JPS5987043A - Tin oxide inorganic adsorbing material and preparation thereof - Google Patents

Abstract

PURPOSE:To obtain a homogenous and stable tin oxide adsorbing material high in adsorbing activity, excellent in cobalt adsorbing capacity and good in close adhesiveness, by a method wherein tin plating is applied onto a heat resistant and corrosion resistant carrier and a tin oxide thin layer is formed on the carrier by high temp. oxidation treatment. CONSTITUTION:As a heat resistant and corrosion resistant carrier, a particulate body, a fibrous body or a block body comprising a metal such as Ti or ceramics such as alumina is used and, after tin plating is applied to said carrier, the plated carrier is subjected to high temp. oxidation treatment at 800-1,000 deg.C to form a tin oxide thin layer on the carrier. This tin oxide is high in adsorbing activity while good in adhesiveness with the carrier due to solid phase reaction and a tin oxide inorg. adsorbing material excellent in practicality is obtained. Because this adsorbing material is high in adsorbing activity, excellent in Co adsorbing capacity and sufficient in function as a granulated body, it can be applied as the practical inorg. adsorbing material to a column for obtaining primary cooling water of a high temp. and high pressure nuclear reactor.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides an adsorption-active oxidation material suitable for use as an adsorption column material for removing high-temperature cobalt from reactor sub-coolant (hereinafter referred to as reactor water). This invention relates to an inorganic tin oxide adsorbent in which tin is supported on a carrier.

[Technical background of the invention and its problems]

Dissolved cobalt in reactor water, which is a cause of radiation exposure, is removed using the ion exchange resin method, but since ion exchange resin has a low heat resistance temperature (60°C or less), it cannot be used in high temperature, high pressure reactor water (280°C or less).
℃, 70KFI/cnF) has the disadvantage of not being used.

On the other hand, inorganic adsorbents have excellent heat resistance, and there are seven types of adsorbents that can be used under high temperature and high pressure reactor water conditions. For example, gold M=4 (iron, titanium, zirconium, manganese, niobium, tantalum, etc.) oxides, hydrated oxides, or metals (described above) and acid groups (phosphoric acid,
arsenic acid, tungstic acid, etc.), and metal oxides are particularly promising.

Inventor 5 has studied the cobalt adsorption capacity, reactor water stability, etc. of the gold F) oxide-based inorganic adsorbent, and as a result, L'
It was found that ¥8110 is the most practical.

Metal oxide-based inorganic adsorbents, including tin oxide, are generally in powder form and do not have mechanical strength on their own, so they cannot be applied as they are to a vat absorption column, and must be solidified by granulation. The following methods can be considered for solidifying the adsorbent.

(i) Directly solidify the adsorbent.

(2) Support on a suitable carrier.

In method (1), deterioration of cobalt adsorption activity due to solidification processes such as sintering and addition of binder is unavoidable and is difficult to use in practice.
There are many problems. Method (2) has a problem with the adhesion between the adsorbent and the carrier, but since there is a wide range of options regarding adsorption activity, it is estimated that the practical value is higher than method (1). Various attempts have been made to support inorganic adsorbents on carriers. For example, a carrier having pores is impregnated with an aqueous metal salt solution or a liquid metal-like compound, and then hydrolyzed and further (-
There is a method of supporting a metal oxide on a carrier by firing.

In this method, adsorption performance and adhesion are greatly affected by treatment conditions such as hydrolysis or calcination, making it difficult to control the conditions and making it difficult to obtain an adsorbent with homogeneous and stable performance.

[Purpose of the invention]

An object of the present invention is to provide an inorganic tin oxide adsorbent that has excellent adsorption activity, good adhesion, and is supported on a homogeneous and stable heat-resistant and corrosion-resistant carrier.

[Summary of the invention]

The tin oxide inorganic adsorbent according to the present invention is made by forming a thin layer of tin oxide on a heat-resistant and corrosion-resistant carrier, and the method for producing it is to use a heat-resistant and corrosion-resistant carrier, plate it with tin, and then apply high-temperature oxidation. The treatment produces a thin layer of tin oxide on the carrier.

In this way, tin oxide obtained by direct oxidation of metallic tin can be obtained by hydrolysis and calcination. It has higher adsorption activity than tin oxide, has good adhesion, and exhibits excellent cobalt adsorption ability.

[Embodiments of the invention]

Next, the present invention will be explained in detail by way of examples.

As the heat-resistant and corrosion-resistant L carrier, metal (titanium, etc.) is used.

zirconium, stainless steel, etc.) or ceramic (
Anotomina, titania, zirconia, etc.) granular bodies (spherical, cylindrical, hollow, crushed bodies, etc.).

Fibers, cones (whirl-shaped, linear, steel-shaped, etc.) or block bodies are applicable. In the example, it is made of hard alumina porcelain with an outer diameter of about 511 mψ, an inner diameter of about -13 mm, and a height of about 5 ynr.
A hollow cylindrical granular carrier of y was used.

First, a pretreatment is performed to enable the granular carrier to be plated with tin. As an example, palladium treatment is shown below.

・Tetraamine palladium chloride [Pd(NHs)+
) c127.5 g/It @ EDTA・2Na
8.0〃eAmmonia N■(40
H280//・Hydrazine (IM bath solution N2H48r
rJ/Isol solution/temperature 35
C. The granular carrier is placed in a cage and treated in a palladium treatment solution for 1 to 5 minutes while rotating and stirring the cage. Through this treatment, an extremely thin layer (approximately 0.01μ) of palladium is formed on the surface of the granular carrier.
is formed, allowing electroplating of the carrier.

After the pretreatment of the granular carrier, the intended tin plating treatment is performed. An example of tin plating on a carrier by the barrel method is shown below.

・Tin plating liquid composition Boron fluoride No. 19B Sm (BF4)2 2001
1/1 boric acid HBF4100~200 //Peptone 5 β-naphthol
1 g/A・Plating condition temperature 20~50°C current normal K
2~12 A/dm2πL pressure
1-3 ■Cathode The practical thickness of the tin plating on the pure tin plate granular carrier is approximately 0.1-10μ. In the example, tin plating with a redness of 3 μm was used.

The tin-plated granular carrier is subjected to a warm oxidation treatment that converts metallic tin into oxidized E (sno2), which serves as an adsorbent.

The high-temperature oxidation treatment involves heating the tin-plated carrier at a high temperature in air or oxygen atmosphere, and an example of the treatment is shown below.

・Temperature = 800-1000'C; ・Atmosphere: Pure oxygen (partial pressure 1 atm) Tin oxide produced on the surface of the carrier by this high temperature oxidation has high adsorption activity;
In addition, the inorganic adsorption of tin oxide, which has good adhesion to the hard alumina porcelain base and is highly practical, is obtained through the in-phase reaction.

The figure shows the cobalt adsorption ability of the tin oxide/#,r'ton adsorbent obtained in this example, the finely powdered tin oxide, and the powdered metal oxide adsorbent ((h). The result of this figure is expressed as follows.

Supported tin oxide Sr+02 collected from the tin oxide inorganic adsorbent obtained in this example + 5n of finely powdered tin oxide for comparison
02 (average particle size 003μ) and powdered magnetite as another adsorbent) FJ30. (average particle size 0.45μ),
Powdered titanium oxide TiO□ (average particle size 0.18 μ) and powdered large zirconium oxide 2,02 (average particle size 0.25 μ) were LOOPed into test water with cobalt ion concentrations of 120 P, P, and b, respectively. After adding the mixture to 3.00°C while stirring.

Cobalt ions were adsorbed with lh+, and the concentration of cobalt ions remaining in the test water was measured. As is clear from the figure, the supported SnO
It can be seen that No. 2 has better cobalt adsorption ability than fine powder SnO2 and other adsorbents.

〔Effect of the invention〕

As described above, the tin oxide inorganic adsorbent according to the present invention has high adsorption activity, excellent cobalt adsorption ability, and sufficient secondary performance as a granule, making it suitable for practical use in columns targeted for high-temperature and high-pressure reactor water. As an inorganic adsorbent, finely powdered tin oxide,
The graph shows the residual cobalt concentration in the test liquid after cobalt adsorption for each of powdered magnetite, powdered titanium oxide, and powdered i-fluconium oxide.

(7317> Agent Patent Attorney Noriyuki Chika (Idiot 1)
given name)

Claims (2)

[Claims] (1) An inorganic tin oxide adsorbent formed by forming a thin layer of tin oxide on a heat-resistant and corrosion-resistant carrier. (2) A method for producing an inorganic tin oxide adsorbent, in which a heat-resistant and corrosion-resistant carrier is used, the carrier is tin-plated, and then subjected to high-temperature oxidation treatment (secondary step to form a thin layer of tin oxide on the carrier).