WO2016041436A1

WO2016041436A1 - Leaching agent and leaching method for leaching rare earth in ion-adsorbed rare earth ore

Info

Publication number: WO2016041436A1
Application number: PCT/CN2015/088300
Authority: WO
Inventors: 黄小卫; 冯宗玉; 王良士; 王猛; 崔大立; 肖燕飞; 董金诗; 赵娜; 黄莉
Original assignee: 有研稀土新材料股份有限公司
Priority date: 2014-09-19
Filing date: 2015-08-27
Publication date: 2016-03-24
Also published as: BR112017000461B1; CN105483373B; MY184299A; CN105483373A; BR112017000461A2; CL2016003303A1

Abstract

A leaching agent and leaching method for leaching a rare earth element in an ion-adsorbed rare earth ore; the leaching agent is an aqueous solution comprising reducing ions. The present invention uses the aqueous solution comprising the reducing ions as a leaching agent to leach an ion-adsorbed rare earth ore, and leaches an ionic phase rare earth element from a rare earth ore via an ion exchange method. In addition, the present invention utilizes the reducing action of the reducing ions so as to enable high-valence rare earth ions in a colloidal phase and a mineral phase to undergo a reduction reaction, such that low-valence ions leach out, thus improving a leaching rate of a rare earth element in the ion-adsorbed rare earth ore.

Description

Leaching agent and leaching method for leaching rare earth in rare earth ore

Technical field

The invention relates to the field of rare earth extraction and recovery, and in particular to a leaching agent and a leaching method for leaching rare earth in an ion-adsorbing rare earth ore.

Background technique

Ion-adsorbed rare earth ore is rich in medium and heavy rare earth elements and has extremely high economic value. It is a valuable strategic mineral resource in China and is widely distributed in seven southern provinces such as Jiangxi, Guangdong, Guangxi, Hunan, Fujian, Yunnan and Zhejiang. The rare earth elements in the ion-adsorbed rare earth ore are divided into four types, namely, water-soluble phase rare earth, ionic phase rare earth, colloidal phase rare earth, and mineral phase rare earth. The rare earth in the water-soluble phase accounts for less than one ten-thousandth of the total rare earth, which can be neglected; the ionic phase rare earth accounts for more than 80% of the total rare earth, and is mainly adsorbed to kaolin, feldspar, mica, etc. in the form of hydrated ions or hydroxyhydrated ions. The surface of clay minerals. The colloidal phase rare earth is mainly deposited on the mineral by water-insoluble oxide or hydroxide colloid (Ce(OH) ₄ is the main body), accounting for about 5% of the total rare earth; in the mineral phase, it is rare earth mineral such as Fangqi It exists in the form of ore, bastnasite ore, monazite, etc., accounting for 10%-15% of the total amount of rare earth.

The rare earth ore in the ion-adsorbed rare earth ore has a low grade, generally 0.05% to 0.3%, and the ore has a small particle size. The conventional physical beneficiation method cannot enrich the rare earth into a concentrate. However, the ionic phase rare earth adsorbed in the clay mineral can be exchange-desorbed when it encounters chemically active cations (Na ⁺ , NH ₄ ⁺ , Mg ²⁺ , Ca ^{2+ ,} etc.). According to this feature, Chinese scientists and technicians have used sodium chloride and ammonium sulfate as leaching agents to extract ionic phase rare earth. The leaching efficiency and selectivity of ammonium sulfate are obviously better than that of sodium chloride, which is beneficial to the extraction of rare earth ions in the leaching solution. Therefore, ammonium sulfate is generally used as a rare earth leaching agent in the industry. However, in general, the leaching agent for the ion-adsorbed rare earth ore can only leaching the rare earth elements in the ionic phase, and the leaching effect is poor for the rare earth of the colloidal phase and the mineral phase, resulting in poor leaching effect. Loss of rare earth resources. Therefore, the ammonium sulfate leaching ion-adsorbed rare earth ore only recovers more than 80% of the ionic phase rare earth in the ore; and the 1t rare earth concentrate (according to REO) consumes 7-9 tons of ammonium sulfate, and a large amount of ammonia nitrogen enters the soil and In the groundwater, the ammonia nitrogen in the water system of the mining area is seriously exceeded, and the water body is eutrophicated, which has a serious impact on the ecological environment.

Chinese Patent 201010128302.9 "A method for recovering rare earth from ionic rare earth ore" in which at least one of magnesium sulfate, magnesium chloride and calcium chloride replaces most or all of ammonium sulfate, ammonium chloride or sodium chloride as leaching Agent for leaching ion-adsorbed rare earth ore; Chinese Patent 201310199034.3 "An ion-adsorbing rare earth extraction method" using magnesium sulfate, or magnesium sulfate and/or iron sulfate, or magnesium sulfate and/or aluminum sulfate as a main component of The aqueous solution is used as a leaching agent to leach the ion-adsorbed rare earth ore; Chinese Patent 201310424572.8 "Ion-adsorption rare earth mineral non-ammonium salt leaching rare earth process" adopts any determination of the ratio of calcium salt, magnesium salt and sodium salt, and The determined ratio is prepared to form a composite salt as a leaching agent for leaching ion-adsorbing rare earth ore; Chinese patent 201310481335.5 "a weathering shell leaching type rare earth ore leaching agent and a method for extracting rare earth" adopts ammonium citrate and citric acid Any one or any combination of sodium, potassium citrate and magnesium citrate is used as a leaching agent to leach the ion-adsorbed rare earth ore. Although the leaching agent used in the above patents all reduces or eliminates the problem of ammonia nitrogen leaching by ammonium sulphate leaching, the leaching of rare earth elements in the colloidal phase and the mineral phase has not been achieved. The Chinese patent 201310594438.2 "a method for improving the leaching rate of ion-type rare earth and the safety of tailings" and the literature "Study on the rare earth extraction of colloidal phase in black weathering of a rare earth mineral in southwest" adopts strong non-reducing ions. The acidic solution leaches the rare earth leaching rare earth in the ion-adsorbed rare earth ore. The leaching efficiency is low, and the leaching acidity is high, and a large amount of minerals in the soil are leached, resulting in a substantial increase in the impurity content in the leaching solution.

How to recover the ionic phase in the ion-adsorbed rare earth ore, and extract the rare earth in some of the colloidal phase and the mineral phase to further improve the rare earth leaching rate has become a hot research direction.

Summary of the invention

The invention aims to provide a leaching agent and a leaching method for leaching rare earth ions in an ion-adsorbing rare earth ore to solve the problem of colloidal phase and mineral phase rare earth in the ion absorbing rare earth ore leaching process in the prior art. The problem of being fully immersed.

In order to achieve the above object, according to an aspect of the invention, a leaching agent for leaching rare earth in an ion-adsorbing rare earth ore is provided, the leaching agent being an aqueous solution containing a reducing ion.

Further, the reducing ion is one or more of a ferrous ion, a divalent manganese ion, a sulfite ion, and a hydrogen sulfite ion; preferably, the reducing ion is a ferrous ion.

Further, the leachant further includes one or more of magnesium ions, calcium ions, potassium ions, and ammonium ions, and preferably includes magnesium ions and/or calcium ions.

Further, in the leaching agent, the concentration of the cation other than the hydrogen ion is 0.05 to 1.00 mol/L, preferably 0.10 to 0.50 mol/L.

Further, in the leaching agent, the concentration of the reducing ions is 0.01 to 0.30 mol/L, preferably 0.01 to 0.05 mol/L.

Further, the pH of the leachant is from 1.0 to 5.0, preferably from 1.5 to 3.5.

Further, the leaching agent includes, in mole percent, from 1 to 30% of ferrous ions, from 1 to 95% of magnesium ions, from 1 to 50% of calcium ions, and from 0 to cations other than hydrogen ions. ~15% potassium ion and 0-30% ammonium ion.

According to another aspect of the present invention, there is provided a method for leaching rare earth in an ion-adsorbing rare earth ore by leaching a rare earth in an ion-adsorbing rare earth ore using the above-mentioned leaching agent. Further, the above method comprises the steps of: S1, using an ion-adsorbing rare earth ore as a raw material, and determining a leaching agent to be configured according to a deficiency of ferrous ions, magnesium ions, calcium ions, potassium ions and ammonium ions in the raw material; The molar percentage of each ion is arranged, and the leaching agent is disposed; S2, the ion-adsorbing rare earth ore is leached by using a leaching agent to obtain a rare earth leaching solution and a rare earth tailings.

Further, after the rare earth leaching solution is obtained, the rare earth leaching solution is subjected to impurity removal, and then the rare earth leaching solution after the impurity removal is subjected to rare earth precipitation or extraction and enrichment recovery to obtain a rare earth rich material and a residual liquid.

Further, after the remaining liquid is obtained, the remaining liquid is prepared according to the concentration of each ion in the leaching agent, and used again as a leaching agent.

The present invention employs an aqueous solution containing a reducing ion as a leaching agent for leaching rare earth ions in rare earth ore. The ion-adsorbed rare earth ore is leached by the leaching agent, and the ionic phase rare earth in the rare earth ore can be extracted by ion exchange. At the same time, it is also possible to use a reduction of reducing ions to cause a redox reaction of a high-valent rare earth ion (such as tetravalent cerium) in a colloidal phase and a mineral phase to form a low-valent ion (such as trivalent cerium) to enter the leaching solution. . At the same time, the leaching rate of the rare earth in the ion-adsorbed rare earth ore can be improved by leaching the ionic phase, the partially colloidal phase and the rare earth in the mineral phase in the ion-adsorbed rare earth ore.

detailed description

It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. The invention will be described in detail below with reference to the embodiments.

As described in the background section, when the existing leaching agent is used to leach the rare earth in the ion-adsorbed rare earth ore, the rare earth and mineral phase rare earths of the colloidal phase are not sufficiently extracted. In order to solve this problem, the inventors of the present invention provide a leaching agent for leaching rare earth in an ion-adsorbing rare earth ore, the leaching agent being an aqueous solution containing reducing ions.

The above-mentioned leaching agent provided by the present invention employs an aqueous solution containing reducing ions. The ion-adsorbing rare earth ore is leached by using an aqueous solution containing a reducing ion as a leaching agent, and the ionic phase rare earth in the rare earth ore can be extracted by ion exchange. At the same time, it is also possible to use the reduction of reducing ions to make the colloidal phase and the mineral phase The high-valent rare earth ions (such as tetravalent cerium) undergo a reduction reaction to form a low-valent ion (such as trivalent cerium) to enter the leaching solution. This can increase the leaching rate of rare earth in the ion-adsorbed rare earth ore.

In the above leaching agent provided by the present invention, conventional reducing ions such as ferrous ions, divalent manganese ions, divalent tin ions, divalent vanadium ions, trivalent vanadium ions, sulfite ions, sulfurous acid are used. Hydrogen ions, sulfur ions, iodide ions, sulphide ions or thiosulfate ions can reduce the tetrabasic cerium in the rare earth ore and the tetravalent cerium in the mineral phase to trivalent cerium during the leaching process. It is allowed to enter the rare earth leachate. In a preferred embodiment, the reducing ion is one or more of a ferrous ion, a divalent manganese ion, a sulfite ion, and a hydrogen sulfite ion. Compared with other reducing ions, the above-mentioned several reducing ions used in the present invention are beneficial for improving the sufficient reaction of the ion-adsorbed rare earth colloidal phase and the rare earth ions in the mineral phase. Thereby, the leaching rate of the rare earth in the ion-adsorbed rare earth ore can be further improved.

More preferably, the above reducing ion is a ferrous ion. The reduction performance of ferrous ions is strong, the source is wide, and the price is cheap. At the same time, iron is a nutrient for soil and vegetation. Specifically, ferrous iron is an essential element for plant chlorophyll synthesis, participates in oxidation reactions and electron transport in plants. The use of ferrous ions as reducing ions in the leaching agent can not only improve the leaching rate of rare earth in the ion-adsorbed rare earth ore, but also help to prevent the external elements from causing damage to the soil in the environment where the original rare earth ore is located, and maintain the ecological balance. Therefore, the use of ferrous ions as a reducing ion in the leaching agent has both a rare earth leaching function and environmental performance.

In the above-mentioned leaching agent provided by the present invention, as long as the reducing ions are contained, the leaching rate of the rare earth in the ion-adsorbing rare earth ore can be improved. In a preferred embodiment, the leaching agent further comprises one or more of magnesium ions, calcium ions, potassium ions, and ammonium ions, which are all nutrients required for the soil. Specifically, magnesium ions are part of plant chlorophyll and phytochemicals, participate in carbon and nitrogen metabolism in crops, and promote the synthesis of carbon, fat and protein; calcium ions contribute to the stability of plant cell membranes, inhibit fungal attack, slow down aging and Decay is also a catalyst for certain enzymes; potassium ions promote the activation of enzymes in plants, promote sugar metabolism, promote protein synthesis, and participate in cell osmotic regulation; nitrogen in ammonium ions is an important group of proteins, nucleic acids, chlorophyll and many enzymes. Minute. In addition, when the rare earth leaching of the ion-adsorbing rare earth ore is carried out, these ions have high ion exchange performance, which is favorable for further increasing the leaching rate of the rare earth. More preferably, the above leaching agent comprises magnesium ions and/or calcium ions. Compared with other ions, calcium ions and magnesium ions have higher exchange leaching ability, which can reduce the molar concentration of cations in the leaching agent, and the calcium and magnesium ions have less environmental pollution. In addition, calcium ions and magnesium ions have a wide source and low price, and are more suitable for large-scale leaching of rare earths. At the same time, the use of calcium and magnesium ions can also reduce or eliminate the problem of ammonia nitrogen pollution caused by industrial ammonium leaching.

In the above-mentioned leaching agent provided by the present invention, the concentration of the cation other than the hydrogen ion is preferably 0.05 to 1.00 mol/L, and more preferably 0.10 to 0.50 mol/L. The higher the cation concentration, the more favorable the rare earth leaching rate Increase, but too high a concentration will increase the cost, while having an impact on the environment. Considering the factors of both aspects, it is appropriate to control the concentration of the cation in the above range.

Among the above-mentioned leaching agents provided by the present invention, those skilled in the art can select the specific concentration of each ion. In a preferred embodiment, the concentration of the reducing ions in the leaching agent is 0.01 to 0.30 mol/L, preferably 0.01 to 0.05 mol/L. The higher the concentration of reducing ions, the more favorable the reduction leaching of the colloidal phase and the rare earth of the mineral phase. However, excessively high concentrations have problems such as high energy consumption, increased load, and increased cost in subsequent processes, and have an impact on the environment. Controlling the reducing ions in the above concentration range can promote the leaching rate of the rare earth in the colloidal phase and the mineral phase in the ion-adsorbing rare earth ore. At the same time, it is also beneficial to prevent the high cost and the ecological balance caused by the introduction of excessive ions.

In the above-mentioned leaching agent provided by the present invention, the rare earth leaching rate in the ion-adsorbing rare earth ore can be effectively improved as long as the reducing ions and non-reducing ions such as magnesium ions and calcium ions are contained. In a preferred embodiment, the leachant has a pH of from 1.0 to 5.0, preferably from 1.5 to 3.5. The lower the pH of the leachant, the higher the rare earth leaching rate of the colloidal phase and the mineral phase, but the peracid leaching agent adversely affects the soil, and the leaching of the impurity aluminum is greatly increased. Under this acidic condition, the reducing ions have high stability and reducing ability. At the same time, the magnesium ion and the calcium ion have the effect of suppressing the leaching of the impurity aluminum when the ion-adsorbing rare earth ore is leached under the acidic condition. In addition, controlling the acidity of the leachant to the above range is also advantageous for preventing excessive acidity from damaging the soil and causing pH imbalance of the soil.

Those skilled in the art can select the specific amount of relationship between the ions in accordance with the teachings of the present invention. In a preferred embodiment, the leaching agent includes 1 to 30% of ferrous ions, 1 to 95% of magnesium ions, and 1 to 1% of the cations other than hydrogen ions. 50% calcium ion, 0-15% potassium ion and 0-30% ammonium ion. Controlling the amount of each ion in the leachant to the above range is advantageous for further increasing the leaching rate of the rare earth in the ion-adsorbed rare earth ore. At the same time, it can also match the lack of various trace elements in the soil, so that the leachant meets the ecological requirements.

It should be noted that in the process of arranging the above-mentioned leaching agent, it is only necessary to add the soluble salt of the target ion to the water. For example, ferrous ions can be introduced by adding ferrous sulfate, ferrous chloride, and ferrous nitrate; divalent manganese ions can be added by adding manganese sulfate, manganese chloride, manganese nitrate, etc.; sulfite ions can pass Introduced by adding ammonium sulfite, magnesium sulfite, etc.; bisulfite ions can be introduced by adding ammonium hydrogen sulfite, magnesium hydrogen sulfite, potassium hydrogen sulfite, calcium hydrogen sulfite, etc.; Magnesium, calcium, potassium and ammonium ions are introduced by means of calcium chloride, potassium sulfate or ammonium sulfate. A person skilled in the art can select a specific soluble salt by itself, and details are not described herein. In view of the small effect of sulfate on the soil, it is preferred to introduce each cation in the form of a soluble sulfate.

Further, according to another aspect of the present invention, there is provided a method of leaching rare earth in an ion-adsorbing rare earth ore by leaching a rare earth in an ion-adsorbing rare earth ore using the above-mentioned leaching agent.

In the above method for extracting rare earth in an ion-adsorbing rare earth ore provided by the present invention, the leaching agent used contains a reducing ion. The ion-adsorbing rare earth ore is leached by using an aqueous solution containing a reducing ion as a leaching agent, and the ionic phase rare earth in the rare earth ore can be extracted by ion exchange. At the same time, it is also possible to use a reduction of reducing ions to cause a redox reaction of a high-valent rare earth ion (such as tetravalent cerium) in a colloidal phase and a mineral phase to form a low-valent ion (such as trivalent cerium) to enter the leaching solution. . This can increase the leaching rate of rare earth in the ion-adsorbed rare earth ore.

In the above method provided by the present invention, the specific leaching step may employ a process which is conventionally used by those skilled in the art in leaching rare earth ore. In a preferred embodiment, the method comprises the following steps: S1, using ion-adsorbing rare earth ore as raw material, and determining the desire according to the lack of ferrous ions, magnesium ions, calcium ions, potassium ions and ammonium ions in the raw materials. The leaching agent is disposed in the leaching agent and the leaching agent is disposed; S2, the ion absorbing rare earth ore is leached by the leaching agent to obtain the rare earth leaching solution and the rare earth tailings. Before the step of leaching the rare earth ore, the leaching agent is configured by examining the deficiency of each ion (the nutrient element required for vegetation growth) in the raw material (taken from the rare earth mine). This is beneficial to introduce nutrients suitable for vegetation growth into the mine soil while fully leaching rare earth elements in the rare earth ore, and to prevent excessive applied ions from destroying the ecological balance. In the above step of leaching the ion-adsorbing rare earth ore by using a leaching agent, it is preferred to carry out the leaching by means of in-situ immersion or heap leaching.

In the above method, after the rare earth leaching solution is obtained, the rare earth element can be recovered from the leaching solution according to a conventional enrichment method. In a preferred embodiment, after the rare earth leaching solution is obtained, the rare earth leaching solution is subjected to impurity removal, and then the rare earth leaching solution after the impurity removal is subjected to rare earth precipitation or extraction and enrichment recovery to obtain a rare earth rich material and a residual liquid. The above step of removing the rare earth leaching solution may be carried out by a method of removing impurities conventionally used by those skilled in the art. The step of subjecting the rare earth element in the rare earth leaching solution to precipitation treatment or extraction and enrichment recovery may also be carried out by a method conventionally used by those skilled in the art. I will not repeat them here.

In a preferred embodiment, after the remaining liquid is obtained, the remaining liquid is prepared according to the concentration of each ion in the leaching agent, and is reused as a leaching agent. Recycling and recycling the remaining liquid is conducive to saving energy and reducing the cost of leaching.

In a preferred embodiment, after obtaining the rare earth tailings, the rare earth tailings are washed with water to obtain a water washing liquid and a washed tailings; according to the concentration of each ion of the leaching agent, the water washing liquid is prepared to serve as a leaching agent again. use. The rare earth tailings are washed with water, and the obtained water washing liquid is further recycled, which can further reduce the leaching cost of the rare earth.

In the above method provided by the present invention, according to the deficiency of nutrient elements (ferrous iron, calcium, magnesium, potassium, ammonium) of the ion-adsorbing rare earth mine and the leaching ability of each cation to the rare earth, the appropriate ratio is prepared. Get The salt solution containing the nutrient deficiency is used as a leaching agent to extract the rare earth and supplement the nutrients required by the mine, which is beneficial to the tailings repair. After the leaching, the tailings are treated with the top water, and the nutrient content can be Satisfy the growth of plants, and replace most of the ammonium sulfate with ferrous, magnesium, calcium and potassium in the leachant, reduce or even eliminate the ammonia nitrogen pollution, and realize the eco-friendly leaching of the ion-adsorbed rare earth mine.

The invention is further described in detail below with reference to the specific embodiments, which are not to be construed as limiting the scope of the invention.

In Examples 1 to 20 and Comparative Examples 1 and 2, different leaching agents were used to leach the ion-adsorbed rare earth ore, and the specific leaching method was column immersion.

Leaching process: the ion leaching rare earth ore is subjected to column leaching by using the configured leaching agent until the rare earth concentration in the leaching column effluent is less than 0.1 g/L, the leaching is stopped, and the rare earth leaching solution and the rare earth tailings are obtained. Among them, the rare earth leaching solution was tested by ICP method, and the concentration of each rare earth element was obtained to calculate the rare earth leaching rate and the cerium compounding fraction.

The ionic composition, concentration, and total concentration of cations other than hydrogen ions in the leaching agent in different examples and comparative examples are shown in Table 1:

Table 1

Remarks: The concentration shown in the reducing ion source in Table 1 is the concentration of reducing ions. As in Example 5, 0.05 mol/L ammonium sulfite refers to a sulfite ion concentration of 0.05 mol/L. The ammonium ion concentration corresponding to ammonium is 0.1 mol/L. The concentration shown in other ion source items is the cation concentration. For example, 0.2 mol/L ammonium sulfate in Comparative Example 2 means that the ammonium ion concentration is 0.2 mol/L.

The ion-adsorbing rare earth ore parameters and the leaching conditions of rare earths in the respective examples are shown in Table 2:

Table 2

Example 21 (using in situ leaching)

In an ion-type rare earth mine in the south, the thickness of the rare earth ore layer is 7 meters, the average grade of rare earth is 0.11%, and the proportion of lanthanum is 0.63%. The rare earth reserves of the ore body are 54 tons, and the in-situ leaching process is used to complete the processes of injecting liquid wells, collecting holes and laying pipelines on the surface of the ore body. The effective ferrous iron, available calcium, available magnesium, available potassium, and available ammonia (sum of ammonium and nitrate nitrogen) in the ore soil are 3.1 mg/kg, 153 mg/kg, 32 mg/kg, 57 mg/ Kg, 43 mg/kg. According to the indicator of the effective content of each element in the soil, a mixed leachant containing ferrous sulfate, magnesium sulfate, calcium chloride, potassium sulfate and ammonium sulfate is prepared 8000m ³ under the premise of ensuring that the rare earth can be effectively leached. The ferrous ion concentration is 0.03 mol/L, the magnesium ion concentration is 0.20 mol/L, the calcium ion concentration is 0.01 mol/L, the potassium ion concentration is 0.02 mol/L, and the ammonium ion concentration is 0.04 mol/L. The leaching agent is injected into the leaching agent 350m ³ every day, and the rare earth concentration in the leaching solution is less than 0.3g/L. All the pumps are continuously immersed in the leaching. After the concentration of the leaching solution is more than 0.3g/L, the liquid is collected and the rare earth content in the leaching solution to be collected is collected. When approaching the reserve, change the water to rinse the liquid.

The collected leachate is separated by magnesium oxide, P507 and P204 are extracted by stepwise extraction to obtain rare earth enrichment and residual liquid, and the remaining liquid is added with ferrous sulfate, magnesium sulfate and chlorine according to the concentration of each ion in the leachant. Calcium, potassium sulfate, ammonium sulfate are blended and returned for leaching. The rare earth enrichment contained 52.2 tREO, the average distribution of rhodium was 5.62%, and the rare earth recovery rate was 96.7%. The effective ferrous iron, available calcium, available magnesium, available potassium and available ammonia (sum of ammonium and nitrate nitrogen) in the mine tailings soil after washing are 5.1mg/kg, 412mg/kg, 196mg/ Kg, 98mg/kg and 153mg/kg provide supplemental nutrients in the soil, and the tailings are easy to repair, achieving eco-friendly leaching of rare earths.

Example 22 (using a heap leaching method)

200 tons of ionic rare earth ore (Rare Earth grade 0.15% REO, 铈 distribution 2.04%) were piled up, compacted, and the bottom was separated by plastic cloth. The effective ferrous iron, available calcium, available magnesium, available potassium, and available ammonia (sum of ammonium nitrogen and nitrate nitrogen) in the ore are 2.6mg/kg, 143mg/kg, 54mg/kg, 42mg/kg, respectively. With 31mg/kg. According to the abundance index of the effective content of each element in the soil, under the premise of ensuring that the rare earth can be effectively leached, a mixed leaching agent containing 150 g ^{3 of} ferrous sulfate, magnesium sulfate, calcium chloride, potassium sulfate and ammonium sulfate is prepared, wherein The ferrous ion concentration is 0.04 mol/L, the magnesium ion concentration is 0.20 mol/L, the calcium ion concentration is 0.01 mol/L, the potassium ion concentration is 0.05 mol/L, and the ammonium ion concentration is 0.10 mol/L. The mixed leaching agent 150 m ³ was slowly sprayed onto the rare earth ore and finally rinsed with 20 m ^{3 of} water to obtain a washed tailings and leachate. The rare earth leaching solution was 143 m ³ , the REO content was 2.09 g/L, the rare earth leaching rate was 98.2%, and the cerium distribution in the leaching solution was 6.92%. After the leachate is removed and precipitated, the mixed rare earth carbonate product and the remaining liquid are obtained, and the remaining liquid is added with ferrous sulfate, magnesium sulfate, calcium chloride, potassium sulfate and ammonium sulfate, and is returned for use in leaching. The effective ferrous iron, available calcium, available magnesium, available potassium, and available ammonia (sum of ammonium and nitrate nitrogen) in rare earth tailings are 6.4mg/kg, 384mg/kg, 184mg/kg, 127mg, respectively. /kg and 176mg/kg provide supplemental nutrients in the soil, and the tailings are easy to repair, achieving eco-friendly leaching of rare earths.

From the above data, it can be seen that the above embodiments of the present invention achieve the following technical effects:

When the rare earth in the ion-adsorbed rare earth ore is leached by a leaching agent containing a reducing ion, the rare earth leaching rate and the cerium component can be improved. In particular, when ferrous ions are used as reducing ions, they have a higher rare earth leaching rate and a ruthenium complex. At the same time, the above-mentioned leaching agent provided by the invention can also bring the necessary nutrient elements to the mine soil, and is a high leaching rate and environment-friendly rare earth leaching agent.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A leaching agent for leaching rare earth in an ion-adsorbing rare earth ore, characterized in that the leaching agent is an aqueous solution containing reducing ions.
The leachant according to claim 1, wherein the reducing ion is one or more of a ferrous ion, a divalent manganese ion, a sulfite ion, and a hydrogen sulfite ion; The reducing ion is a ferrous ion.
The leaching agent according to claim 1, wherein the leaching agent further comprises one or more of magnesium ions, calcium ions, potassium ions, ammonium ions, preferably including magnesium ions and/or calcium. ion.
The leaching agent according to any one of claims 1 to 3, wherein a cation concentration other than hydrogen ions in the leaching agent is 0.05 to 1.00 mol/L, preferably 0.10 to 0.50 mol/ L.
The leaching agent according to any one of claims 1 to 4, wherein a concentration of the reducing ion in the leaching agent is 0.01 to 0.30 mol/L, preferably 0.01 to 0.05 mol/L. .
The leaching agent according to any one of claims 1 to 5, wherein the leaching agent has a pH of 1.0 to 5.0, preferably 1.5 to 3.5.
The leaching agent according to claim 1, wherein the leaching agent comprises, in a molar percentage, 1 to 30% of ferrous ions, and 1 to 95, with respect to a cation other than hydrogen ions. % magnesium ion, 1 to 50% calcium ion, 0 to 15% potassium ion, and 0 to 30% ammonium ion.
A method for leaching rare earth in an ion-adsorbing rare earth ore, characterized in that the rare earth in the ion-adsorbing rare earth ore is leached by using the extracting agent according to any one of claims 1 to 7.
The method of claim 8 including the steps of:

S1, using an ion-adsorbed rare earth ore as a raw material, and determining a mole of each ion in the leaching agent to be disposed according to a deficiency of ferrous ions, magnesium ions, calcium ions, potassium ions, and ammonium ions in the raw material Percentage and configuration of the leachant;

S2: immersing the ion-adsorbing rare earth ore with the leaching agent to obtain a rare earth leaching solution and a rare earth tailings.
The method according to claim 9, wherein after the rare earth leaching solution is obtained, the rare earth leaching solution is subjected to impurity removal, and then the rare earth leaching solution after the impurity removal is subjected to rare earth precipitation or extraction and enrichment recovery to obtain a rare earth. Enrichment and residual liquid.
The method according to claim 10, wherein after the residual liquid is obtained, the remaining liquid is formulated according to the concentration of each ion in the leaching agent to be used again as the leaching agent.
The method according to any one of claims 8 to 11, wherein the ion-adsorbing rare earth ore is leached by one or more methods of in-situ immersion, heap leaching, continuous immersion or continuous stirring immersion. Rare earth.