阅读说明：本技术 一种从含铀碳酸钠溶液制备u3o8的方法 (Preparation of U from uranium-containing sodium carbonate solution3O8Method (2) ) 是由 周志全 任燕 曹令华 牛玉清 常喜信 邓慧东 赵凤岐 舒祖骏 曹笑豪 叶开凯 于 2020-04-24 设计创作，主要内容包括：本发明属于铀矿水冶技术领域,具体涉及一种从含铀碳酸钠溶液制备U<Sub>3</Sub>O<Sub>8</Sub>的方法,包括如下步骤：步骤一、碳酸钠体系高容量树脂吸附；步骤二、无结晶碳铵淋洗；步骤三、双部结晶；步骤四、蒸氨循环技术；采用该工艺过程,制备了品质合格的U<Sub>3</Sub>O<Sub>8</Sub>产品。采用pH调整,提高了树脂吸附的容量,提高了铀浓度,降低了蒸氨处理量；采用该发明推荐工艺参数、以及设备,避免了碳铵淋洗过程床层堵塞、管道堵塞问题。采用双部结晶工艺,提高了结晶效率,晶形良好,提高了结晶除杂效果。采用该工艺实现了无氨、无氯排放,氨全部循环。(The invention belongs to the technical field of uranium ore hydrometallurgy, and particularly relates to a method for preparing U from uranium-containing sodium carbonate solution 3 O 8 The method comprises the following steps: firstly, adsorbing by high-capacity resin of a sodium carbonate system; step two, leaching without crystallization ammonium bicarbonate; step three, double crystallization; step four, ammonia distillation circulation technology; by adopting the process, the qualified U is prepared 3 O 8 And (5) producing the product. The pH adjustment is adopted, so that the adsorption capacity of the resin is improved, the uranium concentration is improved, and the ammonia distillation treatment capacity is reduced; by adopting the method and the device, the problems of bed layer blockage and pipeline blockage in the ammonium bicarbonate leaching process are avoided. By adopting a double-part crystallization process, the crystallization efficiency is improved, the crystal form is good, and the crystallization and impurity removal effects are improved. The process realizes no ammonia and chlorine emission and complete ammonia circulation.)

1. Preparation of U from uranium-containing sodium carbonate solution₃O₈The method comprises the following steps: firstly, adsorbing by high-capacity resin of a sodium carbonate system; step two, leaching without crystallization ammonium bicarbonate; step three, double crystallization; step four, ammonia distillation circulation technology;

the method is characterized in that: firstly, adsorbing by high-capacity resin of a sodium carbonate system, a) adjusting the solution of uranium-containing carbonate solution, and adding NaOH or H₂SO₄Or CO₂Or NaHCO₃Or Na₂CO₃Or other acid and alkali, adjusting the pH value to 9-10.5, and improving the resin adsorption capacity under the system through pH adjustment;

b) and adsorbing uranium in the adjusting solution by using strong basic resin at room temperature, washing the saturated resin by using water, and returning the adsorption tail liquid and the washing liquid.

2. Preparation of U from a uranium containing sodium carbonate solution according to claim 1₃O₈The method of (2), characterized by: secondly, leaching without crystallization by ammonium bicarbonate;

preheating the resin tower, and keeping the temperature to stabilize the temperature to a certain value t1 and to be between 35 and 50 ℃. And (3) carrying out heat preservation leaching on the resin by adopting a hot ammonium bicarbonate leaching agent. Preheating the eluent to t1, wherein NH is contained in the eluent₄HCO₃The concentration is 90-150 g/L, (NH)₄)₂CO₃The concentration is 10-50 g/L, multiple towers are used for leaching in series, and the number of the towers N1 in series is 3-5.

3. Preparation of U from a uranium containing sodium carbonate solution according to claim 2₃O₈The method of (2), characterized by: the leaching adopts a single-tower leaching agent to carry out cyclic leaching, the cyclic leaching frequency n1 is 3-5, and the leaching agent needs to be preheated t1 every time.

4. Preparation of U from a uranium containing sodium carbonate solution according to claim 1₃O₈The method of (2), characterized by: step three, double crystallization;

a) and naturally cooling and crystallizing the leached qualified liquid to generate AUC crystals. AUC crystals and a cooling crystallization mother liquor are obtained after filtration;

b) cooling crystallization mother liquor, heating and distilling ammonia, decomposing ammonium bicarbonate, generating precipitation of uranium, and carrying out solid-liquid separation;

c) adding the precipitate into ammonium bicarbonate and AUC crystal, transforming to generate AUC, controlling the residual ammonium bicarbonate to be more than or equal to 200g/L, carrying out solid-liquid separation, and returning AUC mother liquor to prepare the eluent.

5. Preparation of U from a uranium containing sodium carbonate solution according to claim 1₃O₈The method of (2), characterized by: step four, ammonia distillation circulation technology;

a) cooling the crystallization mother liquor, heating and distilling ammonia, absorbing with water to obtain ammonium bicarbonate solution, adding NaOH into the ammonia distillation residual liquid to carry out secondary ammonia distillation, and adjusting acid or not adjusting acid to return after the secondary ammonia distillation according to needs;

b) calcining AUC in air atmosphere to obtain U₃O₈During calcining AUC, the flue gas needs to absorb and recover carbonic acid and ammonia in the flue gas, and the recovered ammonium carbonate needs to be prepared by using an eluent.

6. Preparation of U from a uranium containing sodium carbonate solution according to claim 1₃O₈The method is characterized in that the concentration of uranium is 4g/L, the total carbonate is 1mol/L, the pH is 9, NaOH is added to adjust the pH to 10, the adjusted solution is absorbed by 201 × 7 resin, the resin capacity after absorption is 54mg/ml, after the absorption tail liquid is discharged from a resin tower, the resin is washed by water, the washing volume is 1BV, saturated resin is obtained, and the absorption tail liquidReturning the washing liquid to the adsorption preorder process;

the saturated resin is leached by ammonium carbonate, a cyclic leaching process is adopted for 3 times, a resin tower is heated and kept at 40 ℃ before leaching, pipelines are heated with heat, the temperature of the eluting agent is heated to 40 ℃ before feeding, and the concentration of the eluting agent is 110g/LNH₄HCO₃+30g/L(NH₄)₂CO₃The leached qualified liquid enters a cooling crystallization tank, is slowly stirred and is reduced to room temperature, and is filtered to obtain AUC crystals, the concentration of uranium in the solution is 4g/L, ammonia distillation and uranium precipitation are removed, the solution is heated at 97 ℃ in a 3-stage reaction kettle, feeding is continuous, the obtained uranium precipitate is intermittently discharged, ammonia distillation residual liquid is continuously discharged, NaOH is added into the ammonia distillation residual liquid to carry out secondary ammonia distillation, the secondary ammonia distillation residual liquid is returned to the previous process of adsorption, and ammonia gas and carbon dioxide gas are absorbed by water in an absorption tower to obtain 450g/L ammonium carbonate solution;

adding 450g/L ammonium carbonate solution into the evaporated uranium ammonia precipitate, adding a small amount of AUC crystals, stirring and transforming to control the concentration of the remaining ammonium carbonate to be 240g/L, filtering after the reaction is finished to obtain AUC crystals and AUC mother liquor, returning the AUC mother liquor to prepare an eluent, and calcining all AUC crystals in a calciner to produce U₃O₈And the product, calcined ammonia gas and carbon dioxide enter an absorption tower to be absorbed.

7. Preparation of U from a uranium containing sodium carbonate solution according to claim 1₃O₈The method is characterized in that the concentration of uranium is 2g/L, the total carbonate is 0.8mol/L, the pH is 8.5, NaOH is added to adjust the pH to 9.5, the adjusted solution is absorbed by 201 × 7 resin, the resin capacity after absorption is 42mg/ml, after the absorption tail liquid is discharged from a resin tower, the resin is washed by water, the washing volume is 0.5BV, saturated resin is obtained, and the absorption tail liquid and the washing liquid are returned to the previous working procedure;

the saturated resin is leached by ammonium carbonate, a 3-tower series leaching process is adopted, the resin tower is heated and kept at 37 ℃ before leaching, the pipeline is heated, the temperature is kept at 37 ℃, the eluent is heated to 37 ℃ before feeding, and the concentration of the eluent is 110g/LNH₄HCO₃+20g/L(NH₄)₂CO₃The qualified drip washing liquid enters cooling crystallizationThe method comprises the following steps of (1) carrying out tank operation, stirring slowly to reduce the temperature to room temperature, filtering to obtain AUC crystals, removing ammonia distillation to precipitate uranium, heating at 97 ℃ in a 4-stage reaction kettle, feeding continuously, discharging obtained uranium precipitates intermittently, discharging ammonia distillation raffinate continuously, adding NaOH into the ammonia distillation raffinate to carry out secondary ammonia distillation, returning the secondary ammonia distillation raffinate to a preorder process, and absorbing ammonia gas and carbon dioxide gas by water in an absorption tower to obtain 420g/L ammonium carbonate solution;

adding 420g/L ammonium carbonate solution into the ammonia-evaporated uranium precipitate, adding a small amount of AUC crystals, stirring and transforming to control the concentration of the remaining ammonium carbonate to be 220g/L, filtering after the reaction is finished to obtain AUC crystals and AUC mother liquor, returning the AUC mother liquor to prepare an eluent, and calcining all AUC crystals in a calciner to produce U₃O₈And the product, calcined ammonia gas and carbon dioxide enter an absorption tower to be absorbed.

8. Preparation of U from a uranium containing sodium carbonate solution according to claim 1₃O₈The method is characterized in that the concentration of uranium is 1g/L, the total carbonate is 1mol/L, the pH is 9, NaOH is added to adjust the pH to 10, 201 × 7 resin is used for absorbing the adjusted solution, the resin capacity after absorption is 36mg/ml, after the absorption tail liquid is discharged from a resin tower, water is used for washing the resin, the washing volume is 1BV, saturated resin is obtained, and the absorption tail liquid and the washing liquid are returned to the leaching process;

the saturated resin is leached by ammonium carbonate, a cyclic leaching process is adopted for 2 times, a resin tower is heated and kept at 40 ℃ before leaching, pipelines are heated with heat, the temperature of the eluting agent is heated to 40 ℃ before feeding, and the concentration of the eluting agent is 110g/LNH₄HCO₃+30g/L(NH₄)₂CO₃The leached qualified liquid enters a cooling crystallization tank, is slowly stirred and is reduced to room temperature, and is filtered to obtain AUC crystals, the uranium concentration of the solution is 3.5g/L, ammonia distillation and uranium precipitation are removed, the solution is heated in a 4-stage reaction kettle at 95 ℃, feeding is continuous, the obtained uranium precipitate is intermittently discharged, ammonia distillation residual liquid is continuously discharged, NaOH is added into the ammonia distillation residual liquid to carry out secondary ammonia distillation, the secondary ammonia distillation residual liquid is returned to a leaching process, and ammonia gas and carbon dioxide gas are absorbed by water in an absorption tower to obtain 480g/L of ammonium carbonate solution;

adding 480g/L ammonium carbonate solution of ammonia into the uranium steaming sediment, adding a small amount of AUC crystals, stirring and transforming to control the concentration of the remaining ammonium carbonate to be 260g/L, filtering after the reaction is finished to obtain AUC crystals and AUC mother liquor, returning the AUC mother liquor to prepare an eluent, and calcining all AUC crystals in a calciner to produce U₃O₈And the product, calcined ammonia gas and carbon dioxide enter an absorption tower to be absorbed.

9. Preparation of U from a uranium containing sodium carbonate solution according to claim 1₃O₈The method is characterized in that the concentration of uranium is 10g/L, the total carbonate is 1mol/L, the pH is 10.5, sulfuric acid is added to adjust the pH to 10, 201 × 7 resin is used for absorbing the adjusted solution, the resin capacity after absorption is 36mg/ml, after the absorption tail liquid is discharged from a resin tower, water is used for washing the resin, the washing volume is 1BV, saturated resin is obtained, and the absorption tail liquid and the washing liquid are returned to the leaching process;

the saturated resin is leached by ammonium carbonate, a 4-time application circulation leaching process is adopted, a resin tower is heated and kept at 45 ℃ before leaching, pipelines are heated with heat, a leaching agent is heated to 45 ℃ before feeding, and the concentration of the leaching agent is 130g/LNH₄HCO₃+15g/L(NH₄)₂CO₃The leached qualified liquid enters a cooling crystallization tank, is slowly stirred and is reduced to room temperature, and is filtered to obtain AUC crystals, the uranium concentration of the solution is 5.5g/L, ammonia distillation and uranium precipitation are removed, the solution is heated in a 4-stage reaction kettle at 97 ℃, feeding is continuous, the obtained uranium precipitate is intermittently discharged, ammonia distillation raffinate is continuously discharged, NaOH is added into the ammonia distillation raffinate to carry out secondary ammonia distillation, the secondary ammonia distillation raffinate returns to a leaching process, and ammonia gas and carbon dioxide gas are absorbed by water in an absorption tower to obtain 480g/L of ammonium carbonate solution;

adding 480g/L ammonium carbonate solution of ammonia into the uranium steaming sediment, adding a small amount of AUC crystals, stirring and transforming to control the concentration of the remaining ammonium carbonate to be 240g/L, filtering after the reaction is finished to obtain AUC crystals and AUC mother liquor, returning the AUC mother liquor to prepare an eluent, and calcining all AUC crystals in a calciner to produce U₃O₈And the product, calcined ammonia gas and carbon dioxide enter an absorption tower to be absorbed.

Technical Field

The invention belongs to the technical field of uranium ore hydrometallurgy, and particularly relates to a method for preparing U from uranium-containing sodium carbonate solution₃O₈The method of (1).

Background

Preparation of U at present₃O₈The method mainly comprises the steps of preparing U from a uranium-containing sulfuric acid solution and preparing U from a sodium carbonate solution₃O₈The technology of (2) is less.

For sodium carbonate alkali leaching solution of uranium ore, there is a method of directly adding NaOH to precipitate SDU (sodium diuranate) to prepare U₃O₈Then, the SDU is dissolved in acid and precipitated with ammonia to prepare ADU, and then the ADU is calcined to obtain U₃O₈. The method has poor impurity removal effect, and impurities such as sodium are easy to exceed the standard.

For sulfuric acid systems, resin adsorption is generally employed. The system has certain difficulty if resin adsorption is adopted. Sodium carbonate can be generally used as an eluting agent, and the general adsorption effect of the sodium carbonate is not good when the sodium carbonate is directly adsorbed under the system.

The leaching of uranium-loaded resins with ammonium carbonate is also difficult. The leaching effect of low-concentration ammonium tartrate is poor, and AUC crystals (the solubility of ammonium salt of uranium is lower than that of sodium salt) are easily formed in uranium during the leaching process of high-concentration ammonium carbonate to block beds or pipelines. Generally, sodium chloride is adopted for leaching to form qualified leaching solution of sodium salt, and then ammonia is added into the leaching solution to prepare ADU. The method also has the problem that the impurities such as sodium and the like exceed the standard, and simultaneously has the problems that a large amount of chlorine-containing wastewater is difficult to treat and ammonia-containing wastewater is difficult to treat.

Disclosure of Invention

In view of the above disadvantages, the main object of the present invention is to provide a method for preparing U from uranium-containing sodium carbonate solution₃O₈OfThe method has good impurity removal effect, and qualified uranium products are prepared from the sodium carbonate solution; the method avoids the problem of chlorine-containing waste water; by adopting the method, the ammonia can be recycled, and the problem of ammonia-containing wastewater is avoided; the method can solve the problem of blockage of the elution crystallization of ammonium carbonate.

The technical scheme of the invention is as follows:

preparation of U from uranium-containing sodium carbonate solution₃O₈The method comprises the following steps: firstly, adsorbing by high-capacity resin of a sodium carbonate system; step two, leaching without crystallization ammonium bicarbonate; step three, double crystallization; step four, ammonia distillation circulation technology;

firstly, adsorbing by high-capacity resin of a sodium carbonate system, a) adjusting the solution of uranium-containing carbonate solution, and adding NaOH or H₂SO₄Or CO₂Or NaHCO₃Or Na₂CO₃Or other acid and alkali, adjusting the pH value to 9-10.5, and improving the resin adsorption capacity under the system through pH adjustment;

b) and adsorbing uranium in the adjusting solution by using strong basic resin at room temperature, washing the saturated resin by using water, and returning the adsorption tail liquid and the washing liquid.

Secondly, leaching without crystallization by ammonium bicarbonate;

preheating the resin tower, and keeping the temperature to stabilize the temperature to a certain value t1 and to be between 35 and 50 ℃. And (3) carrying out heat preservation leaching on the resin by adopting a hot ammonium bicarbonate leaching agent. Preheating the eluent to t1, wherein NH is contained in the eluent₄HCO₃The concentration is 90-150 g/L, (NH)₄)₂CO₃The concentration is 10-50 g/L, multiple towers are used for leaching in series, and the number of the towers N1 in series is 3-5;

the leaching adopts a single-tower leaching agent to carry out cyclic leaching, the cyclic leaching frequency n1 is 3-5, and the leaching agent needs to be preheated t1 every time.

Step three, double crystallization;

a) and naturally cooling and crystallizing the leached qualified liquid to generate AUC crystals. AUC crystals and a cooling crystallization mother liquor are obtained after filtration;

b) cooling crystallization mother liquor, heating and distilling ammonia, decomposing ammonium bicarbonate, generating precipitation of uranium, and carrying out solid-liquid separation;

c) adding the precipitate into ammonium bicarbonate and AUC crystal, transforming to generate AUC, controlling the residual ammonium bicarbonate to be more than or equal to 200g/L, carrying out solid-liquid separation, and returning AUC mother liquor to prepare the eluent.

Step four, ammonia distillation circulation technology;

a) cooling the crystallization mother liquor, heating and distilling ammonia, absorbing with water to obtain ammonium bicarbonate solution, adding NaOH into the ammonia distillation residual liquid to carry out secondary ammonia distillation, and adjusting acid or not adjusting acid to return after the secondary ammonia distillation according to needs;

b) calcining AUC in air atmosphere to obtain U₃O₈During calcining AUC, the flue gas needs to absorb and recover carbonic acid and ammonia in the flue gas, and the recovered ammonium carbonate needs to be prepared by using an eluent.

The invention has the beneficial effects that:

(1) by adopting the process, the qualified U is prepared₃O₈And (5) producing the product.

(2) The pH adjustment is adopted, so that the adsorption capacity of the resin is improved, the uranium concentration is improved, and the ammonia distillation treatment capacity is reduced;

(3) by adopting the method and the device, the problems of bed layer blockage and pipeline blockage in the ammonium bicarbonate leaching process are avoided.

(4) By adopting a double-part crystallization process, the crystallization efficiency is improved, the crystal form is good, and the crystallization and impurity removal effects are improved.

(5) The process realizes no ammonia and chlorine emission and complete ammonia circulation.

Drawings

FIG. 1 shows a process for preparing U from a uranium-containing sodium carbonate solution according to the invention₃O₈The flow chart of the sodium carbonate system high-capacity resin adsorption method in the method (1);

FIG. 2 shows a process for preparing U from a uranium-containing sodium carbonate solution according to the invention₃O₈The flow chart of the leaching method of the ammonium bicarbonate without crystallization in the method of (1);

FIG. 3 shows a process for preparing U from a uranium-containing sodium carbonate solution according to the invention₃O₈Is shown in the method flow chart.

Detailed Description

The invention is described in further detail below with reference to the figures and the embodiments.