KR102325084B1 - Composition for neutralizing acidic waste water or harmful gas having low freezing point - Google Patents

Abstract

The present invention relates to a composition for neutralizing acidic wastewater or acidic harmful gas with a lowered freezing point, and the composition of the present invention is easy to treat in a neutralization process even at a low temperature and is effective in neutralizing acidic harmful gases, and sodium hydroxide, calcium Since there is a neutralization treatment effect similar to using each of the compounds, it can be very usefully used in the industrial field related to the treatment of acidic wastewater or acidic harmful gas.

Description

Composition for neutralizing acidic waste water or harmful gas having low freezing point

The present invention relates to a composition for neutralizing acidic wastewater or acidic harmful gas having a lowered freezing point.

Acidic wastewater refers to wastewater containing a large amount and high concentration of inorganic waste acid discharged from petroleum refining plants and organic synthesis plants. inhibit activity. If there is a lot of sulfide in sewage, hydrogen sulfide gas is generated, and if cyanide is contained, there is a risk of generating cyan gas, which is dangerous. If the wastewater is sulfuric acid, it should be neutralized and precipitated with an alkali agent, and if it is an organic acid, it should be discharged after neutralization and biological treatment.

As a method of treating acidic wastewater, there is a method of adding an alkali neutralizing agent such as caustic soda (NaOH), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), and slaked lime (Ca(OH) _{2 ).} The method of adding an alkali neutralizer is a method of precipitating and separating heavy metals contained in acidic wastewater into hydroxide form. However, in this method, the pH control range is different depending on the alkali neutralizer, and the pH range to be removed for each heavy metal is different, so it is impossible to remove some heavy metals depending on the type of neutralizing agent. And, even if possible, it is a reality that a large amount of industrial waste that causes secondary environmental pollution is generated by using an inexpensive neutralizing agent for economic reasons.

For example, when the acidity of wastewater is strong at pH 3 or less and large-capacity, it is most preferable to use caustic soda that can be neutralized to pH 14 as a neutralizing agent to convert heavy metals into hydroxides for precipitation separation. However, if the price of caustic soda is higher than other alkali neutralizers and the content of caustic soda exceeds 5%, it is classified as a toxic substance under the Chemicals Control Act, making it difficult for related companies to bear and manage it. can It is therefore common to use limestone or quicklime or slaked lime to neutralize acidic wastewater. However, in this case, there is a problem of causing secondary environmental pollution due to the large amount of waste generated after neutralization, that is, sludge.

Recently, the burden and management of related companies such as storage facilities, user facilities, and users of hazardous chemicals is becoming more difficult due to the strengthening of regulations on the Chemicals Control Act. In particular, the cost of landfill waste is rising rapidly due to its capacity limit. Therefore, there is a need to develop a neutralizing agent product that is classified as a non-hazardous chemical substance while maintaining the performance and effect of an alkali agent used in the prior art, so that it is easy to manage and supervise.

Meanwhile, Korean Patent No. 0587667 discloses a 'toxic gas purifier', and Korean Patent No. 0562048 discloses a 'method for producing basic copper carbonate from acidic copper chloride waste solution'. However, the 'composition for neutralizing acidic wastewater or acidic harmful gas with a lowered freezing point' of the present invention has not yet been disclosed.

The present invention has been derived from the above needs, and the present inventors have developed sodium hydroxide, potassium hydroxide, aluminum hydroxide, sodium carbonate, calcium A mixed alkali agent containing a mixture of a compound and an alcohol was prepared, and the mixed alkali agent does not form sludge even at low temperatures, so it is easy to treat the neutralization process in winter as well as sodium hydroxide and calcium compounds used in the existing neutralization process. By confirming that there is a neutralization treatment effect similar to that, the present invention was completed.

In order to solve the above problems, the present invention provides a composition for neutralizing acidic wastewater or acidic harmful gas containing a mixture of sodium hydroxide, potassium hydroxide, aluminum hydroxide, sodium carbonate, calcium compound and alcohol as an active ingredient.

In addition, the present invention provides a method for neutralizing acidic wastewater or acidic noxious gas, comprising the step of treating the neutralizing composition to acidic wastewater or acidic noxious gas.

The mixed alkali agent of the present invention is easy to neutralize even at low temperatures and is effective in neutralizing acidic harmful gases, and has a neutralization treatment effect similar to that of using each of the conventional sodium hydroxide and calcium compounds, so that acidic wastewater or acid hazardous It can be very usefully used in gas processing related industries.

1 is a result of comparing the input amount of a mixed alkali agent containing a mixture of sodium hydroxide, potassium hydroxide, aluminum hydroxide, sodium carbonate, calcium compound and alcohol of the present invention when neutralizing 10% hydrochloric acid and the input amount by sodium hydroxide (caustic soda) concentration .
Figure 2 is a result of confirming the freezing point (freezing point) of the mixed alkali agent comprising a mixture of sodium hydroxide, potassium hydroxide, aluminum hydroxide, sodium carbonate, calcium compound and alcohol of the present invention.

In order to achieve the object of the present invention, the present invention provides a composition for neutralizing acidic wastewater or acidic harmful gas containing a mixture of sodium hydroxide, potassium hydroxide, aluminum hydroxide, sodium carbonate, calcium compound and alcohol as active ingredients.

The acidic wastewater is, for example, sulfuric acid method titanium dioxide manufacturing plant wastewater, plating wastewater, electronics industry wastewater, battery manufacturing plant wastewater, steel mill pickling wastewater, acid waste generated during acid production, lead acid from metal smelting plants, zinc waste acid It means wastewater with high acidity of pH 2 to 3, etc.

Since the composition for neutralization of the present invention maintains a liquid state without forming sludge even at -5°C, existing products (mixed alkali agent including sodium hydroxide, sodium carbonate and calcium hydroxide) form sludge at low temperature (4°C). The neutralization process can solve the problem of poor treatment efficiency, and the neutralization composition of the present invention is a mixture of sodium hydroxide, potassium hydroxide, aluminum hydroxide, sodium carbonate, calcium compound and alcohol, and the amount of sodium hydroxide treated as a poison is 5% or less It reduces the amount of calcium hydroxide, which generates a lot of landfill waste, to 5% or less, and relatively increases the amount of sodium carbonate to produce a mixture. indicates Therefore, the composition for neutralization of the present invention can increase the treatment efficiency of the neutralization process even at low temperatures, and the price competitiveness is lowered due to the use of sodium hydroxide alone, and it is classified as a toxic substance (more than 5% of sodium hydroxide) according to the Chemicals Control Act. It has the advantage of being able to solve the difficult problem and also reduce the amount of landfill waste by reducing the amount of calcium hydroxide.

In the composition for neutralizing acidic wastewater or acidic harmful gas of the present invention, the mixture comprises 1 to 4.9% by weight of sodium hydroxide, 1 to 4.9% by weight of potassium hydroxide, and 1 to 4.9% by weight of aluminum hydroxide, based on the total weight of the composition. It may include, but is not limited to, sodium carbonate of 7% by weight, calcium compound of 1-5% by weight, and alcohol of 1-10% by weight. The composition of the present invention includes water as the remainder, and water may include 73 to 85% by weight.

In addition, the calcium compound may be any one selected from the group consisting of slaked lime, calcium carbonate and quicklime, preferably slaked lime, but is not limited thereto. The alcohol may be any one selected from the group consisting of methanol, ethanol, propanol, isopropanol and butanol, preferably methanol, but is not limited thereto.

In addition, the acidic harmful gas may be at least one selected from the group consisting of sulfurous acid gas, hydrogen chloride gas, chlorine gas, hydrogen fluoride gas, boron trichloride gas, aluminum chloride gas, titanium tetrachloride gas and nitrogen dioxide gas, but is not limited thereto.

In addition to the mixture, the composition for neutralization of the present invention may further include calcium chloride or magnesium chloride, but is not limited thereto. The calcium chloride or magnesium chloride is used to prevent pipe scale (scale), it is preferably included in each less than 1% by weight based on the total weight of the composition.

The composition for neutralizing acidic wastewater or acidic harmful gas of the present invention comprising calcium chloride or magnesium chloride is 1 to 4.9% by weight of sodium hydroxide, 1 to 4.9% by weight of potassium hydroxide, and 1 to 4.9% by weight of hydroxide based on the total weight of the composition Aluminum, 1 to 7% by weight of sodium carbonate, 1 to 5% by weight of a calcium compound, 0.1 to 1% by weight of calcium or magnesium chloride, 1 to 10% by weight of alcohol and 73 to 85% by weight of water However, it is not limited thereto.

In addition, the present invention provides a method for neutralizing acidic wastewater or acidic noxious gas, comprising the step of treating the neutralizing composition to acidic wastewater or acidic noxious gas.

Hereinafter, an embodiment of the present invention will be described in detail. However, the following examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples.

Example 1. Neutralizing effect of mixed alkali agent of the present invention

In the present invention, after preparing a mixed alkali agent (Table 1) containing a mixture of sodium hydroxide (caustic soda), potassium hydroxide, aluminum hydroxide, sodium carbonate, calcium hydroxide (slaked lime) and methanol, neutralizing 10% hydrochloric acid (based on 100 ml) A single input amount for each sodium hydroxide concentration used for this purpose was compared with the input amount of the mixed alkali agent of the present invention. As a result, as shown in FIG. 1, the neutralizing effect was obtained at the input amount (31.3 g) of the 17 to 18% caustic soda treatment concentration alone and the input amount of the mixed alkali agent of the present invention (32.1 g: 1.5 g of which is caustic soda). something similar could be found. Through this, it is thought that it can be usefully utilized as a mixed alkali agent in which the neutralizing effect is maintained while reducing the amount of sodium hydroxide treated as a toxic substance.

Mixed alkali agent composition of the present invention ingredient weight% sodium hydroxide 4.5 potassium hydroxide 4.5 aluminum hydroxide 2 sodium carbonate 6 Calcium hydroxide (slaked lime) 2 Calcium Chloride or Magnesium Chloride 0.7 methanol 5 water 75.3 gun 100

In addition, the neutralization effect of using the mixed alkali agent of the present invention and calcium hydroxide (slaked lime 20%) alone was compared for 1,000 ml of acidic wastewater. As a result, as shown in Table 2 below, when the mixed alkali agent of the present invention was used to neutralize 1,000 ml of acidic wastewater, the amount of sludge was reduced by about 81% and the remaining amount of fluorine (F) was 1.2% increased, and it was confirmed that this neutralizing effect was similar to the neutralizing effect when calcium hydroxide (slaked lime) was used alone. Through this, the mixed alkali agent of the present invention reduces the amount of calcium hydroxide (20% → 1-5%) that increases the amount of landfill waste, and the neutralizing effect is maintained similar to that of the conventional neutralizer, so it is usefully used as a neutralizing agent for treating acidic wastewater, etc. It is presumed that it could be

Neutralizing effect of mixed alkali agent when neutralizing acidic wastewater Test 1 Test 2 Test 3 Remarks (device, comparison) Slaked Lime (20%) input 10.8 11.1 10.9 amount of sludge 13.9 14.1 14.1 KETT-FD610 F remaining 26 29 27 HACH DR1900 mixed alkali agent input 14.2 14.4 14.3 amount of sludge 2.65 2.71 2.7 KETT-FD610 F remaining 26 29 28 HACH DR1900 Raw water pH (pH) 2.57 2.58 2.57 Mettler Toledo S220 Acidity after neutralization (pH) 7.4 7.5 7.5 Mettler Toledo S220 Stirring time (min) 30 30 30 Raw water F (fluorine) content (ppm) 316 316 316 HACH DR1900 Sludge Volume Comparison ^* 19.1% 19.2% 19.1% Average decrease of about 80.9%
(compared to slaked lime) F Remaining comparison ^* 100.0% 100.0 103.7% Average increase of about 1.2%
(compared to slaked lime)

Furthermore, as a result of confirming the freezing point of the alkali agent of the mixture of sodium hydroxide, potassium hydroxide, aluminum hydroxide, sodium carbonate, calcium compound and alcohol of the present invention, it did not form sludge even at -5.3° C. and maintained a liquid state, -8.3 It was confirmed that the sludge form was shown at ℃ (Fig. 2). Therefore, through the composition of the present invention, existing own products (composition of a mixture of sodium hydroxide, sodium carbonate and calcium hydroxide) become sludge at a low temperature (4°C), thereby solving the problem that the neutralization process treatment efficiency decreases in winter.

Claims (6)

4.5% by weight of sodium hydroxide based on the total weight of the composition; 4.5% by weight of potassium hydroxide; 2% by weight of aluminum hydroxide; 6% by weight of sodium carbonate; 2% by weight of slaked lime; 5% by weight of methanol; 0.7% by weight of calcium chloride or magnesium chloride; and 75.3% by weight of water as an active ingredient, maintaining a liquid state at -5°C, and producing 18 to 19% of sludge relative to the input amount of the composition. delete delete delete delete A method for neutralizing acidic wastewater comprising the step of treating the acidic wastewater with the composition for neutralization of claim 1 .

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