CN106755995A - A kind of process for separating and recovering of rare earth containing rare earth phosphate rock and phosphorus - Google Patents

Abstract

The invention discloses a process for separating and recovering rare earth and phosphorus from phosphate rock containing rare earth. First, phosphoric acid is added to the rare earth phosphate rock to form a pulp; The organic phase is separated from the pulp to obtain the organic phase containing rare earth ions and the phosphorus-containing pulp. The rare earth-containing solution is obtained by analyzing the rare earth in the organic phase. At the same time, sulfuric acid is added to the separated phosphorus-containing pulp to generate solid products. Phosphoric acid is a liquid product; finally, the phosphoric acid solution is obtained by solid-liquid separation of phosphogypsum and phosphoric acid. The invention has the characteristics of high rare earth leaching rate, and the leaching rate can reach more than 50%.

Description

A separation and recovery process of rare earth and phosphorus in phosphate rock containing rare earth

technical field

The invention relates to a process for separating and recovering ions in phosphate rock, in particular to a process for separating and recovering rare earth and phosphorus in phosphate rock containing rare earth.

Background technique

Rare earth elements in phosphate rock mainly exist in phosphorus-containing minerals in the form of isomorphism. In the production process of wet phosphoric acid, it is necessary to ensure that the phosphate rock and acid fully react so that the rare earth elements can be released from the apatite lattice. , the existing industrial process for producing wet-process phosphoric acid is to add sulfuric acid to leach the ore after pretreatment of phosphate rock with dilute phosphoric acid (the concentration of phosphoric acid is about 10%), and to separate the solid product phosphogypsum from the liquid product phosphoric acid after the full reaction. During the process, the rare earth elements in the phosphate rock enter the phosphogypsum lattice or are wrapped by the phosphogypsum during the crystallization process, thereby reducing the leaching rate of the rare earth to less than 30%.

Contents of the invention

The object of the present invention is to provide a separation and recovery process of rare earth and phosphorus in rare earth-containing phosphate rock. The invention has the characteristics of high rare earth leaching rate, and the leaching rate can reach more than 50%.

The technical scheme of the present invention: a process for separating and recovering rare earth and phosphorus from rare earth-containing phosphate rock, comprising the following steps:

(1) adding phosphoric acid to the rare earth-containing phosphate rock for decomposition reaction to obtain ore pulp;

(2) adding an organic phosphine extractant in stages to the ore pulp to obtain rare earth enriched ore pulp;

(3) separating the rare earth-enriched ore pulp to obtain a rare earth-containing organic phase and a phosphorous-containing ore pulp;

(4) analyzing the rare earth-containing organic phase separated in step (3) to obtain an organic phase and a solution containing rare earth ions;

(5) adding sulfuric acid to the phosphorus-containing pulp separated in step (3) to generate a solid product phosphogypsum and a liquid product phosphoric acid, and performing solid-liquid separation of the phosphogypsum and phosphoric acid to obtain a phosphoric acid solution.

In the aforementioned rare earth-containing phosphate rock separation and recovery process for rare earth and phosphorus, in the step (1), the concentration of phosphoric acid is 10-50%.

In the aforementioned rare earth-containing phosphate rock separation and recovery process for rare earth and phosphorus, the concentration of phosphoric acid is 25-35%.

The aforementioned separation and recovery process of rare earth-containing phosphate rock rare earth and phosphorus, in the step (2), the organic phosphine extractant is added in 2 times, the amount added for the first time is 35-45% of the total amount, and the remaining organic phosphine extractant Add after 10-20 minutes after the first addition.

In the above-mentioned separation and recovery process of rare earth and phosphorus in rare earth-containing phosphate rock, the amount of the organic phosphine extractant added for the first time is 40% of the total amount, and the remaining organic phosphine extractant is added 10 minutes after the first addition.

In the aforementioned rare earth-containing phosphate rock separation and recovery process for rare earth and phosphorus, the organic phosphine extractant is an acidic phosphine extractant.

In the aforementioned rare earth-containing phosphate rock rare earth and phosphorus separation and recovery process, the acidic phosphine extractant is one of di(2-ethylhexyl) phosphate and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester one or both.

In the aforementioned rare earth-containing phosphate rock separation and recovery process for rare earth and phosphorus, in the step (3), the separated rare earth-containing organic phase is recycled for extraction in step (2).

The aforementioned rare earth-containing phosphate rock rare earth and phosphorus separation and recovery process, in the step (4), the organic phase obtained by analysis is recycled for the extraction in the step (2); the phosphoric acid solution in the step (5) is used for recycling Phosphoric acid decomposition reaction in step (1).

In the aforementioned rare earth-containing phosphate rock rare earth and phosphorus separation and recovery process, in the step (5), the sulfuric acid added is industrial sulfuric acid with a concentration of 93-98%, and the excess coefficient of sulfuric acid added is 0.8-1.2.

Beneficial effects of the present invention:

1. In the present invention, by adding an organic extractant in the phosphoric acid leaching ore process, the rare earth elements in the ore react with phosphoric acid to generate rare earth ions into the solution, and are first extracted into the organic phase by the organic solvent, and then the rare earth-enriched organic The phase is separated from the pulp, and at this time, sulfuric acid is added to the pulp to generate phosphoric acid, which reduces the encapsulation or crystallization of rare earths during the formation of phosphogypsum, thereby increasing the leaching rate of rare earths from below 30% to above 50%.

2. In the prior art, the organic phosphine extractant is added to the rare earth-containing phosphoric acid solution after the separation of phosphogypsum for rare earth extraction, but in the present invention, the organic phosphine extractant is directly added to the rare earth-containing phosphate rock and phosphoric acid. In the ore slurry, the rare earth can be extracted into the organic phase while reducing the saturation of the rare earth in the slurry, so that the rare earth in the ore can continue to react and be continuously extracted into the organic phase, thereby increasing the leaching rate of the rare earth.

3. An organic phosphine extractant is added to the decomposition reaction of rare earth-containing phosphate rock and phosphoric acid. Since the organic phosphine extractant has a certain viscosity, one-time addition will reduce the progress of the leaching reaction, thereby reducing the leaching rate of the soil. The inventors found that adding the organic phosphine extractant in stages can reduce the influence of the viscosity of the extractant on the decomposition reaction. Therefore, the present invention increases the leaching rate of rare earths by adding in stages.

4. The inventor found that the time and ratio of adding the organic phosphine extractant in stages is also very important. If the time and ratio of adding the organic phosphine extracting agent in stages are not well controlled, it will also affect the normal progress of the decomposition reaction. Therefore, the invention After a large number of studies, people have found that the "organic phosphine extractant" of the present invention is added in two times, the first added amount is 35-45% of the total amount, and the remaining organic phosphine extractant is added after 10-20 minutes after the first addition "The technology can not only reduce the influence of the viscosity of the extractant on the decomposition reaction, but also not affect the smooth progress of the decomposition reaction.

5. The extractant of the present invention contains a hydroxyl group, and the H ⁺ on the hydroxyl group is easily replaced by RE ⁺ , and P=0 is easily coordinated with RE ⁺ . Therefore, the extractant of the present invention can be used no matter at high acidity or low acidity. Under the condition of acidity, it can form stable complexes with rare earths, so it has high extraction capacity.

6. In the present invention, the leaching rate of rare earth is further improved by returning the rare earth-containing organic phase to the extraction step for repeated extraction.

7. The present invention reduces the input of materials and saves the cost by recycling the resolved organic phase for extraction.

8. In the present invention, the phosphoric acid prepared by this system is used in the decomposition reaction of phosphate rock, which reduces the investment of outsourcing and further saves the cost.

Rare earth leaching rate under existing wet phosphoric acid leaching conditions:

Add 10% phosphoric acid to the rare earth-containing phosphate rock to make a slurry with a liquid-solid ratio of 3:1, and then add 98% sulfuric acid for leaching reaction. The amount of sulfuric acid is the theoretical amount, and the leaching temperature is 75-80°C. Solid-liquid separation. The leaching rate of P ₂ O ₅ is 90.17%, and the leaching rate of rare earth is 10.51%.

Add 25% phosphoric acid to the rare earth-containing phosphate rock to make a slurry with a liquid-solid ratio of 3:1, and then add 98% sulfuric acid for leaching reaction. The amount of sulfuric acid is the theoretical amount. The leaching temperature is 75-80°C. Solid-liquid separation. The leaching rate of P ₂ O ₅ is 91.90%, and the leaching rate of rare earth is 23.68%.

Add 50% phosphoric acid to the rare earth-containing phosphate rock to make a slurry with a liquid-solid ratio of 3:1, and then add 98% sulfuric acid for leaching reaction. The amount of sulfuric acid is the theoretical amount, and the leaching temperature is 75-80°C. Solid-liquid separation. The leaching rate of P ₂ O ₅ is 92.48%, and the leaching rate of rare earth is 29.05%.

detailed description

The present invention will be further described below in conjunction with the examples, but not as a basis for limiting the present invention.

Embodiment 1: a kind of rare earth-containing phosphate rock rare earth and phosphorus separation recovery process, comprises the following steps:

(1) adding phosphoric acid with a concentration of 30-34% in the rare earth-containing phosphate rock for decomposition reaction to obtain ore pulp;

(2) Add bis(2-ethylhexyl) phosphate in 2 times in the pulp, the amount added for the first time is 40% of the total amount, and the remaining organic phosphine extractant is added after 10 minutes after the first addition to obtain rare earth rich collection pulp;

(3) separating the rare earth-enriched ore pulp to obtain a rare earth-containing organic phase and a phosphorous-containing ore pulp;

(4) returning the separated rare earth-containing organic phase to step (2) for repeated leaching, and then performing the pulp separation in step (3) to obtain a rare earth-containing organic phase and phosphorus-containing pulp;

(5) analyzing the rare earth-containing organic phase separated in step (4) to obtain an organic phase and a rare earth ion-containing solution;

(6) add sulfuric acid in the phosphorus-containing ore slurry that separates and obtain in step (3), the concentration of sulfuric acid is 95%, and the excess coefficient that sulfuric acid adds is 1, generates solid product phosphogypsum and liquid product phosphoric acid, carries out phosphogypsum and phosphoric acid Phosphoric acid solution is obtained by solid-liquid separation;

(7) In step (4), the organic phase obtained by analysis is recycled for extraction in step (2).

The rare earth leaching rate of this embodiment is about 70%, and the leaching rate of P ₂ O ₅ is about 95.18%, both of which are higher than the leaching rates of rare earth and P ₂ O ₅ in the prior art.

Embodiment 2: a kind of rare earth-containing phosphate rock rare earth and phosphorus separation recovery process, comprises the following steps:

(1) adding phosphoric acid with a concentration of 10-30% to the rare earth-containing phosphate rock for decomposition reaction to obtain ore pulp;

(2) Add 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester in 2 times in the pulp, the amount added for the first time is 35% of the total amount, and the remaining organic phosphine extractant is added after 8 minutes after the first addition , to obtain rare earth enriched pulp;

(3) separating the rare earth-enriched ore pulp to obtain a rare earth-containing organic phase and a phosphorous-containing ore pulp;

(4) analyzing the rare earth-containing organic phase separated in step (3) to obtain an organic phase and a solution containing rare earth ions;

(5) add sulfuric acid in the phosphorus-containing ore slurry that separates in step (3), the concentration of sulfuric acid is 93%, and the excess coefficient that sulfuric acid adds is 0.8, generates solid product phosphogypsum and liquid product phosphoric acid, carries out phosphogypsum and phosphoric acid Phosphoric acid solution is obtained by solid-liquid separation;

(6) The phosphoric acid solution in the step (5) is recycled for the phosphoric acid decomposition reaction in the step (1).

The rare earth leaching rate of this example is about 56%, and the leaching rate of P ₂ O ₅ is about 92.32%, both of which are higher than the leaching rates of rare earth and P ₂ O ₅ in the prior art, but lower than the leaching rate of Example 1.

Embodiment 3: a kind of rare earth-containing phosphate rock rare earth and phosphorus separation recovery process, comprises the following steps:

(1) adding phosphoric acid with a concentration of 35-50% in the rare earth-containing phosphate rock for decomposition reaction to obtain ore pulp;

(2) Add 50% each of bis (2-ethylhexyl) phosphate and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester in 2 times in the pulp, and the amount added for the first time is 45% of the total amount, The remaining organic phosphine extractant is added 15 minutes after the first addition to obtain rare earth enriched ore pulp;

(3) separating the rare earth-enriched ore pulp to obtain a rare earth-containing organic phase and a phosphorous-containing ore pulp;

(4) analyzing the rare earth-containing organic phase separated in step (3) to obtain an organic phase and a solution containing rare earth ions;

(5) add sulfuric acid in the phosphorus-containing ore slurry that separates in step (3), the concentration of sulfuric acid is 98%, and the excess coefficient that sulfuric acid adds is 1.2, generates solid product phosphogypsum and liquid product phosphoric acid, carries out phosphogypsum and phosphoric acid Phosphoric acid solution is obtained by solid-liquid separation;

(6) In step (4), the organic phase obtained by analysis is recycled for extraction in step (2);

(7) The phosphoric acid solution in step (5) is recycled for the phosphoric acid decomposition reaction in step (1).

The rare earth leaching rate of this embodiment is about 62%, and the leaching rate of P ₂ O ₅ is about 93.11%, which are all higher than the leaching rates of rare earth and P ₂ O ₅ in the prior art, but lower than the leaching rate of Example 1, Higher than the leaching rate of Example 2.

Embodiment 4: a kind of rare earth-containing phosphate rock rare earth and phosphorus separation recovery process, comprises the following steps:

(1) adding phosphoric acid with a concentration of 35-50% in the rare earth-containing phosphate rock for decomposition reaction to obtain ore pulp;

(2) Add bis(2-ethylhexyl) phosphate in 3 times in the pulp, the amount added for the first time is 30% of the total amount, the amount added for the second time is 40% of the total amount, and the amount added for the third time is 40% of the total amount. The amount is 30% of the total amount, and the time interval between each addition is 12 minutes to obtain rare earth enriched ore pulp;

(3) separating the rare earth-enriched ore pulp to obtain a rare earth-containing organic phase and a phosphorous-containing ore pulp;

(4) analyzing the rare earth-containing organic phase separated in step (3) to obtain an organic phase and a solution containing rare earth ions;

(5) add sulfuric acid in the phosphorus-containing ore slurry that separates in step (3), the concentration of sulfuric acid is 94%, and the excess coefficient that sulfuric acid adds is 0.9, generates solid product phosphogypsum and liquid product phosphoric acid, carries out phosphogypsum and phosphoric acid Phosphoric acid solution is obtained by solid-liquid separation;

(6) In step (4), the organic phase obtained by analysis is recycled for extraction in step (2);

(7) The phosphoric acid solution in step (5) is recycled for the phosphoric acid decomposition reaction in step (1).

The rare earth leaching rate of this embodiment is about 68%, and the leaching rate of P ₂ O ₅ is about 94.47%, which are all higher than the leaching rates of rare earth and P ₂ O ₅ in the prior art, but lower than the leaching rate of Example 1, Higher than the leaching rate of Example 2 and Example 3.

Embodiment 5: a kind of rare earth-containing phosphate rock rare earth and phosphorus separation recovery process, comprises the following steps:

(1) adding phosphoric acid with a concentration of 35-50% in the rare earth-containing phosphate rock for decomposition reaction to obtain ore pulp;

(2) adding bis(2-ethylhexyl) phosphate in 5 times in the pulp, the amount added each time is 20% of the total amount, and the time interval of adding each time is after 8 minutes to obtain the rare earth enriched pulp;

(3) separating the rare earth-enriched ore pulp to obtain a rare earth-containing organic phase and a phosphorous-containing ore pulp;

(4) analyzing the rare earth-containing organic phase separated in step (3) to obtain an organic phase and a solution containing rare earth ions;

(5) add sulfuric acid in the phosphorus-containing ore slurry that separates in step (3), the concentration of sulfuric acid is 97%, and the excess coefficient that sulfuric acid adds is 1.1, generates solid product phosphogypsum and liquid product phosphoric acid, carries out phosphogypsum and phosphoric acid Phosphoric acid solution is obtained by solid-liquid separation;

(6) In step (4), the organic phase obtained by analysis is recycled for extraction in step (2);

(7) The phosphoric acid solution in step (5) is recycled for the phosphoric acid decomposition reaction in step (1).

The rare earth leaching rate of this embodiment is about 66%, and the leaching rate of _P2O5 is about 93.86%, which are all higher than the leaching rates of rare earth and _P2O5 in the prior art, but lower than those of Examples ₁ and ₄ . The leaching rate is higher than the leaching rate of embodiment 2 and embodiment 3.

Claims (10)

1. A separation and recovery process of rare earth-containing phosphate rock rare earth and phosphorus, characterized in that: comprising the steps: (1) Add phosphoric acid to rare earth-containing phosphate rock for decomposition reaction to obtain ore pulp; (2) Add organic phosphine extractant to the pulp in stages to obtain rare earth enriched pulp; (3) Separating the rare earth-enriched pulp to obtain rare earth-containing organic phase and phosphorous-containing pulp; (4) Analyzing the rare earth-containing organic phase separated in step (3) to obtain an organic phase and a rare earth ion-containing solution; (5) Sulfuric acid is added to the phosphorus-containing pulp separated in step (3) to generate solid product phosphogypsum and liquid product phosphoric acid, and the phosphoric acid solution is obtained by solid-liquid separation of phosphogypsum and phosphoric acid. 2. The separation and recovery process of rare earth and phosphorus from rare earth-containing phosphate rock according to claim 1, characterized in that: in the step (1), the concentration of phosphoric acid is 10-50%. 3. The separation and recovery process of rare earth and phosphorus in rare earth-containing phosphate rock according to claim 2, characterized in that: the concentration of phosphoric acid is 25-35%. 4. The separation and recovery process of rare earth and phosphorus from rare earth-containing phosphate rock according to claim 1, characterized in that: in the step (2), the organic phosphine extractant is added in two times, and the amount added for the first time is the total 35-45%, the remaining organic phosphine extractant is added after 10-20 minutes after the first addition. 5. The separation and recovery process of rare earth-containing phosphate rock rare earth and phosphorus according to claim 4, characterized in that: the amount of the organic phosphine extractant added for the first time is 40% of the total amount, and the remaining organic phosphine extractant is used for the first time Add after 10 minutes after addition. 6. The separation and recovery process of rare earth and phosphorus in rare earth-containing phosphate rock according to claim 1, characterized in that: the organic phosphine extractant is an acidic phosphine extractant. 7. The separation and recovery process of rare earth-containing phosphate rock rare earth and phosphorus according to claim 6, characterized in that: the acidic phosphine extractant is di(2-ethylhexyl) phosphate and 2-ethylhexylphosphine One or two kinds of acid mono-2-ethylhexyl ester. 8. The separation and recovery process of rare earth and phosphorus from rare earth-containing phosphate rock according to claim 1, characterized in that in the step (3), the separated rare earth-containing organic phase is recycled for extraction in step (2) . 9. The separation and recovery process of rare earth and phosphorus from rare earth-containing phosphate rock according to claim 1, characterized in that: in the step (4), the organic phase obtained by analysis is recycled for the extraction in the step (2); The phosphoric acid solution in step (5) is recycled for the phosphoric acid decomposition reaction in step (1). 10. The separation and recovery process of rare earth and phosphorus from rare earth-containing phosphate rock according to claim 1, characterized in that: in the step (5), the sulfuric acid added is industrial sulfuric acid with a concentration of 93-98%, and the excess sulfuric acid added The coefficient is 0.8-1.2.