RU2251169C1 - Method for recovering toxic and radioactive material neutralization wastes - Google Patents

Abstract

FIELD: recovery of biologically hazardous wastes.

SUBSTANCE: proposed method includes introduction of toxic and radioactive material neutralization wastes into reactor together with charge, heating them with aid of superhigh-frequency energy, and hardening; toxic material neutralization wastes are decomposed in the course of heating. Reactor charge composed of river sand and cullet doped with boron acid and red lead in 5 : 1 proportion is used for hardening wastes by vitrification.

EFFECT: enhanced quality of waste recovery.

1 cl, 1 dwg, 1 tbl

Description

Currently, there is the problem of the destruction of waste resulting from the detoxification of chemical warfare agents (BWA) and waste generated during the operation of nuclear reactors.

In the first case, these are reaction masses (RM), which retain small amounts of starting materials at the level of 10 ^-4 %. In the adopted technology, PM is treated with calcium salts, poured with bitumen, molded and stored in such sealed form in special airtight storages with limited access to them. The procedure is energy-intensive, expensive and, most importantly, not having the prospect of using the resulting mass (see. Methods for destroying organophosphorus poisonous substances. Russian Chemical Chem. 1993, v. 37, No. 3, p. 27).

In the second case, spent rods with a certain radiation level are accumulated in storage tanks with a high degree of protection, ensuring their safe storage. During long-term storage, depressurization of storage facilities cannot be ruled out (see Komarov V.I. et al. Processing of radioactive waste using microwave energy. Electronic equipment. Ser. Microwave technology, issue 2 (476), 2000, p.30- 36).

A known method of exposure to microwave energy (BHF) energy on BWA with the purpose of their decomposition and detoxification (see Patent No. 2093229, Russia. The method of thermal decomposition of toxic substances. Elder Ya.A., Kochergin A.I., publ. 20.10.97, , bull. "Inventions, utility models" No. 29). The method allows to reduce the toxicity of BWA by 4-5 orders of magnitude, but does not solve the problem of solid residues that accumulate and need further processing.

Closest to the proposed method is a method of processing liquid and solid radioactive waste, organophosphorus toxic substances and pesticides (see Patent No. 2176417, Russia. Method for the processing of highly toxic industrial waste. Lyashenko A.V., published on November 27, 2001). Highly toxic industrial waste is mixed with a mineral binder containing calcium cement and metallurgical waste. The resulting mixture is filled into the reactor container and heated with microwave energy to 200 ° C. After isothermal exposure of the mixture at a fixing temperature, the resulting polycrystalline cement matrix is cooled. This method provides long-term and reliable immobilization of industrial waste.

The disadvantages of the prototype are the following: 1). Low process temperature at which residues of the organic component are possible. 2) Storage of the obtained polycrystalline matrices is not unlimited and requires supervision.

A method for processing waste neutralization of toxic substances and radioactive waste, including their placement in the reactor along with the charge, heating using microwave energy and curing. The difference of the proposed method lies in the fact that when heated, decomposition of toxic neutralization waste is carried out, and for the solidification of the waste by vitrification, a mixture containing river sand and glass cullet with the addition of boric acid and lead minium is used in a ratio of 5: 1.

Reactors for the reaction mass of toxic substances can be structurally different. However, the operating mode is almost the same, because associated with physical processes that occur in substances under the influence of microwave oscillations. When exposed to radiation at a frequency of 2450 MHz due to the absorbing properties of substances, intense heating occurs to 1000-1100С °. If a composition is exposed to this effect, which includes, in addition to the waste of ecotoxicants, components of the glass charge, the whole mass vitrifies. For example, the dry residue after detoxification of V _x gas has the composition: Na-29%, P-2.7%, C-0.7%, Cl-41%, F-0.6%, Si-5%, O- 21% The components of the glass mixture are added to this composition in the ratio: river sand - 30-35%, boric acid - 15-20%, lead minium - 3-4%, waste - 30-35%, cullet - the rest.

The table shows the experimental data on the vitrification of the mixture using microwave energy, using a 5.0 kW magnetron.

The drawing shows a diagram of the installation on which the experiment was conducted. The installation consists of a magnetron 1, a circulator with a sealing section 2, an air fan 3, screw adjustment knobs 4, a waveguide 5, a chimney 6, a thermocouple at the entrance to the waveguide 7, a reactor 8, a thermocouple at the outer wall of the reactor 9, a microammeter 10, a milliammeter 11 The diagram does not indicate the magnetron power source. A mixture was poured into reactor 8. After the magnetron 1 was turned on, the glass melt was heated. The power is adjusted by a milliammeter 11 in the anode circuit of the magnetron. The reflected power is determined by the readings of the microammeter 10 in the reflected power circuit of the circulator 2.

The table shows the experimental data on the readings. Obviously, an increase in power leads to an increase in speed and a reduction in the heating time of the charge. The actual temperature of the charge could be judged indirectly by the incandescent color of the reactor flange. Color - raspberry, which corresponds to 800-850 ° C. The temperature of the charge was much higher, because the mixture was melted, which indicates the beginning of vitrification, which occurs at a temperature of 1000-1100 ° C.

As a result of vitrification, the volume of the product will be 3-4 times less than in the accepted chemical technology of detoxification of BWA, and the requirements for its storage will be significantly reduced. The resulting glass mass during the destruction of the reaction masses from the detoxification of chemical warfare agents is suitable for further use, for example, in the production of glass for technical purposes.

These factors should provide significant economic benefits over technology adopted.

Claims (1)

A method of processing waste neutralization of toxic substances and radioactive waste, including their placement in the reactor with the charge, heating using microwave energy and curing, characterized in that during heating decomposition of waste neutralization of toxic substances, and for the solidification of waste by vitrification using a charge containing river sand and cullet, with the addition of boric acid and lead minium in a ratio of 5: 1.