阅读说明：本技术 一种高矿化度地下水铀矿的地浸采铀浸出方法 (In-situ leaching uranium extraction leaching method for high-mineralization-degree underground water uranium ore ) 是由 廖文胜 王立民 杜志明 于 2019-10-23 设计创作，主要内容包括：一种高矿化度地下水铀矿的地浸采铀浸出方法,包括以下步骤：步骤1:分析矿层地下水组成步骤2：开始抽注循环步骤3：待步骤2中浸出液pH值下降后,浸出剂中同时加入O<Sub>2</Sub>和CO<Sub>2</Sub>,经混合后注入矿层进行浸出步骤4：当步骤3中浸出液的残余氧浓度达到15mg/L时,注氧浓度降低至300～500mg/L；当浸出率达到65％时,注入氧气降低至50～200mg/L,直至浸出结束；步骤5：当步骤3-4中浸出液铀浓度大于10mg/L时,浸出液进塔吸附。(An in-situ leaching uranium extraction leaching method for high-salinity groundwater uranium ores comprises the following steps: step 1, analyzing the composition of underground water in a mineral layer, and step 2: starting a pumping cycle step 3: after the pH value of the leaching solution is reduced in the step 2, adding O into the leaching agent at the same time 2 And CO 2 And after mixing, injecting the mixture into an ore bed for leaching, wherein the leaching step 4 is as follows: when the residual oxygen concentration of the leaching solution in the step 3 reaches 15mg/L, the oxygen injection concentration is reduced to 300-500 mg/L; when the leaching rate reaches 65%, reducing the injected oxygen to 50-200 mg/L until the leaching is finished; and 5: and (4) when the uranium concentration of the leachate is more than 10mg/L in the step 3-4, feeding the leachate into a tower for adsorption.)

1. An in-situ leaching uranium extraction leaching method for high-mineralization-degree underground water uranium ores is characterized by comprising the following steps: the method comprises the following steps:

step 1, analyzing the composition of underground water in a mineral layer, and determining the bicarbonate content, the pH value and the concentration of other easily precipitated ions;

step 2: starting pumping and injecting circulation, and adding CO with the concentration of 800-1500 mg/L into underground water of a mineral bed₂Mixing uniformly, injecting into underground ore bed through injection pipeline to reduce pH of underground water in ore bedThe height is 0.1-0.2, and the time is controlled to be 15-20 days;

and step 3: after the pH value of the leaching solution is reduced in the step 2, adding O into the leaching agent at the same time₂And CO₂Mixing and injecting into the ore bed for leaching;

and 4, step 4: when the residual oxygen concentration of the leaching solution in the step 3 reaches 15mg/L, the oxygen injection concentration is reduced to 300-500 mg/L; when the leaching rate reaches 65%, reducing the injected oxygen to 50-200 mg/L until the leaching is finished;

and 5: and (4) when the uranium concentration of the leachate is more than 10mg/L in the step 3-4, feeding the leachate into a tower for adsorption.

2. The in-situ leaching uranium leaching method for uranium ores with hypersalinity groundwater according to claim 1, wherein the method comprises the following steps: in the step 1, the other easily-precipitated ions comprise HCO₃ ^-、Ca²⁺、Mg²⁺、SO₄ ^2-、∑Fe、Cl^-。

3. The in-situ leaching uranium leaching method for uranium ores with hypersalinity groundwater according to claim 1, wherein the method comprises the following steps: in said step 3, O₂And CO₂The injection pressure of (2) is higher than the pressure of the injection by 0.05MPa or more.

4. The in-situ leaching uranium leaching method for uranium ores with hypersalinity groundwater according to claim 1, wherein the method comprises the following steps: in the step 3, the oxygen injection concentration is 650-1000 mg/L, and CO is added₂The concentration is 800-1500 mg/L.

5. The in-situ leaching uranium leaching method for uranium ores with hypersalinity groundwater according to claim 1, wherein the method comprises the following steps: in the step 4, when the pH value of the leaching solution in the step 3 is reduced to 6.5, CO is added₂The concentration is reduced to 300-500 mg/L, if the pH of the leaching solution is continuously reduced, CO is reduced₂The concentration is reduced to 100-200 mg/L.

When the pH value in the leaching solution is reduced to 6.5, CO is added₂The concentration is reduced to 500mg/L, the pH of the leaching solution is continuously reduced to 6.3, and CO is removed₂The concentration is reduced to 200mg/L, and the pH is maintained between 6.0 and 6.2.

6. The in-situ leaching uranium leaching method for uranium ores with hypersalinity groundwater according to claim 1, wherein the method comprises the following steps: in the step 4, the bicarbonate concentration in the leachate is controlled to be about 1.0-1.2g/L, for example, less than 1g/L, and 200-500 mg/L bicarbonate is added to maintain a stable bicarbonate concentration.

7. The in-situ leaching uranium leaching method for uranium ores with hypersalinity groundwater according to claim 1, wherein the method comprises the following steps: in the step 5, weak-base anion exchange resin is adopted for adsorption.

8. The in-situ leaching uranium leaching method for uranium ores with hypersalinity groundwater according to claim 7, wherein the method comprises the following steps: the weak base anion exchange resin is JH-1 type resin, is an acrylic acid copolymerization crosslinking framework with a macroporous structure, and has an exchange group of-NH₂And substituted amine-NHR 1, the mass exchange capacity is 2.75mmol/ml, the granularity is 0.60-1.25mm, the wet apparent density is 0.68-0.76g/ml, the wet true density is 1.05-1.14g/ml, and the infiltration grinding ball rate is more than or equal to 90%.

9. The in-situ leaching uranium leaching method for uranium ores with hypersalinity groundwater according to claim 1, wherein the method comprises the following steps: in the steps 1-5, saturated resin and adsorption tail liquid are obtained by adsorption, and CO is added into the adsorption tail liquid after treatment₂And O₂And then re-injecting into the seam.

10. The in-situ leaching uranium leaching method for uranium ores with hypersalinity groundwater according to claim 1, wherein the method comprises the following steps: o of said step 3₂The filling concentration does not form air blockage.

Technical Field

The invention belongs to the field of in-situ leaching uranium mining, and particularly relates to an in-situ leaching uranium mining extraction method for high-salinity underground water uranium ore.

Background

In-situ leaching uranium mining is the most important mining method for natural uranium in the world and China. In the current method for extracting uranium by in-situ leaching in China, CO₂+O₂The in-situ leaching uranium mining process is the first choice for uranium deposit mining. CO in the process₂Often used to control pH and form bicarbonate to complex dissolved hexavalent uranium, and O₂The oxidation of uranium quadrivalent minerals to soluble hexavalent uranium as an oxidant is the key to the feasibility of the process.

However, for uranium deposits with high groundwater mineralization in some deposits, in-situ leaching of uranium results in an increase in groundwater ion concentration,particularly, the increase of bicarbonate radical, calcium, magnesium and sulfate radical is easy to precipitate and block the ore bed, the pumping and injection liquid amount is reduced, and the leaching effect is influenced; in addition, the underground water has high mineralization degree and strong buffering effect, so that CO is generated₂And O₂After addition, there is relatively little variation in the seam, resulting in leaching difficulties. For the ore deposit, a mining method (CN 101429860B) for desalting less reagents is provided, the ion concentration and the mineralization degree of underground water are reduced by additionally adding desalted water, but the method obviously improves the mining cost and enlarges the leaching range; moreover, the reduced degree of mineralization will also deteriorate the permeability properties of the mineral seam.

For leaching agent O₂And CO₂CN106507867B proposes O₂And CO₂The addition amount is controlled to be 100-300 mg/L, and the pH value of the leaching solution is 6.0-8.5; CN101429860B proposes O₂The concentration is 150-450 mg/L, and the pH is controlled to be less than or equal to 6.9; CN102900418B requires gradient oxygen addition, wherein the initial concentration is 400-500 mg/L, the subsequent concentration is 200mg/L, the final concentration is 50-150 mg/L, and the pH value is controlled to be 7-8; CN106507865B adopts oxygen injection method for high carbonate underground water deposit, the initial oxygen injection concentration is 400mg/L, then the initial oxygen injection concentration is reduced to 200mg/L, and finally the initial oxygen injection concentration is reduced to 50-150 mg/L, HCO₃ ^-The concentration is maintained between 1.0 and 1.3 g/L; CN107130122B proposes an enhanced leaching technique after primary leaching, requiring the addition of oxygen and CO₂The concentration is 400-600 mg/L.

The leaching process has a good effect on the conventional sandstone uranium ore, but has a long leaching period, a low leaching solution concentration and serious deposit blockage according to the conventional process on the sandstone uranium ore deposit with high mineralization degree of underground water and relatively good permeability. Aiming at the uranium ore body which is difficult to leach, a more effective leaching process is needed to improve the leaching efficiency.

Disclosure of Invention

The invention aims to: the in-situ leaching uranium extraction leaching method for high-salinity underground water uranium ore adopts high-concentration oxygen at the initial stage as an oxidation reagent to quickly and efficiently oxidize an ore bed and controls CO through a process₂The pH value of the leaching solution is adjusted by the adding sequence and the adding amount, so that the leaching effect is ensured, and meanwhile, the blockage of an ore bed is avoidedAnd (5) problems are solved.

The technical scheme of the invention is as follows: an in-situ leaching uranium extraction leaching method for high-salinity groundwater uranium ores comprises the following steps:

step 1, analyzing the composition of underground water in a mineral layer, and determining the bicarbonate content, the pH value and the concentration of other easily precipitated ions;

step 2: starting pumping and injecting circulation, and adding CO with the concentration of 800-1500 mg/L into underground water of a mineral bed₂Uniformly mixing, injecting the mixture into an underground ore bed through a liquid injection pipeline, so that the pH value of underground water in the ore bed is reduced by 0.1-0.2, and the time is controlled to be 15-20 days;

and step 3: after the pH value of the leaching solution is reduced in the step 2, adding O into the leaching agent at the same time₂And CO₂Mixing and injecting into the ore bed for leaching;

and 4, step 4: when the residual oxygen concentration of the leaching solution in the step 3 reaches 15mg/L, the oxygen injection concentration is reduced to 300-500 mg/L; when the leaching rate reaches 65%, reducing the injected oxygen to 50-200 mg/L until the leaching is finished;

and 5: and (4) when the uranium concentration of the leachate is more than 10mg/L in the step 3-4, feeding the leachate into a tower for adsorption.

In the step 1, the other easily-precipitated ions comprise HCO₃ ^-、Ca²⁺、Mg²⁺、SO₄ ^2-、∑Fe、Cl^-。

In said step 3, O₂And CO₂The injection pressure of (2) is higher than the pressure of the injection by 0.05MPa or more.

In the step 3, the oxygen injection concentration is 650-1000 mg/L, and CO is added₂The concentration is 800-1500 mg/L.

In the step 4, when the pH value of the leaching solution in the step 3 is reduced to 6.5, CO is added₂The concentration is reduced to 300-500 mg/L, if the pH of the leaching solution is continuously reduced, CO is reduced₂The concentration is reduced to 100-200 mg/L.

When the pH value in the leaching solution is reduced to 6.5, CO is added₂The concentration is reduced to 500mg/L, the pH of the leaching solution is continuously reduced to 6.3, and CO is removed₂The concentration is reduced to 200mg/L, and the pH is maintained between 6.0 and 6.2.

In the step 4, the bicarbonate concentration in the leachate is controlled to be about 1.0-1.2g/L, for example, less than 1g/L, and 200-500 mg/L bicarbonate is added to maintain a stable bicarbonate concentration.

In the step 5, weak-base anion exchange resin is adopted for adsorption.

The weak base anion exchange resin is JH-1 type resin, is an acrylic acid copolymerization crosslinking framework with a macroporous structure, and has an exchange group of-NH₂And substituted amine-NHR 1, the mass exchange capacity is 2.75mmol/ml, the granularity is 0.60-1.25mm, the wet apparent density is 0.68-0.76g/ml, the wet true density is 1.05-1.14g/ml, and the infiltration grinding ball rate is more than or equal to 90%.

In the steps 1-5, saturated resin and adsorption tail liquid are obtained by adsorption, and CO is added into the adsorption tail liquid after treatment₂And O₂And then re-injecting into the seam.

O of said step 3₂The filling concentration does not form air blockage.

The invention has the following remarkable effects: the invention passes the initial high-concentration CO₂The pH value of the leaching agent is adjusted, so that the blockage of a leaching solution in an ore bed under the hypersalinity can be avoided, meanwhile, the lower pH value of the leaching solution is kept, the resin adsorption capacity is improved, and the addition of CO before entering a tower is avoided₂The step (2); the high-concentration oxygen in the initial stage is used as an oxidant, so that the buffering effect of a high-mineralization leaching solution can be eliminated, uranium minerals can be rapidly oxidized, the leaching effect is enhanced, and underground water high-mineralization and strong-reducibility refractory ore bodies can be effectively exploited.

Detailed Description

The method for in-situ leaching uranium mining from high-salinity groundwater uranium ore according to the invention is further described in detail with reference to specific examples.