CN109903875A

CN109903875A - A kind of method for solidifying boron-containing nuclear waste liquid by phosphate polymer

Info

Publication number: CN109903875A
Application number: CN201910148097.3A
Authority: CN
Inventors: 徐中慧; 姚正珍; 帅勤; 彭熙; 安然; 蒋鑫; 李宇; 陈筱悦
Original assignee: Southwest University of Science and Technology
Current assignee: Southwest University of Science and Technology
Priority date: 2019-02-28
Filing date: 2019-02-28
Publication date: 2019-06-18

Abstract

本发明公布了一种聚合物固化中低放射性核废液的方法，其实质是一种磷酸盐聚合物固化含硼核废液的方法。主要包括如下几个步骤：（1）浓磷酸溶液与浓缩后的含硼核废液按一定比例混合制备混合溶液；（2）以水玻璃和聚合氯化铝为原材料，盐酸为添加剂制备聚合物前驱体；（3）将步骤（1）中的混合溶液与步骤（2）中的聚合物前驱体按一定比例混合，搅拌均匀，制备含硼核废液固化体。该方法含硼核废液包容量大，不需要加碱中和，克服了水泥固化法缓凝作用强烈的缺陷，最终的固化体稳定性好，且制备工艺简单，成本低，无二次污染，易于工程化应用。The invention discloses a method for solidifying medium and low radioactive nuclear waste liquid by polymer, which is essentially a method for solidifying boron-containing nuclear waste liquid with phosphate polymer. It mainly includes the following steps: (1) The concentrated phosphoric acid solution and the concentrated boron-containing nuclear waste liquid are mixed in a certain proportion to prepare a mixed solution; (2) The polymer is prepared by using water glass and polyaluminum chloride as raw materials and hydrochloric acid as additives Precursor; (3) Mix the mixed solution in step (1) with the polymer precursor in step (2) in a certain proportion, stir evenly, and prepare a solidified body of boron-containing nuclear waste liquid. The method has a large capacity of the boron-containing nuclear waste liquid, does not need to add alkali for neutralization, overcomes the defect of the strong retardation effect of the cement solidification method, has good stability of the final solidified body, and has a simple preparation process, low cost and no secondary pollution. , easy for engineering application.

Description

A kind of method that phosphate polymer solidifies boracic nuclear waste

Technical field

The present invention relates to a kind of methods that phosphate polymer solidifies boracic nuclear waste, and it is useless to belong to a kind of middle low-activity nuclear Liquid solidification technology and Material Field.

Background technique

Global energy crisis has pushed the fast development of nuclear energy uses.While nuclear power industry high speed development, Spent Radioactive Object safe disposal problem is further prominent.Boracic nuclear waste is useless as the radioactive nucleus generated in pressurized-water reactor nuclear power plant operational process Liquid is mainly made of borate, a small amount of sodium nitrate and sodium phosphate, and acid stronger, salt content is high, and processing difficulty is big.Currently, nuclear power It stands and disposes the main thought of boracic nuclear waste are as follows: nuclear waste is concentrated-adds alkali neutralization-cement solidification-final disposal.

Cement solidification technique is that nuclear waste blending is formed to the process of solidified cement body in base-material.But conventional cement solidifies For technique when solidifying boracic nuclear waste, that there are quantity of alkali consumptions is big, at high cost, inclusion quantity is low, borate deferred action is strong, secondary The defects of pollution, it would be highly desirable to develop a kind of safe and efficient novel boracic nuclear waste curing process.

A.M. the scholars' studies have shown that carrying out cured process to radioactive waste using cement such as El-Kamash In, zeolite is added into ordinary portland cement, the compression strength of solidified cement body can be effectively improved and reduce radionuclide ion leaching Extracting rate, but the problems such as this method needs plus alkali neutralization, and quantity of alkali consumption is big, and there are slow settings.Chinese patent CN 101456715A is public Cloth is a kind of, and that leaching rate of the radionuclide in solidified cement body and addition lime are reduced by addition zeolite is solid to adjust Change the curing method of the setting time of body, but this method complex treatment process, needs to mix the addition such as water-reducing agent in disposal process Agent, it is at high cost.Chinese patent CN 105741899A disclose a kind of new radioactivity borate waste solution curing process additive, Curing formula and technique are accelerated hardening of cement using sodium metaaluminate and are condensed, added again by the way that borate is prepared into condensed borate The solidified body boric acid containing rate for adding the cured method of curing agent that can make preparation reaches 49.5%, can preferably make up conventional cement Solidify that containing rate is low and the strong defect of deferred action.But it is big, secondary that the technology still remains complex technical process, quantity of alkali consumption The disadvantages of pollution and high cost.

Above method is all made of alkaline cementitious material solidification boracic nuclear waste, but can not overcome simultaneously quantity of alkali consumption it is big, At high cost, the defects of inclusion quantity is low, borate deferred action is strong, secondary pollution.In order to make up the deficiency of cement solidification technology, The present invention proposes that using concentrated phosphoric acid as exciting agent, boracic nuclear waste is solvent, mixes, preparation contains with polymer precursor material Boron nuclear waste solidified body.Inventive polymers solidification process handles nuclear waste by curing agent of sour excited cementing material, solidifies Without adding alkali neutralization in journey, the cured deficiency of conventional cement can be made up.

Summary of the invention

The present invention provides a kind of method that phosphate polymer solidifies boracic nuclear waste, specific summary of the invention is as follows:

Boracic nuclear waste, concentrated phosphoric acid and polymer precursor after concentration is mixed with boracic nuclear waste solidified body by the present invention. Concentrated phosphoric acid and boracic nuclear waste provide strong acid and hypersaline environment for polymerization reaction, not only increase polymerization rate, also effective Shorten curing time.

Beneficial effects of the present invention:

(1) for curing process of the present invention without adding alkali neutralization, the acid medium for including using acid solution and boracic nuclear waste itself is molten Silane agent is solved, low energy consumption, and simple process is easy to engineer application；

(2) solidified body of the present invention does not need to be press-formed, and can voluntarily pour hardening；

(3) solidified body mechanical performance of the present invention and corrosion resistance are strong, and long-term safety stability is good, and containing rate is high, are conducive to contain The solidification of boron nuclear waste；

(4) whole preparation process and use process involved in the present invention are generated without any toxic pollutant, safety and environmental protection.

Specific embodiment

Case study on implementation 1:

A kind of method that phosphate polymer solidifies boracic nuclear waste, with Si/Al molar ratio be 0.5 by waterglass (m=3.17) and Aluminium polychloride mixing, is slowly added to hydrochloric acid (plural gel pH=3 ~ 4) while stirring, through suction filtration, washing, drying after 2 h of stirring And grinding process, 2 h are calcined under the conditions of 800 oC, 2 h of ball milling, obtains polymer precursor after cooled to room temperature, with Boracic nuclear waste, polybenzazole precursor body mass ratio 2:3:4 mixing after concentrated phosphoric acid (85 wt.%), concentration, stir moulding by casting system Standby solidified body, after conserving 28 d, compression strength is up to 32 MPa.According to PCT method in ASTM standard to solidified body anti-leaching performance It is analyzed, the Sr measured²⁺、Cs⁺Normalized leaching rate 10^-5Below.

Case study on implementation 2:

A kind of method that phosphate polymer solidifies boracic nuclear waste, with Si/Al molar ratio be 0.5 by waterglass (m=3.17) and Aluminium polychloride mixing, is slowly added to hydrochloric acid (plural gel pH=3 ~ 4) while stirring, through suction filtration, washing, drying after 2 h of stirring And grinding process, 2 h are calcined under the conditions of 800 oC, 2 h of ball milling, obtains polymer precursor after cooled to room temperature, with Boracic nuclear waste, polybenzazole precursor body mass ratio 1:1:1 mixing after concentrated phosphoric acid (85 wt.%), concentration, stir moulding by casting system Standby solidified body, after conserving 28 d, compression strength is up to 29 MPa.According to PCT method in ASTM standard to solidified body anti-leaching It can be carried out analysis, the Sr measured²⁺、Cs⁺Normalized leaching rate 10^-5Below.

Finally, it is stated that the above preferred implementation case is only used to illustrate the technical scheme of the present invention and not to limit it, although The present invention is described in detail by above-mentioned preferred implementation case, however, those skilled in the art should understand that, can To make various change to it in the form and details, without departing from claims of the present invention limited range.

Claims

1. The present invention discloses a method for solidifying medium and low radioactive nuclear waste liquid by polymer, which is essentially a method for solidifying boron-containing nuclear waste liquid with phosphate polymer. It mainly includes the following steps:

(1) Mix the concentrated phosphoric acid solution and the concentrated boron-containing nuclear waste liquid in a certain proportion to prepare a mixed solution;

(2) Use water glass and polyaluminum chloride as raw materials and hydrochloric acid as additives to prepare water glass-polyaluminum chloride composite gel, and prepare polymer precursors through suction filtration, washing, drying, grinding, calcination and ball milling;

(3) Mix the mixed solution in step (1) with the polymer precursor in step (2) in a certain proportion, stir evenly, and pour for curing.

2. according to the concentrated phosphoric acid solution described in claim 1, its main feature is as follows: the concentrated phosphoric acid solution mass percent concentration range is 85～95%.

3. The water glass according to claim 1, its main features are as follows: the water glass modulus range is 2.5～3.5.

4. according to the preparation of the polymer precursor described in claim 1, its main feature is as follows: water glass and polyaluminum chloride solution are uniformly mixed, and Si/Al mol ratio is=0.5～1; Slowly add hydrochloric acid while stirring , keep the pH value in the range of 3~4, and prepare water glass-polyaluminum chloride composite gel; after stirring for 2~5 h, carry out solid-liquid separation, and wash with deionized water for 2~3 times; The filter cake was dried in a drying oven at 105 ºC for 24 h, and then ground to powder; the dry gel powder was calcined at 800-1000 ºC for 2-5 h, and cooled to room temperature naturally; The colloidal powder was ball-milled for 2-5 h to obtain the polymer precursor.

5. according to the preparation of the mixed solution described in claim 1 and the solidified body of boron-containing nuclear waste liquid, its main features are as follows: m _{concentrated phosphoric acid} : m _{boron-containing nuclear waste liquid} =0.65～1.5; m _precursor : m _{mixed solution} =0.7~1.