CN109987738A - A kind of uranium recovery process from uranium-containing waste liquid - Google Patents

Abstract

The invention belongs to a uranium recovery process in uranium-containing waste liquid. (1) Adjust the pH value of uranium-containing wastewater; (2) Filtration of waste liquid; (3) Adsorption of waste liquid, uranium concentration ≥ 200 mg/L and then sent to the new adsorption material system, the clear liquid produced by the 2nd filtration and the 3rd filtration system The produced concentrated solution is sent back to the pre-filtration intermediate storage tank, and continues to be concentrated through the 1st filtration system. The concentration of uranium in the clear liquid produced by the 3rd filtration system is 0.02-0.03mg/L, and sent to the discharge tank for discharge, 3 The concentrate produced by the secondary filtration system has a uranium concentration of 200mg/L, which is adsorbed by a new type of uranium adsorption material; (4) After saturation, analysis is carried out, and finally a uranium-containing material with a uranium concentration of about 1-5g/L or more is produced. The advantages of the present invention are that the membrane treatment technology equipment is simple and can realize automatic control, normal temperature operation, no chemical change, low energy consumption, clean and pollution-free. Realize interlocking control to protect the membrane processing system safely.

Description

A kind of uranium recovery process from uranium-containing waste liquid

technical field

The invention belongs to a uranium recovery and purification process in uranium-containing waste water, in particular to a uranium recovery process in uranium-containing waste water.

Background technique

In the production process of natural uranium hexafluoride, a large amount of uranium-containing process waste liquid will be produced. The recycling and utilization of metallic uranium resources and the discharge of wastewater up to the standard are widely concerned in the industry.

Among the uranium-containing wastewater produced in the uranium conversion production process, especially the alkaline uranium-containing wastewater generated in the fluorination tail gas leaching process, the system is complex. The domestic resin selected by the currently used ion exchange technology for uranium removal is difficult to achieve the discharge target of <50μg/L, and a large amount of waste resin is generated which is difficult to handle. Through research, industrial adsorption materials at home and abroad (such as new resins, new synthetic fibers) can achieve wastewater discharge standards, but such materials are expensive and will increase the operating cost of wastewater treatment facilities. Therefore, the membrane treatment system is used in this design to achieve discharge of most of the wastewater, and a small amount of concentrated liquid produced by membrane treatment is treated with new adsorption materials. On the one hand, the use of adsorbent materials is reduced. The problem that the concentrate cannot meet the discharge standard.

Both domestic and foreign membrane treatment technology and ion exchange technology have successful experience in the treatment of uranium-containing wastewater. The patent of this invention is mainly aimed at the process design of uranium-containing wastewater treatment in domestic uranium conversion production lines, and the entire process can be optimally controlled.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a uranium recovery process in a uranium-containing waste liquid, and a membrane treatment system and a novel adsorption material are selected as the units of the uranium-containing wastewater treatment process, so as to achieve the purpose of uranium concentration < 50 μg/L after the uranium-containing wastewater treatment.

The present invention is achieved in this way, a uranium recovery process in a uranium-containing waste liquid, which comprises the following steps:

(1) Adjust the pH value of uranium-containing wastewater;

(2) Waste liquid filtration;

(3) Waste liquid adsorption, the uranium concentration ≥ 200mg/L is sent to the new adsorption material system, the clear liquid produced by the 2nd filtration and the concentrate produced by the 3rd filtration system are returned to the pre-filtration intermediate storage tank, and continue to pass through 1 The secondary filtration system is concentrated. The uranium concentration of the clear liquid produced by the 3rd filtration system is 0.02-0.03mg/L, which is sent to the discharge tank for discharge. The concentrate produced by the 3rd filtration system has a uranium concentration of 200mg/L. Uranium adsorption material adsorption;

(4) Perform analysis after saturation, and finally produce uranium-containing materials with a uranium concentration of about 1-5 g/L or more.

In the step (1), the uranium-containing wastewater is first adjusted to pH, and the pH is adjusted to less than 3.

In the step (2), the prepared waste liquid is sent to the 1st nanofiltration system, the concentrated liquid produced by the 1st filtration system is sent to the 2nd filtration system to continue to concentrate, and the clear liquid is sent to the 3rd nanofiltration system. Continue to concentrate; the concentrate produced by the secondary filtration system needs to be recycled.

In the 1st nanofiltration filtration system described in the step (2), the working temperature of the pump is less than 40°C, and the pressure of the pump is less than 2.0Mpa.

In the secondary nanofiltration filtration system described in the step (2), the working temperature of the pump is less than 40°C, and the pressure of the pump is less than 2.0Mpa.

In the secondary nanofiltration filtration system of the step (2), the working temperature of the pump is less than 50°C, and the pressure of the pump is less than 2.0Mpa.

The advantages of the present invention are that the membrane treatment technology equipment is simple and can realize automatic control, normal temperature operation, no chemical change, low energy consumption, clean and pollution-free. Realize interlocking control to protect the membrane processing system safely.

Detailed ways

The present invention is described in detail below in conjunction with specific embodiments:

A uranium recovery process in a uranium-containing waste liquid, which comprises the following steps:

(1) Adjust the pH value of the uranium-containing wastewater, first adjust the pH of the uranium-containing wastewater, and adjust the pH to less than 3;

(2) Filtration of waste liquid, the prepared waste liquid is sent to the primary nanofiltration filtration system (the working temperature of the pump is less than 40°C, and the pump pressure is less than 2.0Mpa), and the concentrated solution produced by the primary filtration system (the uranium concentration is about 20- 50mg/L) to the 2nd filtration system (pump working temperature <40℃, pump pressure less than 2.0Mpa) to continue enrichment, the clear liquid (uranium concentration <10mg/L) is sent to the 3rd nanofiltration filtration system (pump working temperature <50°C, pump pressure less than 2.0Mpa) to continue to concentrate; the concentrate produced by the secondary filtration system needs to be recycled;

(3) Waste liquid adsorption, the uranium concentration ≥ 200mg/L is sent to the new adsorption material system, the clear liquid produced by the 2nd filtration and the concentrate produced by the 3rd filtration system are returned to the pre-filtration intermediate storage tank, and continue to pass through 1 The secondary filtration system is concentrated. The uranium concentration of the clear liquid produced by the 3rd filtration system is about 0.02-0.03mg/L, which is sent to the discharge tank for discharge. The concentrate produced by the 3rd filtration system has a uranium concentration of 200mg/L. Adsorption of new uranium adsorption materials;

(4) Perform analysis after saturation, and finally produce uranium-containing materials with a uranium concentration of about 1-5 g/L or more.

According to this technical scheme, continuous treatment of uranium-containing wastewater can be realized, and the flow of clear liquid produced by 3 times of filtration is regarded as the treatment capacity of the system. The 1st and 2nd filtration are designed through the membrane system selection to realize the continuous cycle operation of the whole system. In addition, the membrane units, pipes, pumps, valves and containers in the system are made of acid-resistant materials, and at the same time, in order to protect the system, an interlocking pump stop design is required for each feeding tank.

Pretreatment mainly refers to mechanical filtration, which is to remove suspended solids, colloids, turbidity, chromaticity, odor and other substances in the raw solution, large particles of impurities, clay and a very small amount of colloids and other substances, to prevent these substances from affecting the ultrafiltration in the later stage. Filtration, reverse osmosis membrane effect. The main filtration methods are disc filtration and bag filtration. The material of the treatment system membrane is polypropylene, which has strong acid and alkali resistance.

Microfiltration is a membrane separation technology that uses the size of the pore size and the pressure difference as the driving force to intercept suspended substances such as particles in the solution that are larger than the pore size of the membrane, so as to achieve the removal of particles and the clarification of the solution. The pore size of the microporous membrane used in the present invention is 1 μm (the filter element is used in the microfiltration, and the large particle suspended matter in different ranges can be separated according to the difference of the filter element), the suitable pH value range is 0-14, and the temperature is (5 ~ 50) ℃, can retain clay, suspended solids and other substances, can play a protective role in the subsequent ultrafiltration, nanofiltration and reverse osmosis membranes. Since the particles removed by microfiltration are usually much larger than the solutes and macromolecules separated by reverse osmosis and ultrafiltration, there is no osmotic pressure, and the operating pressure difference is small, about (0.01-0.2) MPa.

Nanofiltration membrane is a pressure-driven membrane between reverse osmosis and ultrafiltration membrane, and it is one of the fastest developing membrane brands in the world in recent years. Nanofiltration membranes with different molecular weight cut-offs have certain differences in the ions and other substances they filter. When the solution passes through the nanofiltration membrane, under the action of pressure, the substances that can pass through the nanofiltration membrane are separated from the permeate, and the part that cannot pass through is retained.

The materials of the nanofiltration membranes used in the present invention are polyamide composite membranes, and their molecular weight cutoffs are 300 Daltons (primary nanofiltration membranes), 200 Daltons (secondary nanofiltration membranes) and 200 Daltons (tertiary nanofiltration membranes), respectively. Nanofiltration). The suitable operating temperature of nanofiltration membrane is (5～45)℃. The working pressure is selected according to the membrane filtration area and processing capacity. The pH value range of continuous operation is 2～11.

Claims (6)

1. uranium recovery process in a kind of uranium-bearing waste liquid, it is characterised in that: it includes the following steps,

(1) uranium-containing waste water pH value is adjusted；

(2) waste liquid filters；

(3) waste liquid adsorbs, and the clear liquid generated to novel absorption material system, 2 filterings and 3 times are sent after uranium concentration >=200mg/L The dope that filtration system generates is returned and is recycled in pre-filtering intermediate storage tank, is continued through 1 filtration system and is carried out concentration, and 3 The clear liquid uranium concentration that secondary filtration system generates is 0.02-0.03mg/L, send to blowdown vessel and is discharged, and 3 times filtration system generates Dope, uranium concentration 200mg/L, using Novel Uranium adsorbent material adsorb；

(4) it is parsed after being saturated, it is final to generate the uranium-containing materials that uranium concentration is about 1-5g/L or more.

2. uranium recovery process in a kind of uranium-bearing waste liquid as described in claim 1, it is characterised in that: described step (1) uranium-bearing Waste water first carries out PH adjusting, and PH is adjusted to less than 3.

3. uranium recovery process in a kind of uranium-bearing waste liquid as described in claim 1, it is characterised in that: the step (2) will be adjusted The waste liquid prepared is sent to 1 nanofiltration filtration system, the dope that 1 filtration system generates send to 2 filtration systems continue it is dense Contracting, clear liquid, which is sent to 3 nanofiltration filtration systems, to be continued to be concentrated；The dope that 2 filtration systems generate need to carry out circular treatment.

4. uranium recovery process in a kind of uranium-bearing waste liquid as described in claim 1, it is characterised in that: the step (2) is described 1 nanofiltration filtration system, 40 DEG C of pump work temperature <, pump pressure be less than 2.0Mpa.

5. uranium recovery process in a kind of uranium-bearing waste liquid as described in claim 1, it is characterised in that: the step (2) is described 2 nanofiltration filtration systems, 40 DEG C of pump work temperature <, pump pressure be less than 2.0Mpa.

6. uranium recovery process in a kind of uranium-bearing waste liquid as described in claim 1, it is characterised in that: the step (2) is described 2 nanofiltration filtration systems, 50 DEG C of pump work temperature <, pump pressure be less than 2.0Mpa.