JPS61293546A - Acidic gas removing agent - Google Patents

Abstract

PURPOSE:To obtain the titled removing agent which is excellent in water resistance and strength and shows the high absorption and adsorption performance for an acidic gas by blending colloidal silica as a binder to zeolite, bentonite and slaked lime and molding the mixture. CONSTITUTION:An aimed purifying agent is obtained by blending colloidal silica to (a) zeolite being crystalline alumina silicate, (b) bentonite having montmorillonite as an essential component and (c) slaked lime, granulating, molding and drying the mixture. The aimed purifying agent obtained by such a way shows the extremely high effective absorption and adsorption performance for an acidic gas such as gaseous hydrogen chloride, gaseous nitric acid and gaseous hydrogen fluoride and also is excellent in water resistance and large in the strength of single grain and easy in the handling and available industrially.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an acidic gas removing agent, and more particularly to an acidic gas removing agent that is excellent in water resistance, strength, and acidic gas removal rate.

<Conventional technology> Typical air pollutants include sulfur dioxide gas,
Acidic gases such as hydrogen chloride gas, hydrogen fluoride gas, and nitric acid gas exist, but the typical methods known in the past include removing them by using the adsorption effect of activated carbon, or by absorbing and removing them with an alkaline agent. ing.

<Problems to be solved by the invention> However, activated carbon [HC1, HFXHNOs, etc.] has a low adsorption capacity for acidic gases, and there are saturation phenomena and desorption phenomena of adsorption to activated carbon, and extremely dilute There were problems such as low adsorption capacity for concentrated gases.

Means for Solving the Problems〉 As a result of repeated research to solve the above problems, the inventor has found that
The present invention has been obtained.

That is, the present invention is an acidic gas removing agent formed by blending colloidal silica as a binder with zeolite, bentonite, and slaked lime and molding the mixture.

The zeolite applicable to the present invention is a crystalline aluminosilicate having a so-called zeolite crystal structure and whose cations can be exchanged.

This crystal structure is easily confirmed by X-ray diffraction, making the substantially amorphous aluminosilicate unsuitable as a bulk material.

Examples of this type of zeolite include A-type, X-type, and Y-type zeolites.
and P-type zeolites, mordenite, analsite, sodalite group aluminosilicates, clinoptilolite, erionite, chabasite, etc., and these may be either synthetic or natural products, and There is no need to particularly limit the manufacturing method for synthetic products.

Next, bentonite is a well-known clay mineral whose main components are montmorillonite, which mainly contains 5iOz and Al2O3 and has a 5i02/A1zOs ratio of about 4.4 to 77.

Further, as the slaked lime, either a reagent or an industrial product can be used, but one with a fine viscosity is preferred because it has good reactivity with colloidal silica. For example, industrial slaked lime code (, Tl
5R9001), etc. Note that slaked lime also includes quicklime, which is a precursor that can be used as water due to the presence of water during molding.

In addition, the colloidal silica that is blended as a binder with these three components is a silica sol with an average particle diameter of 30 m.
5 to 50 weight as 8102 silica component less than μ,
Usually 10 to 30% by weight is colloidally dispersed in water.

The composition of the acidic gas removing agent according to the present invention can be varied depending on the purpose of use and the type of pollutant gas, but in most cases, zeolite is 10 to 2 [wt4],
It is made by blending 1 to 20 wt4 of bentonite as 10 and molding it.

The reason for this is that outside the above composition range, the gas removal effect,
This is because it is difficult to obtain a cylinder quality product that is suitable for use as an acidic gas remover, such as moldability and water resistance of molded products.

For example, if bentonite is less than 10wt4, it has low plasticity and lacks moldability, whereas if it exceeds 30wt4, the pore volume of the molded product tends to decrease, degrading the performance. 'Wt4 and below,
Even if other ingredients are changed, the performance is inferior. This is probably due to the adsorption power of zeolite itself and the function of zeolite water.

Furthermore, if the slaked lime is less than 50wt4, its life as a gas removal agent will be short, and if it is more than 80wt4, the pore volume will be small and the reaction rate with acidic gas will tend to decrease. Outside the range, the quality is poor.

The acidic gas removing agent according to the present invention is prepared by blending the above-mentioned components in predetermined amounts, adding water if necessary, thoroughly mixing and kneading, and then
It is a molded product that is granulated using a granulator. After granulation, it can be used as is, but in most cases it is heated at 50 to 150C.
It is preferable to dry at a temperature of .

In addition, the shape of the above granules may be spherical, cylindrical, acicular, lumpy,
There is no particular restriction, as it may be in the form of gravel or the like.

Although it is molded, the granules do not collapse even when used at high temperatures and are water resistant enough to withstand long-term use, but this is probably due to slaked lime, amorphous or crystalline calcium silicate. This is thought to be due to the fact that the adsorption capacity is improved and the binding effect is exerted.

<Example> Example 1 Zeolite: 10 fi parts Bentonite: 20 Slaked lime = 70 Colloidal silica: 7 (Contains 8102304) After adding 52 parts by weight of water to each component in the above blending ratio, mixing and kneading, extrusion molding machine The granules were granulated to a size of 6 mm and dried to obtain 100 parts by weight of an acidic gas removing agent.

(Acidic gas removal test) A predetermined amount of the removal agent obtained in Example 1 is packed into a packed column, the acidic gas to be removed is passed through at a constant flow rate, and the acidic gas concentration at the inlet and outlet of the column is measured. Table 1 shows the results of determining the removal rate.

Table 1 (Water resistance test) Approximately 11 of the remover obtained in Example 1 was placed in a 1001 Nessler tube, 1001 Lt of water was added thereto, and the liquid was moved occasionally.
- Although it was left for several months, no collapse was observed.

Effect> The acidic gas removal agent according to the present invention exhibits highly effective absorption and adsorption performance against acidic gases such as hydrogen chloride gas, hydrogen fluoride gas, and nitric acid gas, and has excellent water resistance. Moreover, it is industrially useful because it does not generate dust, is easy to handle, and has a high single-grain strength.

Claims (1)

[Claims] (1) An acidic gas remover made by blending zeolite, bentonite, and slaked lime with colloidal silica as a binder and molding the mixture.