阅读说明：本技术 一种稀土冶炼放射性废渣处理方法 (Rare earth smelting radioactive waste residue treatment method ) 是由 蔡兰花 王芳 李培则 于 2020-05-17 设计创作，主要内容包括：本发明涉及环保领域,具体关于一种稀土冶炼放射性废渣处理方法；包括：粉碎,拌浆,洗选,浮选和沉淀脱水；本发明提供了一种用分选的方法将稀土冶炼放射性废渣中的主要放射性物质选出的处理方法,本发明不同于现有技术采用添加其他物质,改变其配合比以降低其放射性,而是利用放射性物质比重较高这一特性,采用分选的方法将放射性物质从废渣中提取出来,达到降低废渣的放射性的目的；本发明公布使用的一种浮选抑制剂,能够加速放射性物质的分离,提高分离效率,进一步降低废渣中的放射性；本方法能够大量处理稀土冶炼放射性废渣,能够减少放射性废弃物质的总量,方便处理,达到保护环境的目的,具有较高的实际应用价值和经济价值。(The invention relates to the field of environmental protection, in particular to a method for treating radioactive waste residues in rare earth smelting; the method comprises the following steps: crushing, slurry mixing, washing, flotation and precipitation dehydration; the invention provides a processing method for selecting main radioactive substances in rare earth smelting radioactive waste residues by using a sorting method, which is different from the prior art that other substances are added and the mixing proportion is changed to reduce the radioactivity of the radioactive substances, but the radioactive substances are extracted from the waste residues by using the characteristic that the specific gravity of the radioactive substances is higher, so that the aim of reducing the radioactivity of the waste residues is fulfilled; the invention discloses a flotation inhibitor which can accelerate the separation of radioactive substances, improve the separation efficiency and further reduce the radioactivity in waste residues; the method can treat a large amount of rare earth smelting radioactive waste residues, can reduce the total amount of radioactive waste substances, is convenient to treat, achieves the aim of protecting the environment, and has higher practical application value and economic value.)

1. A rare earth smelting radioactive waste residue treatment method mainly adopts the scheme that:

step one, crushing, namely adding 800 parts of rare earth smelting radioactive waste residues of 500-800 parts into a crusher for crushing, then sieving in a sieving device, wherein the diameter of a sieve mesh is 0.2-0.7mm, and returning the sieved coarse particles to the crusher for re-crushing;

step two, stirring slurry, namely uniformly stirring the crushed rare earth smelting radioactive waste residues and 800 parts of 300-800 parts of water in a stirring and mixing kettle according to the parts by mass to form 18-26% of radioactive waste residue slurry with high fluidity;

washing, namely adding washing water into the uniformly stirred radioactive waste residue slurry in a washing system for washing, wherein the proportion of the radioactive waste residue slurry is high, the radioactive waste residue is precipitated under the action of the washing water, waste residues with high radioactive substance content are separated, the water amount of the washing water is 40-100L/min, and the radioactive waste residues washed out with the water enter a flotation system;

step four, flotation, namely adding a foaming agent, an activating agent and a flotation inhibitor into a flotation system, wherein the addition amount of the foaming agent, the activating agent and the flotation inhibitor is 700g/t, 50-200g/t and 300g/t of radioactive waste per ton, after the addition of the agents is finished, foaming is carried out in the flotation system, the radioactive waste is settled at the bottom, the specific gravity of the primary product is high, and other waste floats to the upper layer along with the foam under the action of the foaming agent and the flotation inhibitor, so that the upper layer substances are filtered;

and step five, precipitation and dehydration, namely precipitating the floated upper-layer substances, and dehydrating and filtering to obtain the treated rare earth smelting waste residue.

2. The method for treating the radioactive waste residues generated in the rare earth smelting according to claim 1, which is characterized by comprising the following steps: the preparation method of the flotation inhibitor comprises the following steps:

adding 12.3-18.2 parts of maleic acid, 6.8-10.5 parts of mercaptopropylsilane and 60-100 parts of ethanethiol into a reaction kettle according to the mass parts, stirring for 10-40min, uniformly mixing, adding 0.5-2.1 parts of 10-15% chloroplatinic acid n-butyl alcohol solution, stirring for 30-60min, heating to 70-90 ℃, stirring for reaction for 60-120min, then adding 4.3-8.6 parts of diallyl trisulfide, stirring for reaction for 20-40min at 70-90 ℃, cooling to subzero 5-subzero 15 ℃, then adding 2.1-5.7 parts of urea, stirring for reaction for 10-30min, filtering, and evaporating the solvent in the filtrate to dryness to obtain the flotation inhibitor.

3. The method for treating the radioactive waste residues generated in the rare earth smelting according to claim 1, which is characterized by comprising the following steps: and step one, the screening equipment is a vibrating screen.

4. The method for treating the radioactive waste residues generated in the rare earth smelting according to claim 1, which is characterized by comprising the following steps: and the foaming agent in the fourth step is pine oil or eucalyptus oil or camphor oil.

5. The method for treating the radioactive waste residues generated in the rare earth smelting according to claim 1, which is characterized by comprising the following steps: and the activating agent in the fourth step is sodium sulfide.

6. The method for treating the radioactive waste residues generated in the rare earth smelting according to claim 1, which is characterized by comprising the following steps: and step four, the foaming mode in the flotation system is mechanical stirring type foaming or inflatable type foaming or pressure dissolved air type foaming.

7. The method for treating the radioactive waste residues generated in the rare earth smelting according to claim 1, which is characterized by comprising the following steps: and step four, combining the waste residues obtained from the bottom layer waste residues and the waste residues with higher radioactive substance content obtained from the step three, and performing centralized treatment.

Technical Field

The invention relates to the field of environmental protection, in particular to a method for treating radioactive waste residues in rare earth smelting. .

Background

China is a large rare earth country, the smelting amount of the rare earth industry is huge, but rare earth raw ore and concentrate used for processing and smelting contain radioactive substances higher than the natural background, so a large amount of radioactive waste residues are generated in rare earth smelting.

CN1277165A discloses radioactive cement containing rare earth waste residues, which is prepared by uniformly cold mixing 60-84 wt% of cement and 16-40 wt% of 100-200 mesh rare earth waste residues. The sewage treating process includes adding proper amount of sandstone, water reducing agent, early strength agent, compacting agent and water into radioactive cement in 20-60 wt%, mixing to form cement member, settling pond, water pipe, etc. and storing or flowing sewage for 2-4 hr. The cement of the invention has small radiation dose and no harm to human body without protection. The method can reduce COD in the sewage by 20-50% in only 2-4 hours, the degradation rate of coliform bacteria is more than 99%, the field radiation is safe and meets the national standard, and the indexes of total alpha value, beta value and the like of the treated water are lower than the indexes specified by the national standard.

CN108342598A discloses a method for separating associated radionuclides in rare earth waste residue leachate, which specifically comprises the steps of performing solid-liquid separation after the rare earth waste residue is subjected to acid leaching, wherein the liquid phase contains the associated radionuclides, Ce and the like, and performing co-precipitation separation of the associated radionuclides by using urea-formaldehyde resin after the Ce is extracted by an organic phase; the organic phase and the urea-formaldehyde resin are separated again, so that the organic phase and the urea-formaldehyde resin can be recycled, closed cycle is realized, the cost is saved, and secondary pollution and radioactive waste transfer are avoided.

CN111020196A discloses a method for separating thorium and enriching rare earth from radioactive waste residue leachate based on POAA, which comprises the following steps: (1) performing liquid-liquid extraction on the leachate of the radioactive waste residue and a POAA solution to obtain an organic phase loaded with thorium ions and an extracted water phase, and performing back extraction on the organic phase loaded with the thorium ions by using an acid solution to obtain a regenerated POAA solution and a thorium ion enriched solution; (2) extracting the raffinate water phase in the step (1) with saponified POAA to obtain a rare earth precipitate and raffinate, and pickling the rare earth precipitate to obtain regenerated POAA and rare earth ion enrichment liquid; in the method, unsaponified POAA has better selectivity on thorium, rare earth is not extracted from unsaponified POAA basically, the extraction efficiency of thorium can reach more than 99% by optimizing the extraction conditions, and the rare earth enriched by POAA precipitation after saponification has the advantages of high settling speed, large size of precipitated particles, small environmental influence and recyclability.

The above patents and the prior art mostly use the method of adding other substances, changing the mixing ratio of the substances to reduce the radioactivity of the substances, and meeting the regulations of national standards, and the method has high cost and strong limitation.

Disclosure of Invention

In order to solve the problems, the invention provides a method for treating radioactive waste residues in rare earth smelting.

A rare earth smelting radioactive waste residue treatment method mainly adopts the scheme that:

step one, crushing, namely adding 800 parts of rare earth smelting radioactive waste residues of 500-800 parts into a crusher for crushing, then sieving in a sieving device, wherein the diameter of a sieve mesh is 0.2-0.7mm, and returning the sieved coarse particles to the crusher for re-crushing;

step two, stirring slurry, namely uniformly stirring the crushed rare earth smelting radioactive waste residues and 800 parts of 300-800 parts of water in a stirring and mixing kettle according to the parts by mass to form 18-26% of radioactive waste residue slurry with high fluidity;

washing, namely adding washing water into the uniformly stirred radioactive waste residue slurry in a washing system for washing, wherein the proportion of the radioactive waste residue slurry is high, the radioactive waste residue is precipitated under the action of the washing water, waste residues with high radioactive substance content are separated, the water amount of the washing water is 40-100L/min, and the radioactive waste residues washed out with the water enter a flotation system;

step four, flotation, namely adding a foaming agent, an activating agent and a flotation inhibitor into a flotation system, wherein the addition amount of the foaming agent, the activating agent and the flotation inhibitor is 700g/t, 50-200g/t and 300g/t of radioactive waste per ton, after the addition of the agents is finished, foaming is carried out in the flotation system, the radioactive waste is settled at the bottom, the specific gravity of the primary product is high, and other waste floats to the upper layer along with the foam under the action of the foaming agent and the flotation inhibitor, so that the upper layer substances are filtered;

and step five, precipitation and dehydration, namely precipitating the floated upper-layer substances, and dehydrating and filtering to obtain the treated rare earth smelting waste residue.

A method for treating radioactive waste slag from rare earth smelting uses mercaptopropyl silane as raw material.

A rare earth smelting radioactive waste residue treatment method adopts maleic acid as a raw material.

A rare earth smelting radioactive waste residue treatment method adopts diallyl trisulfide as a raw material.

The preparation method of the flotation inhibitor comprises the following steps:

adding 12.3-18.2 parts of maleic acid, 6.8-10.5 parts of mercaptopropylsilane and 60-100 parts of ethanethiol into a reaction kettle according to the mass parts, stirring for 10-40min, uniformly mixing, adding 0.5-2.1 parts of 10-15% chloroplatinic acid n-butyl alcohol solution, stirring for 30-60min, heating to 70-90 ℃, stirring for reaction for 60-120min, then adding 4.3-8.6 parts of diallyl trisulfide, stirring for reaction for 20-40min at 70-90 ℃, cooling to subzero 5-subzero 15 ℃, then adding 2.1-5.7 parts of urea, stirring for reaction for 10-30min, filtering, and evaporating the solvent in the filtrate to dryness to obtain the flotation inhibitor.

The mercapto propyl silane, the maleic acid and the diallyl trisulfide have hydrosilylation reaction, and part of the reaction is as follows:

and step one, the screening equipment is a vibrating screen.

And the foaming agent in the fourth step is pine oil or eucalyptus oil or camphor oil.

And the activating agent in the fourth step is sodium sulfide.

And step four, the foaming mode in the flotation system is mechanical stirring type foaming or inflatable type foaming or pressure dissolved air type foaming.

And step four, combining the waste residues obtained from the bottom layer waste residues and the waste residues with higher radioactive substance content obtained from the step three, and performing centralized treatment.

The invention relates to a method for processing radioactive waste residues in rare earth smelting, which provides a method for sorting out main radioactive substances in the radioactive waste residues in the rare earth smelting, and is different from the prior art that other substances are added, the mixing proportion is changed to reduce the radioactivity of the radioactive waste residues, but the radioactive substances are extracted from the waste residues by using the characteristic of higher specific gravity of the radioactive substances, so that the aim of reducing the radioactivity of the waste residues is fulfilled;

the invention discloses a flotation inhibitor, wherein the mercaptopropyl silane, maleic acid and diallyl trisulfide have hydrosilylation reaction, and simultaneously contain-SH and trisulfide, so that the separation of radioactive substances can be accelerated, the separation efficiency is improved, and the radioactivity in waste residues is further reduced; the method can treat a large amount of rare earth smelting radioactive waste residues, can reduce the total amount of radioactive waste substances, is convenient to treat, achieves the aim of protecting the environment, and has higher practical application value and economic value.

Drawings

Figure 1 is a fourier infrared spectrum of the flotation depressant product prepared in example 2.

At 1772cm^-1The absorption peak of the carboxyl group is determined to be 1451cm^-1The in-plane bend absorption peak of carbon and oxygen having carboxyl groups in the vicinity thereof was 927cm^-1The out-of-plane bend absorption peak of oxygen and hydrogen with carboxyl nearby is 2909cm^-1A telescopic absorption peak of the hydrocarbon exists nearby, which indicates that the maleic acid participates in the reaction; at 2545cm^-1The nearby area has a telescopic absorption peak of hydrogen sulfide at 723cm^-1A stretching absorption peak of silicon carbon exists nearby, which indicates that the mercaptopropyl silane participates in the reaction; at 764cm^-1A carbon-sulfur telescopic absorption peak exists nearby, which indicates that diallyl trisulfide participates in the reaction.

At 1641cm^-1No obvious absorption peak of carbon-carbon double bond nearby, which shows that the carbon-carbon double bond of maleic acid and diallyl trisulfide has reacted, and 2147cm simultaneously^-1And no strong hydrosilation peak exists nearby, which indicates that the hydrosilation bond of the mercaptopropyl silane is broken, and the hydrosilation addition reaction is carried out on the hydrosilation bond and the carbon-carbon double bond of the carbon-carbon double bond to produce the silicon-carbon bond, and simultaneously the carbon-carbon double bond of the maleic acid and the diallyl trisulfide is consumed, so that a product with a target structure is generated.

Detailed Description

The invention is further illustrated by the following specific examples:

the radioactivity of the sample is detected by a gamma dose rate instrument in the experiment, and the dose rate measurement range of the instrument is as follows: 10nGy/-100mGy/h, useThe energy range is: 50keV-3 MeV; the radioactivity standard of the sample refers to the radioactivity requirement in the standard specification of GB 6566-. Radionuclide limit I of rare earth smelting radioactive waste residue treated by the method_RaA value of 2.31 and a specific activity of C_thThe value was 21.547 Bq/kg.