SU711092A1 - Method of producing cadmium sulfate based thermoluminophore - Google Patents

Description

The invention relates to a method for producing a thermolaminated phosphor based on cadmium sulfate, intended for use in X-ray image converters for inspection of materials and products.

A known method for producing a thermoluminophore based on a bivalent metal sulphate, in particular, calcium, by dissolving calcium sulphate and activator salts in hot sulfuric acid, followed by crystallization of the phosphor during the evaporation of sulfuric acid l.

This method is not applicable to the production of cadmium sulfate-based thermolaminates, since the latter is insoluble in sulfuric acid.

A known method for producing a thermoluminophore based on cadmium sulfate, including the preparation of a wet mixture containing sulphate, cadmium and activator salts, by displacing cadmium sulfate with water, a solution of activator salts and melting, drying the mixture at 120 ° C

for 10 hours and its thermal operation at 10 ° C 2.

The disadvantage of this method is the gas sensitivity of the thermolaminated material obtained to the x-ray radiation, and therefore converters based on it can be used in X-ray inspection, only to control products of low density.

The aim of the invention is to develop a method for producing x-nil {ophor with higher sensitivity to x-rays.

Claims (2)

This is achieved by the fact that, in the method of producing a thermionic acid, which involves the preparation of a wet batch, the preserved cadmium sulfate and the combination of activators, the drying of heat 1, its heat treatment, the wet mixture is blended by mixing the sulfonic acid with the activator compound, followed by processing the mixture with the rest of the perfume, and the perfume. Protecting is carried out at 85-11 ° C in a test. US-SHO h.ch. then at 290-330-C until complete removal of the black acid, and heat treatment is carried out at 580-63 ° C. Before drying, it is desirable to hold the wet mixture at room temperature for 15-20 hours. In the proposed method, powdered cadmium sulfide reacts with sulfuric acid to form cadmium sulfate and hydrogen sulfide. The reaction proceeds with the release of a large amount of heat, under the action of which the formation of hydrogen sulfide occurs with the simultaneous decomposition of sulfuric acid into oxides SgOj, 2 SO, 304. Therefore, for the most complete course of the reaction, sulfuric acid is birch; in excess with respect to cadmium sulfide. In addition, sulfur is present in the mixture, since these oxides can be reduced by hydrogen sulfide by the reaction: SOa ЗН2О + 4S The charge of the mixture is desirable for more complete homogenization of the mixture and crystallization of the base of Cu SO 4 - First drying of the mixture at 85-110 C for a long time is necessary to achieve a maximum defect concentration due to the presence of sulfur in the mixture, the intensive formation of which occurs during the decomposition of sulfur oxide. This explains the lower limit of the temperature range. The upper limit of it is limited by the melting point of sulfur. The second drying is carried out to remove excess sulfuric acid and is carried out at a temperature close to or equal to its boiling point. A tertiary treatment of the charge of conductor 1 at a temperature of 580-630 ° C is optimal for this method. The criticality of the limits of the heat treatment mode is due to the sharp dependence of the light sum output on the processing temperature. Example. 27 mg Mgl OF-H2O and 36.5 mg SmCtjj are dissolved in 5% acid and mixed with 10 g cadmium sulfide. The resulting mixture was dried at 12 ° C for 4 hours and treated with 11.5 ml of concentration sulfuric acid. The wet broth is kept for 15 hours at room temperature, dried at 85 ° C for 150 hours, then at 290 ° C for 3 hours. Dry mixture prik; poured at 580 ° C for 3 hours. EXAMPLE 2 A wet mixture containing cadmium sulphates and activators is prepared as in Example 1, held at room temperature for 20 hours, dried at HO C for 100 hours, then at 330 ° C for 2 hours and calcined at 63 ° C for 1 hour. The drawing shows the thermoluminescence curves of thermolumines produced by the known (curve 1) and proposed (curve 2) methods. It is shown that the thermoluminophores obtained by the proposed method have a sensitivity of 5 times Bbuue than the thermoluminophores obtained in a known manner, which allows them to be used for inspection of objects up to 2 mm thick. Claim 1. Method for producing cadmium sulfate-based thermolaminate, including preparing a wet mine containing cadmium sulfate and activator compounds, drying the mixture and its thermal treatment, characterized in that, in order to increase the sensitivity of the thermoluminophor to X-rays, the wet mixture is prepared by mixing cadmium sulfide with activator compounds, followed by treating the mixture with concentrated sulfuric acid, drying the mixture at 85–110 ° C for 1OO– 150 h, then at 290 -330 ° C until complete removal of sulfuric acid, and heat treatment is carried out at 58 ° -630 ° C. 2 The method according to claim 1, that is, so that before drying the wet mixture is kept for 15-2O hour at room temperature temperature Sources of information taken into account in the examination 1. USSR Patent No. 372825, cl. GOl T 1/11, published. 10.03.73. 2. The patent of England 1347672, cl. With 4 S, pub. 20.O2.74 (prototype). 15t, HUH