阅读说明：本技术 一种从深海沉积物中提取稀土元素的方法 (Method for extracting rare earth elements from deep sea sediments ) 是由 潘炳 任国兴 王祥 麦笑宇 肖松文 钟志刚 于 2020-06-30 设计创作，主要内容包括：本发明公开了一种从深海沉积物中提取稀土元素的方法,具体包括以下步骤：准备浸出装置,浸出装置包括浸出液出口、连接外部与反应槽的入料管道以及内部带有搅拌组件的反应槽；将酸液、絮凝剂和深海沉积物通过入料管道加入浸出装置中,打开搅拌组件,经浸出装置搅拌浸出后,由浸出液出口收集浸出液。本发明可同时实现沉积物中稀土元素的浸出和浸出液与浸出渣的分离,所得到的浸出渣含水率低于40％；本发明公开的从深海沉积物中提取稀土元素的方法无需对开采出来的高含水率深海富稀土沉积物烘干处理,可直接配酸进行浸出反应,可降低成本,并有效提高稀土元素的浸出率。(The invention discloses a method for extracting rare earth elements from deep sea sediments, which specifically comprises the following steps: preparing a leaching device, wherein the leaching device comprises a leaching liquid outlet, a feeding pipeline for connecting the outside with the reaction tank, and the reaction tank with a stirring component inside; adding acid liquor, flocculating agent and deep sea sediment into the leaching device through a feeding pipeline, opening the stirring assembly, stirring and leaching by the leaching device, and collecting the leaching solution through a leaching solution outlet. The invention can simultaneously realize the leaching of rare earth elements in the sediment and the separation of the leaching solution and the leaching slag, and the water content of the obtained leaching slag is lower than 40 percent; the method for extracting the rare earth elements from the deep sea sediments disclosed by the invention does not need to dry the exploited deep sea rare earth-rich sediments with high water content, can directly prepare acid for leaching reaction, can reduce the cost and effectively improve the leaching rate of the rare earth elements.)

1. A method for extracting rare earth elements from deep sea sediments is characterized in that a leaching device used in the method comprises a leachate outlet (9), a reaction tank (6) arranged inside the leaching device and a feeding pipeline (5) connected with the reaction tank (6) from the outside, wherein a stirring assembly is arranged in the reaction tank (6); the method specifically comprises the following steps: adding acid liquor, flocculating agent and the deep sea sediment into a leaching device through a feeding pipeline (5), opening the stirring component, stirring and leaching through the leaching device, and collecting leachate through a leachate outlet (9).

2. The method for extracting rare earth elements from deep sea sediments according to claim 1, wherein the acid solution is one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and citric acid.

3. The method for extracting rare earth elements from deep sea sediments according to claim 2, wherein the concentration of said acid liquor is between 0.05mol/L and 1.0 mol/L.

4. The method for extracting rare earth elements from deep sea sediments according to claim 1, wherein an additive is further added in the leaching device, and the additive is one or more of ammonium sulfate, ammonium chloride, aluminum sulfate, aluminum chloride and magnesium sulfate; the addition concentration of the additive is 0.5-4%.

5. The method for extracting rare earth elements from deep sea sediments of claim 1, wherein the concentration of said deep sea sediments is between 10% and 60%; the residence time of the deep sea sediment in the rare earth element leaching device is 30-2400 minutes.

6. The method for extracting rare earth elements from deep sea sediments according to claim 1, wherein the flocculating agent is negative polyacrylamide, positive polyacrylamide or neutral polyacrylamide; the addition concentration of the flocculant is 0.05-0.15 g/L.

7. The method for extracting rare earth elements from deep sea sediments according to any of the claims from 1 to 6, wherein the leaching plant also comprises a rake (2), a transmission assembly (7) and a casing (10) with a slag discharge (1) at the lowest bottom; the transmission assembly (7) is arranged outside the shell (10) and is connected with the rake rack (2); the rake rack (2) is arranged above the bottom of the shell (10) in parallel; the leachate outlet (9) is arranged at the top of the shell (10); the reaction tank (6) is arranged in the middle of the top of the shell (10), and a slurry outlet is formed in the bottom of the reaction tank (6).

8. Method for the extraction of rare earths from deep sea sediments according to any of the claims from 1 to 6, characterised in that said reaction tank (6) is provided, from top to bottom, with a first stirring assembly (3) and a second stirring assembly (4).

9. The process for extraction of rare earths from deep sea sediments according to claim 8, characterized in that said first stirring assembly (3) comprises a plurality of helical blades, said first stirring assembly (3) being arranged in a position close to the junction of said reaction tank (6) and said feeding duct (5).

10. Method for the extraction of rare earths from deep sea sediments according to claim 8, characterised in that said second stirrer assembly (4) comprises a set of blades arranged vertically in an annular arrangement, said second stirrer assembly (4) being arranged in proximity to said slurry outlet.

Technical Field

The invention belongs to the field of rare earth metallurgy, and particularly relates to a method for extracting rare earth elements from deep sea sediments.

Background

Rare earth is used as a non-renewable key strategic resource, is an indispensable element raw material in many industrial fields such as atomic energy, metallurgy, petroleum, aviation, aerospace, electronic information and the like, and is called industrial monosodium glutamate. However, due to the long-term and ultra-intensive exploitation and utilization, the reserve of rare earth mineral resources on land has been rapidly reduced, and the search for replaceable rare earth mineral resources has become a real problem to ensure the urgent rare earth supply in the future.

In recent years, exploration of a plurality of mineral resources shows that deep-sea sediments have abundant rare earth resources. According to the report of Japanese scientists, the highest content of rare earth elements in deep sea sediments in the major ocean can reach 0.66 percent, the content of heavy rare earth elements is 2 times of the abundance of ionic rare earth minerals in south China, and the total resource reserves far exceed the current land resource reserves, so the method has great development and utilization values. Therefore, a great deal of research work has been carried out on the development and utilization of rare earth resources in deep sea rare earth-rich sediments.

For example, chinese patent application CN 107557576a discloses a method for extracting rare earth from deep sea sediments, which adopts sulfuric acid or hydrochloric acid to directly acid-leach sediments, adjusts the pH of the obtained leachate by sodium carbonate, sodium hydroxide, magnesium oxide or lime, and purifies and removes impurities. The obtained purified liquid is separated and recovered with a solvent extraction method. Chinese patent application CN109234548A discloses a method for leaching and extracting rare earth from deep sea sediments by a sulfuric acid self-heating curing pool, which utilizes a large amount of sulfuric acid dilution heat and chemical reaction heat generated in the mixing process of the deep sea sediments and sulfuric acid to realize the extraction of the rare earth by the sulfuric acid self-heating curing with low energy consumption. After the heat preservation of the cured material in the leaching tank for a certain time, the rare earth enters the solution through spraying water or stirring leaching. The two methods do not consider the practical problems of extremely low rare earth grade and ultrahigh content of impurity elements in the sediment, and the direct acid leaching process has the defects of extremely high acid consumption, difficult subsequent leaching and purification of leachate due to the massive leaching of the impurity elements and basically no industrial application prospect.

Chinese patent application CN 107983529A discloses a method for extracting rare earth from deep sea sediment, which comprises the steps of firstly carrying out desliming pretreatment on the deep sea sediment, then carrying out ore grinding and flotation enrichment on the deslimed product, and leaching the obtained flotation rough concentrate by dilute acid to obtain heavy rare earth-enriched leaching solution and light rare earth-containing leaching residue; and scrubbing the leached slag and then carrying out flotation separation to obtain rare earth concentrate. Although the method obtains the rare earth concentrate with higher grade, the process is complex, and the total recovery rate of the rare earth in the whole process is only about 40 percent, and still needs to be further optimized.

Unlike traditional land mineral resources, deep sea sediments have the following characteristics: (1) the water content is extremely high and reaches more than 70 percent, the smelting is not suitable for drying, otherwise, the energy consumption is extremely high; (2) the granularity is extremely fine, the silicon-aluminum content is high, and the leached pulp is difficult to separate through a traditional filtering device after the conventional acid leaching; (3) due to long-term action with seawater, the chloride salt content is extremely high, which causes difficulty in subsequent purification and impurity removal. Aiming at the problems in the prior art and combining the characteristics of deep sea sediment resources, the method for efficiently and economically extracting the rare earth from the deep sea rare earth-rich sediment is provided.

Disclosure of Invention

The invention aims to solve the technical problems that the defects and shortcomings in the background technology are overcome, and the method for extracting the rare earth elements from the deep sea sediments is provided, the leaching of the rare earth elements in the sediments and the separation of the leaching solution and the leaching residues can be realized simultaneously, and the water content of the obtained leaching residues is lower than 40%; the method does not need to dry the exploited deep sea rare earth-rich sediment with high water content, can directly prepare acid for leaching reaction, can reduce the cost and effectively improve the leaching rate of rare earth elements.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a method for extracting rare earth elements from deep sea sediments uses a leaching device which comprises a leaching liquid outlet, a reaction tank arranged inside the leaching device and a feeding pipeline connecting the outside with the reaction tank, wherein a stirring assembly is arranged in the reaction tank; the method specifically comprises the following steps: adding acid liquor, flocculating agent and the deep sea sediment into a leaching device through a feeding pipeline, opening the stirring assembly, stirring and leaching by the leaching device, and collecting leachate through a leachate outlet.

The method specifically comprises the following steps: preparing a leaching device, wherein the leaching device comprises a leaching liquid outlet, a feeding pipeline for connecting the outside with the reaction tank, and the reaction tank with a stirring component inside; adding acid liquor, flocculating agent and the deep sea sediment into a leaching device through a feeding pipeline, opening the stirring assembly, stirring and leaching by the leaching device, and collecting leachate from a leachate outlet.

Preferably, the acid solution is one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and citric acid; as a further preference, the acid solution is sulfuric acid; the reason for selecting sulfuric acid as the acid solution is that sulfuric acid has little environmental pollution, is not easy to decompose and has low price.

Preferably, the concentration of the acid solution is 0.05mol/L to 1.0mol/L, and more preferably, the concentration of the acid solution is 0.06mol/L to 0.80 mol/L. The acid liquor with the concentration has the best leaching effect on rare earth metals in deep sea sediments, and excessive concentration can cause massive leaching of impurity ions, is not beneficial to the purity of the leaching liquor and is difficult to separate in the later period; if the leaching rate is too low, the leaching efficiency is reduced, and the overall cost of the process is affected.

Preferably, in the above technical solution, an additive is further added into the leaching device, wherein the additive is one or more of ammonium sulfate, ammonium chloride, aluminum sulfate, aluminum chloride and magnesium sulfate; as a further preference, the additive is one or both of ammonium sulfate and ammonium chloride; the addition concentration of the additive is 0.5-4%. The ammonia radical ions are easy to exchange with the rare earth ions in the sediment, so that the rare earth in the sediment is easy to leach into the solution, and the addition of ammonium chloride and ammonium sulfate with proper concentrations is favorable for further increasing the leaching rate of the rare earth elements.

Preferably, the concentration of the deep sea sediments is 10% -60%; more preferably, the concentration of the deep sea sediments is 15-55%; the residence time of the deep sea sediment in the rare earth element leaching device is 30-2400 minutes, and preferably 60-1200 minutes. The process disclosed by the invention has the best extraction effect on the rare earth elements in the deep sea sediments with the concentration; meanwhile, when the retention time of the deep sea sediments in the rare earth element leaching device is 60-1200 minutes, the rare earth element extraction effect is optimal, if the retention time is too long, impurity ions can be leached, and if the retention time is too short, leaching is insufficient and the water content of leaching residues is too high.

Preferably, the flocculant is negative polyacrylamide, positive polyacrylamide or neutral polyacrylamide; the addition concentration of the flocculant is 0.05-0.15 g/L.

Preferably, the leaching device further comprises a rake frame, a transmission assembly and a shell with a slag discharge port formed at the lowest part of the bottom; the transmission assembly is arranged outside the shell and is connected with the rake rack; the rake frame is arranged above the bottom of the shell in parallel; the leachate outlet is arranged at the top of the shell; the reaction tank is arranged in the middle of the top of the shell, and a slurry outlet is formed in the bottom of the reaction tank.

The technical scheme is that the leaching device with the structure is selected to leach the rare earth elements in the deep sea sediment, so that the deep sea sediment, the acid liquor and the flocculating agent can react in the reaction tank with the stirring assembly, and the stirring assembly arranged in the reaction tank can ensure the normal flow of slurry in the device due to the poor flowability of the deep sea sediment and can improve the mixing condition of the acid liquor and the deep sea sediment, so that the leaching efficiency of the rare earth elements in the deep sea sediment is improved; the mixed slurry of the acid liquor and the deep sea sediments flows into the device from the slurry outlet at the bottom of the reaction tank to continue reacting, so that the dissolving reaction of the acid and the ores is further realized, meanwhile, leaching slag generated by the dissolving reaction grows up in the device under the action of a flocculating agent and settles to the bottom of the device, and the conical bottom structure and the rotatable rake frame connected with the conical bottom structure can ensure that the deposited leaching slag further grows up and moves to a slag discharge port, so that the leaching slag with low water content is finally discharged; the leachate separated in the growth process of the leaching slag floats upwards in the device and is collected through a leachate outlet; by the device and the method, when deep sea sediments are leached, a user does not need to dry the mined deep sea rare earth-rich sediments with high water content, the characteristic of slurried deep sea sediments can be directly utilized, acid is directly added for leaching reaction, the consumption of clear water can be effectively reduced, and meanwhile, a large amount of energy consumption required by the traditional drying treatment process is avoided.

And a first stirring assembly and a second stirring assembly are arranged in the reaction tank from top to bottom. By providing a plurality of stirring assemblies, the progress of the leaching reaction in the reaction tank can be further improved and the flow of the slurry can be promoted.

The first stirring assembly comprises a plurality of helical blades and is arranged at a position close to the joint of the reaction tank and the feeding pipeline. The first stirring component is designed into a spiral blade form, so that a spiral downward thrust can be applied to the leached slurry on the premise of ensuring the stirring strength, and the movement of the slurry in the reaction tank is promoted; the first stirring assembly is arranged at the position of the connection part of the reaction tank and the feeding pipeline, and the connection part is the feeding connection part, so that the deep sea sediment with poor liquidity is easy to accumulate at the connection part, and the blockage of the device is caused.

The second stirring assembly comprises a set of fan blades which are annularly arranged and vertically arranged along the vertical direction, and the second stirring assembly is arranged at a position close to the slurry outlet. The second stirring assemblies are arranged into a group of fan blades which are annularly arranged and vertically arranged along the vertical direction, so that a horizontal outward thrust can be applied to the leached pulp under the condition of ensuring the stirring strength, and the overflow of the lower-layer pulp from the reaction tank is promoted; the second stirring component is arranged at the position, close to the slurry outlet, of the bottom of the reaction tank, and the position is a position where the movement direction of the leached slurry is vertically turned to be horizontal, so that slurry with poor fluidity is easy to accumulate at the position, and the blockage of the device is caused.

Preferably, the included angle theta between the bus of the conical structure at the bottom of the reaction tank and the horizontal is more than or equal to 15 degrees; as a further preference, the angle is 30 DEG-theta-60 deg. The larger the included angle between the generatrix of the conical structure at the bottom of the reaction tank and the horizontal plane is, the stronger the stacking and extruding action between the sediments generated by gravity is, and therefore, the lower the water content of the leaching slag finally obtained from the slag discharge port is.

Compared with the prior art, the invention has the beneficial effects that:

the method for extracting the rare earth elements from the deep sea sediments disclosed by the method does not need to dry the exploited deep sea rare earth-rich sediments with high water content, and directly uses the pulpified characteristic of the sediments to directly carry out leaching reaction by acid. The consumption of clean water can be effectively reduced, and simultaneously, a large amount of energy consumption required in the traditional drying treatment process is avoided; meanwhile, the leaching rate of the rare earth elements is effectively improved by adding the additive under the condition that the acid dosage is obviously reduced. The acid dosage is reduced, the leaching of impurity elements is effectively avoided, and the subsequent leachate purification process is facilitated; the invention can simultaneously realize the leaching of the rare earth elements in the sediment and the separation of the leaching liquid and the leaching slag, and can also obtain the leaching slag with the water content of less than 40 percent, thereby simplifying the operation of the process flow and reducing the cost of the process.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic view of the construction of a leaching apparatus used in the method of example 1.

Illustration of the drawings:

1. a slag discharge port; 2. a rake rack; 3. a first stirring assembly; 4. a second stirring assembly; 5. a feeding pipeline; 6. a reaction tank; 7. a transmission assembly; 8. additive/acid/flocculant pipeline; 9. a leachate outlet; 10. a housing; 11. and a diffusion plate.

Detailed Description

In order to facilitate understanding of the invention, the invention will be described more fully and in detail with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.