight; And 1 to 5% by weight of a neutralizing agent; the heavy metal stabilizer is a xanthate-based compound, and the composition has a content of each component so that the sum of the total components is 100% by weight. Disclosed is a composition for removing sulfur oxides from a sintered exhaust gas that is selected. However, the composition for removing sulfur oxides according to the Republic of Korea Patent No. 10-1573002 has a problem that the removal effect of lead or a compound in the heavy metal is not superior to the amount of the heavy metal stabilizer.

In addition, Republic of Korea Patent No. 10-0935204 relates to "a solid body containing a solidifying agent having a function of inhibiting the dissolution of heavy metals and a method for manufacturing the solidifying agent, 10 to 17 wt% of solidifying agent, 20 to 30 wt% of designated waste containing heavy metals" , The solidifying aid of fly ash or bituminous coal is composed of 4 ~ 8wt%, 25 ~ 51wt% of general wastes of mineral or waste casting, cement 15 ~ 20wt%, wherein the solidifying agent has a spherical particle size (size) 25mm, density ( Density) 342, Absorption 05% to 615wt% of quenched steel slag with 05%, particle size 05 to 80㎛, specific gravity 312 to 320, Portland cement 30 to 50wt% with specific surface area 2,800㎠ / g, alum and calcium carbonate Inhibition of heavy metal elution, characterized in that it is composed of a mixture of 8 ~ 12wt% of the expansion agent formed by mixing, specific gravity (20 ℃) 1690, water insoluble amount (Water insoluble amount) 02% water glass 05 ~ 5wt% A solid body containing a functional solidifying agent is disclosed. However, the solidifying agent according to the Republic of Korea Patent No. 10-0935204 has a problem that it is difficult to configure to have the effect of inhibiting desulfurization and heavy metals at the same time, and the manufacturing process of the solid body is difficult and expensive.

An object of the present invention is to provide a composition for inhibiting desulfurization and heavy metal dissolution, which is excellent in the removal of acid gas generated in the sintering process and the suppression of heavy metal dissolution in desulfurization dust.

Another object of the present invention is to provide a composition for inhibiting desulfurization and dissolution of heavy metals, which can reduce waste treatment costs by complying with environmental standards.

Another object of the present invention is to provide a composition for inhibiting desulfurization and dissolution of heavy metals that can solve problems caused by heavy metals when recycling waste.

The above and other objects of the present invention can be achieved by the present invention described below.

Desulfurization and heavy metal dissolution inhibiting composition according to an embodiment of the present invention, sodium bicarbonate 90 to 96% by weight; And 4 to 10% by weight of a heavy metal dissolution inhibitor; and 2 to 5% by weight of dolomite; 1 to 3% by weight of iron sulfate; And 1 to 5% by weight of an alkali additive.

Here, the dolomite is characterized by having a particle diameter of 50 to 100㎛.

The alkali additive is characterized in that it is calcium hydroxide (Ca (OH) ₂ ) or sodium hydroxide (NaOH).

The present invention has an excellent function of removing acid gas generated in the sintering process and suppressing heavy metal elution during desulfurization dust, and wastes produced by desulfurization process can reduce waste treatment costs by meeting environmental standards and when recycling wastes. It has the effect of the invention to provide a composition for inhibiting desulfurization and dissolution of heavy metals that can solve problems caused by heavy metals.

The above-described objects, features and advantages of the present invention will become more apparent by explaining preferred embodiments and comparative examples of the present invention in detail. The following detailed description is not to be described in a limiting sense, and the scope of the present invention is limited only by the appended claims, along with all ranges equivalent to those claimed.

Desulfurization and heavy metal dissolution inhibiting composition according to the present invention, sodium bicarbonate 90 to 96% by weight; And 4 to 10% by weight of a heavy metal dissolution inhibitor; and 2 to 5% by weight of dolomite; 1 to 3% by weight of iron sulfate; And 1 to 5% by weight of an alkali additive.

Sodium bicarbonate (NaHCO ₃ ) is a substance having a white monoclinic crystal that is produced as an intermediate during the production of sodium carbonate. When heated, carbon dioxide (CO ₂ ) and water (H ₂ O) are generated, resulting in sodium carbonate (Na ₂ CO ₃ ). It is converted, and the sodium carbonate (Na ₂ CO ₃ ) has excellent desulfurization performance in combination with substances that cause environmental pollution such as sulfuric acid gas, chlorine gas, and fluoride gas in the exhaust gas. Sodium bicarbonate is preferably composed of 90 to 96% by weight relative to the total weight of the composition for inhibiting desulfurization and dissolution of heavy metals according to the present invention. If the compounding amount is less than 90% by weight, desulfurization performance is lowered, and when the compounding amount is more than 96% by weight, the heavy metal dissolution suppression performance is lowered.

The heavy metal dissolution inhibitor is a material added to sodium bicarbonate, which is a main component of the desulfurization agent, and is preferably composed of 4 to 10% by weight based on the total weight of the composition for inhibiting desulfurization and heavy metal dissolution according to the present invention. In addition, the heavy metal dissolution inhibitor may include 2 to 5% by weight of dolomite; Iron sulfate 1.5 to 3% by weight; And 0.5 to 2% by weight of an alkali additive.

Dolomite (CaMg (CO ₃ ) ₂ ) is a trigonal mineral formed by dolomite formation of calcite. In addition, it is preferable to use dolomite having a particle diameter of 50 to 100 μm because dolomite has excellent adsorption performance to heavy metals when it has a particle diameter of 50 to 100 μm. With regard to the dolomite heavy metal adsorption mechanism, dolomite undergoes a decomposition reaction represented by CaMg (CO ₃ ) ₂ → MgO + CaCO ₃ + CO ₂ by firing, and has a pore surface through the firing, during the desulfurization process. Absorbs acid gas and heavy metals. Calcium carbonate produced through the calcination process of dolomite undergoes a desulfurization process in the reaction formula of CaCO ₃ + SO ₃ → CaSO ₄ + CO ₂ and reacts with acid gas to turn into gypsum, and gypsum adsorbs heavy metals. In the reaction formula of FeSO ₄ H ₂ O + M (OH) ₂ → Fe (OH) ₃ + MSO ₄ , ferrous sulfate undergoes a desulfurization process and reacts with hydroxides of M (alkali and alkaline earth metals) to change to iron hydroxide and iron hydroxide is Adsorb heavy metals. Here, MgO serves as a catalyst for promoting the reaction of calcium carbonate and ferrous sulfate, and reacts with acid gas to form stable sulfur oxides. Heavy metals show higher adsorption and aggregation at high alkalinity. In an environment with low alkalinity, the adsorbed heavy metal may be eluted again.

As the alkali additive, calcium hydroxide (Ca (OH) ₂ ) or sodium hydroxide (NaOH) can be preferably used. Alkali additives have the property of reacting with acidic gases, but their efficiency is low, so most of the added amount serves to increase the alkalinity of the desulfurization dust. Since the heavy metal dissolution inhibitor exhibits a reaction of simultaneously adsorbing acid gas and heavy metal, it is possible to prevent the desulfurization efficiency from being reduced due to a decrease in the amount of sodium bicarbonate.

Hereinafter, the present invention will be described in more detail by using Examples and Comparative Examples of the present invention. However, the following examples correspond to preferred embodiments of the present invention, and the present invention is not limited to the following examples.

One. Example

Example  One

90 g of sodium bicarbonate, 5 g of dolomite, 3 g of ferrous sulfate and 2 g of calcium hydroxide were added to a weightless mixer to mix for 5 minutes, and then the composition was compressed to prepare a composition for suppressing desulfurization and elution of heavy metals.

Example  2

It was performed in the same manner as in Example 1, except that 90 g of sodium bicarbonate, 3 g of dolomite, 2 g of ferrous sulfate, and 5 g of calcium hydroxide were added to a weightless mixer.

Example  3

It was performed in the same manner as in Example 1, except that 94 g of sodium bicarbonate, 3 g of dolomite, 2 g of ferrous sulfate, and 1 g of calcium hydroxide were added to a weightless mixer.

Example  4

It was carried out in the same manner as in Example 1, except that 94 g of sodium bicarbonate, 4 g of dolomite, 1 g of ferrous sulfate and 1 g of calcium hydroxide were added to a weightless mixer.

Example  5

It was carried out in the same manner as in Example 1, except that 96 g of sodium bicarbonate, 2 g of dolomite, 1.5 g of ferrous sulfate and 1.5 g of calcium hydroxide were added to a weightless mixer.

Example  6

It was carried out in the same manner as in Example 1, except that 96 g of sodium bicarbonate, 2 g of dolomite, 1 g of ferrous sulfate and 1 g of calcium hydroxide were added to a weightless mixer.

2. Comparative example

Comparative example  One

94 g of sodium bicarbonate, 4.2 g of dolomite, 0 g of ferrous sulfate and 1.8 g of calcium hydroxide were added to a weightless mixer to mix for 5 minutes, and then the composition was compressed to prepare a composition for suppressing desulfurization and elution of heavy metals.

Comparative example  2

It was performed in the same manner as in Comparative Example 1, except that 94 g of sodium bicarbonate and 6 g of dolomite were added to a weightless mixer.

Comparative example  3

It was performed in the same manner as in Comparative Example 1, except that 94 g of sodium bicarbonate, 1 g of dolomite, 4 g of ferrous sulfate, and 1 g of calcium hydroxide were added to a weightless mixer.

3. Heavy metal dissolution test

Using the compositions of Examples 1 to 6 and Comparative Examples 1 to 3, 200 g of each sample of desulfurization dust generated in the sintering process and hydrochloric acid in purified water were added to pH 6.0 for a solvent: sample (solvent (1:10 ( W: V) is mixed in a 2,000 ml Erlenmeyer flask to prepare a sample solution, and the prepared sample solution is shaken at room temperature and normal pressure for 200 shakes per minute and a 5 cm amplitude shaker is used for 6 hours in a row. After shaking, it was filtered through a glass fiber filter of 1.0 µm, and an appropriate amount of the filtrate was taken to prepare a test solution for elution test, after which the elution amount of heavy metals of chromium (Cr), copper (Cu), cadmium (Cd) and lead (Pb) Was measured according to the waste process test method.

The component ratios and heavy metal dissolution tests of Examples and Comparative Examples are summarized in the following table.

Table 1

Table 2

When the composition for suppressing desulfurization and elution of heavy metals was not used for desulfurization equipment in the desulfurization dust generated during the sintering process, the measured heavy metal content was chromium (Cr) 0.47 mg / ℓ; Copper (Cu) 12.72 mg / l; Cadmium (Cd) 0.58 mg / L; And lead (Pb) 27.03 mg / L. On the other hand, in Comparative Examples 1 to 3, which do not fall within the preferred range of the present invention, the removal effect of chromium (Cr), cadmium (Cd), copper (Cu) and lead (Pb) was recognized to some extent, but met the acceptance criteria. If not, or meet the acceptance criteria, heavy metals in the range that could cause environmental pollution were eluted.

 However, as can be seen in Tables 1 and 2, when the compositions of Examples 1 to 6 according to the preferred range of the present invention were used, chromium (Cr) and cadmium (Cd) were not detected, and copper (Cu) Was not detected or was detected in an extremely small amount, and lead (Pb) was detected in a very small amount, and it was confirmed that the effect of suppressing elution of heavy metals was very excellent.

Therefore, the composition for inhibiting desulfurization and heavy metal dissolution according to the preferred embodiment of the present invention has excellent desulfurization function and is very excellent in suppressing various heavy metal dissolution, thus removing acid gas generated in the sintering process and heavy metal in desulfurization dust Industrial use is possible as a composition for suppressing elution.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments described above. That is, a person having ordinary knowledge in the technical field to which the present invention pertains can make a number of changes and modifications to the present invention without departing from the spirit and scope of the appended claims, and all such appropriate changes and modifications Equivalents should also be considered within the scope of the present invention.

Claims (3)

Sodium bicarbonate 90% by weight; And
10% by weight of heavy metal elution inhibitor;
The heavy metal elution inhibitor is 5% by weight of dolomite; Iron sulfate 3% by weight; And calcium hydroxide (Ca (OH) ₂ ) 2% by weight,
The dolomite is a composition for inhibiting desulfurization and elution of heavy metals, characterized in that it has a particle diameter of 50 to 100㎛. delete delete