Pipe leaching method for ionic rare earth ore

Abstract

The present invention discloses a pipeline leaching method for ionic rare earth ores. Ionic rare earth leaching tailings are loaded into a pipeline, followed by ionic rare earth ore. The loading ratio of ore to tailings, the pipeline aspect ratio, and the negative pressure at the pipeline outlet are controlled. A leaching agent is then added at the pipeline inlet for leaching, and the rare earth leachate at the outlet is collected in sections. This method utilizes the differences in the adsorption properties of clay minerals for rare earth elements and employs pipeline leaching to increase the number of adsorption, desorption, and ion exchange cycles of rare earth elements in the clay minerals. Simultaneously, the ionic leaching tailings are initially added to the pipeline to achieve re-adsorption and re-desorption of the rare earth elements, effectively increasing the separation coefficients between rare earth elements and between rare earth elements and non-rare earth elements. Ultimately, while ensuring the loading volume and pipeline aspect ratio, the rare earth elements are pre-grouped and the concentration of the rare earth leachate is effectively increased.

Description

Technical Field

[0001] The present invention relates to the field of rare earth extraction and recovery, and in particular to a pipeline leaching method for ionic rare earth ores. Background Art

[0002] Ionic rare earth ores are rich in medium and heavy rare earth elements and possess extremely high economic value, making them a valuable strategic mineral resource in my country. Ionic rare earth ores typically contain 0.05-0.20 wt% rare earth elements (calculated as rare earth oxides). Based on the rare earth element's presence in the mineral, they can be divided into four types: water-soluble phase (<0.01%), ionic phase (50%-85%), colloidal phase (5%-10%), and mineral phase (10%-45%). Ionic rare earth elements are those adsorbed on the surface of clay minerals in the form of easily leached hydrated cations or hydroxyl hydrated cations. Because ionic rare earth elements primarily exist in a hydrated ionic state, their extraction requires ion exchange, not conventional physical separation methods such as gravity separation, magnetic separation, flotation, or electrostatic separation. Consequently, direct leaching of rare earth elements with electrolyte solutions is typically used for extraction.

[0003] However, due to the low grade of ionic rare earth ore and the thin thickness of the mine weathering layer, whether ammonium sulfate or magnesium sulfate is used as the leaching agent for ionic rare earth ore, the rare earth concentration in the leachate is not high, basically below 1.0g / L; the subsequent rare earth enrichment by extraction or precipitation has problems such as large water phase and low efficiency. In order to solve the problem of low rare earth leaching rate and low leachate concentration in ionic rare earth ore, researchers have developed many rare earth enhanced leaching processes, including Fe 2+ 、Al 3+ Although non-ammonia leaching agents such as fulvic acid, ammonium formate, and ammonium citrate can effectively improve the leaching rate of rare earth, Fe 2+ 、Al 3+ Leaching agents lead to high concentrations of impurity ions in the leachate, increasing the burden of subsequent processing. Leaching aids such as fulvic acid and citrate can enhance the leaching of ionic rare earths by complexing with rare earth ions, thereby slightly increasing the concentration of the rare earth leachate. Additionally, physical methods such as ultrasound, magnetic fields, and electric fields have been used to enhance rare earth leaching, but these methods are limited by process equipment and complex leaching environments, hindering large-scale application. However, these methods only increase the rare earth concentration in the rare earth leachate, resulting in insignificant changes in rare earth distribution, and cannot achieve pre-grouping of rare earths to reduce the burden on rare earth smelting and separation processes.

[0004] Therefore, how to choose a suitable leaching method to effectively improve the rare earth leaching rate and the concentration of the rare earth leachate, and at the same time achieve pre-grouping of rare earth elements to improve the rare earth enrichment efficiency in the leachate and reduce the rare earth extraction and separation load, is a common concern in the mining process of ionic rare earth ores. Summary of the Invention

[0005] The main purpose of the present invention is to provide a pipeline leaching method for ionic rare earth ores to improve the rare earth leaching rate and the concentration of rare earth leachate, while achieving pre-grouping of rare earth elements.

[0006] To achieve the above-mentioned object, the present invention provides a pipeline leaching method for ionic rare earth ore. First, ionic rare earth leaching tailings are loaded into a pipeline, and then ionic rare earth ore is loaded into the pipeline, and the loading mass ratio of the ionic rare earth leaching tailings to the ionic rare earth ore is controlled to be ≥0.8:1; the aspect ratio of the pipeline is 2000-5000, and the overall loading height should be more than 1500 times the diameter of the pipeline; the pipeline outlet is controlled to be negative pressure, and then a leaching agent is added at the pipeline inlet to leaching the ore, and the rare earth leachate at the outlet is collected in sections, so as to obtain a high yttrium rare earth solution with a yttrium distribution of more than 80%, a high neodymium rare earth solution with a neodymium distribution of more than 70%, and a high lanthanum rare earth solution with a lanthanum distribution of more than 80%.

[0007] Furthermore, the leaching agent is a salt solution containing at least one of ammonium ions, magnesium ions, iron ions, and aluminum ions, and its cation concentration is 0.3-0.6 mol / L.

[0008] Furthermore, a water-soluble carboxylic acid compound is added to the leaching agent at a concentration of 0.005-0.02 mol / L. Preferably, the water-soluble carboxylic acid compound is at least one of sulfosalicylic acid, citric acid, and oxalic acid.

[0009] Furthermore, the negative pressure at the pipeline outlet is controlled to be 10Kpa-50Kpa.

[0010] The present invention utilizes the difference in the adsorption properties of clay minerals for rare earth elements and adopts a pipeline leaching method to increase the number of adsorption, desorption and other ion exchanges of rare earth elements in clay minerals. At the same time, ionic leaching tailings are first added to the pipeline to complete the re-adsorption and re-desorption of rare earth elements, effectively increasing the separation coefficient between rare earth elements and rare earth elements, and between rare earth elements and non-rare earth elements. Ultimately, under the conditions of ensuring the ore loading volume and the pipeline aspect ratio, the pre-grouping of rare earth elements is achieved, and the concentration of rare earth leachate is effectively increased. DETAILED DESCRIPTION

[0011] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the embodiments.

[0012] Ionic rare earth ores contain a large amount of clay minerals. The surface of clay minerals is negatively charged and easily absorbs positively charged ions by electrostatic action. Under normal circumstances, most of the rare earths in ionic rare earth ores are adsorbed by clay minerals in the form of simple hydrated or hydroxyl hydrated cations. The adsorbed rare earth ions are adsorbed by clay minerals in the presence of more chemically active cations (M: Na+, NH4 + Mg 2+ etc.) for exchange desorption, thereby realizing the leaching of ionic rare earth ores.

[0013] However, the charge, water and ion radius between rare earths and between rare earths and non-rare earth impurities are different, resulting in inconsistent surface charge density. Therefore, the adsorption capacity and properties of different elements are different. For example, Chi Ruan et al. calculated through quantum chemistry that the order of adsorption capacity of clay minerals for rare earth elements is: La 3+ >Ce 3+ >Pr 3+ >Nd 3+ >Sm 3+ >Eu 3+ >Gd 3+ >Tb 3+ >Dy 3+ >Ho 3+ >Y 3+ >Er 3+ >Tm 3+ >Yb 3+ >Lu 3+ He Qiang et al. used kaolin as a typical clay mineral and conducted adsorption, competitive adsorption and desorption experiments. The experiments showed that strong electrostatic attraction and concentration driving force are conducive to the adsorption of cations, and the adsorption capacity and competitive adsorption capacity of cations are determined by La 3+ 、Y 3+ 、Al 3+ Mg 2+ and NH4 + Because the adsorption capacities of various elements vary, when the same leaching agent is used, cations with weaker adsorption capacities are desorbed first, resulting in a certain fractionation effect. However, since clay minerals have relatively small adsorption capacities for different elements, conventional leaching methods are difficult to achieve pre-separation of rare earth elements, or rare earth elements, from non-rare earth elements.

[0014] To this end, the present invention provides a pipeline leaching method for ionic rare earth ore. First, ionic rare earth leaching tailings are loaded into a pipeline, and then ionic rare earth ore is loaded into the pipeline, and the loading mass ratio of the ionic rare earth leaching tailings to the ionic rare earth ore is controlled to be ≥0.8:1; the aspect ratio of the pipeline is 2000-5000, and the overall loading height should be more than 1500 times the pipeline diameter; the pipeline outlet is controlled to be negative pressure, and then a leaching agent is added at the pipeline inlet to leaching the ore, and the rare earth leachate at the outlet is collected in sections, so as to obtain a high yttrium rare earth solution with a yttrium distribution of more than 80%, a high neodymium rare earth solution with a neodymium distribution of more than 70%, and a high lanthanum rare earth solution with a lanthanum distribution of more than 80%. The pipeline leaching method is used, with the length-to-diameter ratio of the pipeline controlled at 2000-5000, and the overall loading height required to be at least 1500 times the pipeline diameter. This increases the number of adsorption, desorption, and ion exchange events of rare earth elements in clay minerals, ensuring a certain degree of separation between rare earth elements and between rare earth elements and non-rare earth elements. Furthermore, the pipeline is first loaded with ionic rare earth leaching tailings, followed by ionic rare earth ore. This allows the ions leached from the ore to be re-adsorbed and desorbed in the tailings. Ions with strong adsorption capacity are adsorbed first and desorbed later in the desorption process. By controlling the loading mass ratio of tailings to ore at 0.8:1, further separation of rare earth and non-rare earth ions in clay minerals is ensured. Since different ionic rare earth ores have different grades and distributions, it is necessary to test the rare earth leachate at different times and collect it at different stages to finally obtain a solution with high calcium ion content, a high yttrium distribution rare earth solution, a high praseodymium-neodymium distribution rare earth solution, and a high lanthanum distribution rare earth solution. The concentration can also reach more than 5g / L, which greatly improves the rare earth concentration of the leachate while realizing the pre-grouping of rare earth elements.

[0015] In the present invention, the leaching agent is a salt solution containing at least one of ammonium ions, magnesium ions, iron ions, and aluminum ions, with a cation concentration of 0.3-0.6 mol / L. The higher the concentration, the better the separation effect. Specifically, a water-soluble carboxylic acid compound is added to the leaching agent, with its concentration controlled to 0.005-0.02 mol / L. The addition of the carboxylic acid compound can increase the separation coefficient between rare earth elements and further strengthen the grouping of the elements. Preferably, the water-soluble carboxylic acid compound is at least one of sulfosalicylic acid, citric acid, and oxalic acid.

[0016] At the same time, in order to achieve normal flow of the leachate in a pipeline with a high aspect ratio, the negative pressure at the pipeline outlet needs to be controlled at 10KPa-50KPa. The higher the loading height and the smaller the pipeline diameter, the smaller the negative pressure needs to be controlled.

[0017] The pipeline leaching method for ionic rare earth ores provided by the present invention will be further described below with reference to examples.

[0018] Comparative Example 1

[0019] Ionic rare earth ore (medium yttrium-rich europium type) is loaded into a pipeline (inner diameter of the pipeline is 5 cm), the aspect ratio of the pipeline is 3000, and the height of the entire ore loading should be 2500 times the diameter of the pipeline; the negative pressure at the pipeline outlet is controlled to be 30KPa, and then 0.4mol / L magnesium sulfate leaching agent is added at the pipeline inlet for leaching, and the rare earth leachate at the outlet is collected in sections to obtain a high Y solution with a yttrium distribution of 67.1% and a concentration of 10.6g / L, a high neodymium rare earth solution with a neodymium distribution of 38.3% and a concentration of 5.1g / L, and a high lanthanum rare earth solution with a lanthanum distribution of 60.6% and a concentration of 8.7g / L.

[0020] Comparative Example 2

[0021] The ionic rare earth leaching tailings are loaded into a pipeline, and then the ionic rare earth ore (medium yttrium-rich europium type) is loaded into the pipeline (the inner diameter of the pipeline is 5 cm), and the loading mass ratio of the ionic rare earth leaching tailings and the ionic rare earth ore is controlled to be 1:1; the aspect ratio of the pipeline is 1000, and the overall loading height should be 2500 times the diameter of the pipeline; the negative pressure at the pipeline outlet is controlled to be 30Kpa, and then 0.4mol / L magnesium sulfate leaching agent is added at the pipeline inlet for leaching, and the rare earth leachate at the outlet is collected in sections to obtain a high Y solution with a yttrium distribution of 41.3% and a concentration of 4.1g / L, a high neodymium rare earth solution with a neodymium distribution of 28.5% and a concentration of 2.2g / L, and a high lanthanum rare earth solution with a lanthanum distribution of 49.4% and a concentration of 3.4g / L.

[0022] Example 1

[0023] The ionic rare earth leaching tailings are loaded into a pipeline, and then the ionic rare earth ore (medium yttrium-rich europium type) is loaded into the pipeline (the inner diameter of the pipeline is 5 cm), and the loading mass ratio of the ionic rare earth leaching tailings and the ionic rare earth ore is controlled to be 1:1; the aspect ratio of the pipeline is 3000, and the overall loading height should be 2500 times the diameter of the pipeline; the negative pressure at the pipeline outlet is controlled to be 30Kpa, and then 0.4mol / L magnesium sulfate leaching agent is added at the pipeline inlet for leaching, and the rare earth leachate at the outlet is collected in sections to obtain a high yttrium rare earth solution with a yttrium distribution of 86.2% and a concentration of 8.4g / L, a high neodymium rare earth solution with a neodymium distribution of 80.6% and a concentration of 7.7g / L, and a high lanthanum rare earth solution with a lanthanum distribution of more than 87.4% and a concentration of 8.1g / L.

[0024] Example 2

[0025] The ionic rare earth leaching tailings are loaded into a pipeline, and then the ionic rare earth ore (medium yttrium-rich europium type) is loaded into the pipeline (the inner diameter of the pipeline is 5 cm), and the loading mass ratio of the ionic rare earth leaching tailings to the ionic rare earth ore is controlled to be 0.8:1; the aspect ratio of the pipeline is 2000, and the overall loading height should be 1500 times the diameter of the pipeline; the negative pressure at the pipeline outlet is controlled to be 10Kpa, and then 0.6mol / L ammonium sulfate leaching agent is added to the pipeline inlet for leaching, and 0.005mol / L sulfosalicylic acid is added to the leaching agent. The rare earth leachate at the outlet is collected in sections to obtain a high yttrium rare earth solution with a yttrium distribution of 84.3% and a concentration of 6.2g / L, a high neodymium rare earth solution with a neodymium distribution of 76.1% and a concentration of 5.1g / L, and a high lanthanum rare earth solution with a lanthanum distribution of more than 82.4% and a concentration of 6.1g / L.

[0026] Example 3

[0027] The ionic rare earth leaching tailings were loaded into the pipeline, and then the ionic rare earth ore (medium yttrium-rich europium type) was loaded into the pipeline (the inner diameter of the pipeline was 5 cm), and the loading mass ratio of the ionic rare earth leaching tailings and the ionic rare earth ore was controlled to be 2:1; the aspect ratio of the pipeline was 5000, and the overall loading height should be 4500 times the diameter of the pipeline; the negative pressure at the pipeline outlet was controlled to be 50Kpa, and then 0.2mol / L ammonium sulfate and 0.3mol / L ammonium sulfate were added at the pipeline inlet. 0.01 mol / L magnesium sulfate is used as a leaching agent for leaching, and 0.01 mol / L citric acid and 0.01 mol / L oxalic acid are respectively added to the leaching agent. The rare earth leachate at the outlet is collected in sections to obtain a high yttrium rare earth solution with a yttrium distribution of 91.2% and a concentration of 7.3 g / L, a high neodymium rare earth solution with a neodymium distribution of 85.6% and a concentration of 6.8 g / L, and a high lanthanum rare earth solution with a lanthanum distribution of more than 93.1% and a concentration of 7.6 g / L.

[0028] Example 4

[0029] The ionic rare earth leaching tailings are loaded into a pipeline, and then the ionic rare earth ore (medium yttrium-rich europium type) is loaded into the pipeline (the inner diameter of the pipeline is 5 cm), and the loading mass ratio of the ionic rare earth leaching tailings to the ionic rare earth ore is controlled to be 1.5:1; the aspect ratio of the pipeline is 4000, and the overall loading height should be 3000 times the diameter of the pipeline; the negative pressure at the pipeline outlet is controlled to be 40Kpa, and then 0.55mol / L ammonium sulfate leaching agent is added at the pipeline inlet for leaching, and the rare earth leachate at the outlet is collected in sections, so as to obtain a high yttrium rare earth solution with a yttrium distribution of 89.7% and a concentration of 7.8g / L, a high neodymium rare earth solution with a neodymium distribution of 83.1% and a concentration of 5.5g / L, and a high lanthanum rare earth solution with a lanthanum distribution of more than 91.1% and a concentration of 6.3g / L.

Claims

1. A pipeline leaching method for ionic rare earth ores, characterized in that: First, ionic rare earth leaching tailings are loaded into a pipeline, and then ionic rare earth ore is loaded into the pipeline, and the loading mass ratio of the ionic rare earth leaching tailings to the ionic rare earth ore is controlled to be ≥0.8:1; the aspect ratio of the pipeline is 2000-5000, and the overall loading height should be more than 1500 times the diameter of the pipeline; the pipeline outlet is controlled to be negative pressure, and then a leaching agent is added at the pipeline inlet to leach the ore, and the rare earth leachate at the outlet is collected in sections to obtain a high yttrium rare earth solution with a yttrium distribution of more than 80%, a high neodymium rare earth solution with a neodymium distribution of more than 70%, and a high lanthanum rare earth solution with a lanthanum distribution of more than 80%; and a water-soluble carboxylic acid compound is added to the leaching agent.

2. The method according to claim 1, characterized in that The leaching agent is a salt solution containing at least one of ammonium ions, magnesium ions, iron ions and aluminum ions, and its cation concentration is 0.3-0.6 mol / L.

3. The method according to claim 1 or 2, characterized in that: The concentration of the water-soluble carboxylic acid compound is 0.005-0.02 mol / L.

4. The method according to claim 1, characterized in that: The water-soluble carboxylic acid compound is at least one of sulfosalicylic acid, citric acid and oxalic acid.

5. The method according to claim 1, wherein the negative pressure at the pipeline outlet is controlled to be 10KPa-50KPa.