KR0184254B1 - Gas phased cesium capturing material using waste fcc catalyst - Google Patents

Abstract

end. The technical field to which the claimed invention relates.

Collection phase of gaseous cesium using waste fluidized bed catalyst component solution (FCC) catalyst

I. The technical problem that the invention tries to solve

Conventionally, aluminum aluminosilicates have been used as a capturing material for gaseous cesium.

All. The point of the solution of the invention

The present invention relates to an FCC catalyst used in an oil refining company for decomposing heavy oil, which is a substance capable of replacing aluminum silicate by containing a large amount of silica and alumina components, and thus can be used as a capturing agent for gas phase cesium, And to provide a capture material for gaseous cesium which can enhance the added value of resources by recycling waste catalysts, relieve environmental pollution sources and ensure stable supply of cheap raw materials.

la. Important Uses of the Invention

Collecting material of gaseous cesium.

Description

Collection phase of gaseous cesium using waste fluidized bed catalyst component solution (FCC) catalyst

The present invention is intended to be used as a capturing agent for gas precursors (Cs) using a fluid catalytic cracking (hereinafter referred to as FCC) catalyst generated during a cracking process of a heavy oil in a petrochemical plant .

Aluminosilicates have been used as a capturing agent for conventional gaseous cesium. However, aluminum silicate has been replaced by a waste FCC catalyst to capture cesium which has a high risk of radioactive fission products and has a relatively good dissolution rate (Immobilization) material.

Aluminosilicates, which are currently attracting the most attention as cesium immobilization materials, include CsAlSiO ₄ , CsAlSi ₂ O ₆ and CsAlSi ₅ O ₁₂ as cesium aluminosilicates. Among these three compounds, pollucite (CsAlSi ₂ O ₆ ) is recommended as a most preferable cesium capturing material due to its magnetic field thermodynamic stability and high leaching resistance at disposal.

In addition, studies on the synthesis of cesium aluminosilicates have suggested the possibility of aluminum silicate as a filter raw material to effectively remove gaseous cesium, and cesium nitrate (CsNO ₃ ) and clay The feasibility of using these clay minerals as gaseous cesium capture materials by analyzing the reaction characteristics with metakaolin, bentonite and pyrophylite by thermogravimetry, differential thermal analysis and X-ray diffraction .

In order to prepare cesium aluminosilicates for capturing gaseous cesium, a proper Si / Al molar ratio of the aluminum silicate clay minerals and a careful heat treatment are required, and kaolin having a Si / Al molar ratio of 1 (CsAlSiO ₄ ) and pyrophillite (Si / Al molar ratio = 2) were found to be the most thermodynamically stable and highly pollutant pollucite formed at the disposal. When the Si / Al molar ratio is greater than 2, the larger the Si / Al molar ratio, the higher the volatilization amount of cesium at higher temperatures. This indicates that the Si / Al mole ratio of the aluminum silicate clay mineral is very important in collecting cesium compounds.

Meanwhile, unlike conventional petrochemical catalysts, the waste FCC catalyst generated during the decomposition process of heavy oil from oil refineries is not a catalyst of metal in the carrier but is used for decomposing heavy oil using zeolite. That is, since vanadium, nickel, and the like accumulate and diffuse on the surface of the zeolite due to the decomposition of heavy oil during the heavy oil cracking process and the catalyst function is lowered, the material is discarded and is currently used only in a limited place for producing cement raw materials, ceramics and bricks. The inventors of the present invention have found that the above-mentioned waste FCC catalyst is mainly composed of zeolite, Si / Al = 2.2, and the porosity and porosity of the catalyst are relatively large, so that aluminum silicate capable of producing cesium- It is possible to recycle the FCC spent catalyst as a capturing material for gaseous cesium, thereby recycling it as a resource material recycle material and a high value-added functional material.

As such, the object of the present invention is to provide an FCC catalyst which can be substituted for aluminum silicate by containing a large amount of silica and alumina components and being used as a capturing agent for gaseous cesium, To improve the productivity and workability, to increase the added value of resources by recycling spent catalyst, and to ensure the stable supply of low-cost raw materials by eliminating environmental pollution sources.

Hereinafter, the present invention will be described in detail with reference to Examples.

As shown in Table 1, the components of the FCC spent catalyst are chemical components, which are composed of 60 to 70% of silicon dioxide (SiO ₂ ), 25 to 32% of aluminum oxide (Al ₂ O ₃ ) , The proportion of particles of 10 탆 or less is 31.6%, that of 60-80 탆 or less is 66.3%, the proportion of particles of 80-95 탆 or less is 83% or less, the content of nickel is 0.1-0.4%, the content of nickel is 0.1-0.4% 95% or less for 95-110 μm or less, and 100% or less for 110-130 μm or less. Also, the BET surface area (m 2 / g) is 138 and the ABD (g / ml) is 0.856.

Thus, since the pulsed FCC catalyst is an aluminum silicate raw material containing a large amount of silica and alumina components, the pulverized FCC catalyst is suitable as a trap material for the gas particulate in the fission products in terms of chemical composition and physical properties, Or the pulverized powder may be used as a cesium capturing material after the metallic powder is oxidized at 500 to 1000 占 폚. Hereinafter, the present invention will be described in detail with reference to examples.

[Example 1]

Cesium nitrate (CsNO) or cadmium iodide (CsNO) as a source of waste FCC catalyst and gaseous cesium as the capturing material of gaseous cesium for the purpose of producing pollucite, which is known as the most stable compound of cesium aluminosilicates (Hereinafter referred to as " TGA "), differential thermal analysis (hereinafter referred to as DTA) and X-ray diffractometry (XRD) ) And the possibility of its application as a cesium sorbent by analysis of reaction products.

The reaction characteristics of cadmium iodide (CsI) with cesium nitrate (CsNO) were investigated in the pulverized and unfractured state of the pulsed FCC catalyst produced in the cracking process.

The spent FCC catalyst of the present invention contains not less than 87% by weight of alumina and silica components as shown in Table 1, and has a Si / Al molar ratio of about 2.2.

The Si / Al molar ratio of the aluminum silicate clay minerals reported is very important for the formation of pollucite (CsAlSiO), which is known as the most stable compound among the cesium-aluminum silicates. The Si / Al molar ratio of the FCC spent catalyst is very close to the ideal value 2.0 have.

X-ray diffraction analysis of the coal fly ash used in the experiment showed that the closed FCC catalyst consists of zeolite and SiO (quartz). I could. Waste FCC catalysts form typical spherical particles with sufficient silica and alumina.

The results of DTA and TGA analysis of cesium nitrate (CsNO) mixture of fly ash in an air atmosphere show that the endothermic peak at 409 ℃ has a broad endothermic peak at 613 ℃ and 820 ℃. The endothermic peak at 409 ° C is due to the melting of cesium nitrate (CsNO) and is in good agreement with the results. The endothermic peak between 613 ° C and 820 ° C is interpreted to be due to the decomposition reaction of cesium nitrate (CsNO). When the temperature was raised above 820 ° C, no change was observed on the DTA curve or the TGA curve, indicating that a very stable compound was formed.

X-ray diffraction analysis of the reaction products obtained by heating the mixture of waste FCC catalyst and cesium nitrate (CsNO) to 1000 ℃ showed that zeolite and SiO (quartz) peaks, which are the constituents of coal fly ash, disappear and pollucite peaks And it was confirmed that it was generated.

On the other hand, the pollucite formation reaction of aluminum silicate and cesium nitrate (CsNO) can be expressed as (1) 2CsNO = CsO + NO and (2) CsO + AlO · 4SiO = CsO · AlO · 4SiO, the total weight loss of 13.9% of the sample was 13.6% by weight of NO generated by the decomposition of cesium nitrate (CsNO), and the weight of CsO volatilized And the weight loss is 0.3%. Therefore, the ratio of cesium nitrate (CsNO) to the reaction is estimated to be 99.2%.

Waste FCC catalyst and pollutant cucumber nitrate (CsNO) reaction product, observed 500 times magnification by scanning electron microscope, have a rough surface and a bulky crystal form and show a very different shape from spherical waste FCC catalyst.

[Example 2]

DTA and TGA analysis of the mixture of waste FCC catalyst and cadmium iodide (CsI) in the air atmosphere revealed that the narrow endothermic peak at 638 ° C has a broader endothermic peak at 650 ° C to 940 ° C . The endothermic peak at 638 ° C corresponds to the melting point of cesium iodide (CsI). And the endothermic peak at 650 ℃ to 940 ℃ is interpreted as a result of the decomposition reaction of cesium iodide (CsI). It can be seen that even when the temperature is raised above 940 ° C, no change is observed on the DTA curve or the TGA curve, indicating that a very stable compound is formed. On the other hand, the X-ray diffraction analysis of the reaction product produced by heating the mixture of the waste FCC catalyst and the cesium iodide (CsI) to 1000 ° C. showed that the zeolite and SiO 2 (quartz) peaks constituting the pulsed FCC catalyst disappear and the pollucite peak It can be seen that it was created.

On the other hand, since the iodine sate (CsI) is decomposed into CsO and I in an oxidizing atmosphere, the reaction of producing aluminum chloride (aluminosilicate) and cesium iodide (CsI) in a high temperature air atmosphere is 3CsI + ½O = CsO + I and (4) CsO + AlO + 4SiO = CsO · AlO · 4SiO. When the pollucite formation reaction occurs, the total weight loss of the material is 39.3%, which is the decomposition reaction of cesium iodide The difference in the weight loss due to the emission of I was 27.4% and the sum of the weight loss by volatilization of CsO not participating in the reaction and 13.6% Therefore, the proportion of CsI participating in the reaction is estimated to be about 55.2%.

The polluted FCC catalyst and pollucite, which is a reaction product of cesium iodide (CsI) observed by scanning electron microscope 500 times magnification, are rough and bulky crystals which are very different from spherical pulsed FCC catalysts, It is similar to pollucite produced from a mixture of waste FCC catalyst and cesium nitrate (CsNO).

As a result of the analysis of the cesium capture reaction characteristics by using DTA, TGA, XRD, SEM, etc. using waste FCC catalyst, which is a waste of decomposition process of petroleum chemical heavy oil, the mixture of waste FCC catalyst and cesium nitrate (CsNO) , And a mixture of waste FCC catalyst and cesium iodide (CsI) was found to be thermally stable at 940 ° C or above, forming a rough, bulky round crystalline form of pollucite.

Therefore, it can be confirmed that the waste FCC catalyst having a silica / alumina content of 87% or more and a Si / Al molar ratio of about 2.2 is a suitable material capable of collecting gaseous cesium in the form of pollucite at a high temperature.

As described above, it is very important to recycle the waste FCC catalyst, which has been used for low-cost cement, building materials, or partly discarded, as a capturing material for cesium (Cs) (Cs) as a capturing agent for cesium (Cs). However, since zeolite and the like are considerably expensive, it can be used as a low-cost waste FCC catalyst to produce cesium (Cs) The cost can be greatly reduced, and it is a very useful invention that never lags in the physical and chemical properties of conventional cesium (Cs) trap materials.

Claims (3)

(SiO ₂ ) 60 to 70% aluminum oxide (Al ₂ O ₃ ) 25 to 30%, iron (Fe) 0.1 to 0.5%, nickel (Ni Wherein the waste FCC catalyst having a composition of 0.1 to 0.4% of Na, 0.1 to 0.4% of sodium and 0.1 to 0.4% of vanadium (V) is pulverized and used as a cesium capturing material. Catalytic Casing of Gas Phase Cesium. The method according to claim 1, wherein the waste FCC catalyst is pulverized, and the powder is used as a cesium capturing material by oxidizing metallic powder at 500 to 1000 占 폚. Collecting material of cesium. Use of a waste fluidized bed catalytic component solution (FCC) catalyst as claimed in any one of claims 1 to 3, characterized in that it comprises a waste FCC catalyst having a particle size of 110 mu m and an average density of 40 to 80 mu m, Collecting material of cesium.