Method for calculating amount of precipitant during extraction of rare earth leachate by carbonate precipitation method

Abstract

The invention discloses a method for calculating the use amount of a precipitator during extraction of a rare earth leaching solution through a carbonate precipitation method. The method comprises the following steps: obtaining the concentrations of aluminum ions, rare earth ions, ammonium ions and hydrogen ions in supernate obtained after the rare earth leaching solution is subjected to an impurity removal process through the carbonate precipitation method; respectively calculating the precipitant consumption for aluminum ion precipitation, rare earth ion precipitation, ammonium ion hydrolysis consumption and pH change consumption; and accumulating the use amounts of the precipitants to obtain the total use amount of the precipitants. According to the method, the reaction process of each ion of the rare earth leachate in the precipitation process is comprehensively considered, the concentration product theory and the hydrolysis theory are fully utilized, a theoretical calculation method for the use amount of the precipitant when the rare earth leachate is enriched through the carbonate precipitation method is provided, and a theoretical basis is provided for reasonably determining the use amount of the precipitant. The precipitator dosage determined by the method is scientific and reasonable, the error between the test result and the target pH value is within 2%, the error between the supernatant rare earth ion concentration and the target value is less than 10%, and the rare earth enrichment rate is greater than 99%.

Description

Technical Field

[0001] The invention belongs to the technical field of rare earth metallurgy, and in particular relates to a method for calculating the amount of a precipitant used in extracting a rare earth leaching solution by a carbonate precipitation method. Background Art

[0002] Ionic rare earth ores are chemically leached to obtain mother liquor containing rare earth ions. This mother liquor has problems such as high impurity content and low rare earth element concentration. It cannot be directly smelted and separated, so it needs to be treated accordingly. At present, the conventional treatment methods mainly include extraction and precipitation. The extraction method is still in the industrial trial stage due to its high cost and problems such as organic pollution in the raffinate. The method used in industrial sites is conventionally carbonate precipitation.

[0003] Currently, there is no industry standard for the process of enriching leachate by precipitation. The endpoint of the process is determined by the pH post-evaluation method. If the dosage is excessive, it will cause irreversible resource loss. Summary of the invention

[0004] The purpose of the present invention is to provide a method for calculating the amount of precipitant used in extracting rare earth leaching solution by carbonate precipitation method, which can reasonably determine the amount of precipitant used.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: a method for calculating the amount of precipitant used in the extraction of rare earth leaching solution by carbonate precipitation method, comprising the following steps:

[0006] Obtaining the concentrations of aluminum ions, rare earth ions, ammonium ions and hydrogen ions in the supernatant of the rare earth leaching solution after the impurity removal process by carbonate precipitation method;

[0007] Calculate the amount of precipitant consumed by aluminum ion precipitation, rare earth ion precipitation, ammonium ion hydrolysis and pH change respectively;

[0008] The total precipitant dosage was obtained by adding up the dosages of each precipitant.

[0009] The carbonate precipitation method includes an impurity removal process and a precipitation process; wherein the impurity removal process is specifically as follows: the pH of the rare earth leaching solution is adjusted by adding carbonates to precipitate aluminum ions to obtain a supernatant; the precipitation process is specifically as follows: the supernatant generates rare earth carbonate precipitates under the action of a new round of added carbonates to obtain a rare earth product.

[0010] Reactions in the precipitation process include:

[0011] 1) Aluminum ion Al 3+ Precipitation: Aluminum ion precipitation produces aluminum hydroxide. Considering that the pH is high enough, Al 3+ When the precipitation is complete, the reaction equation (1) is expressed as:

[0012]

[0013] 2)Rare earth ions RE 3+ Precipitation: Rare earth ions are transformed into rare earth carbonate crystals, and the reaction equation (2) is expressed as:

[0014]

[0015] 3) Ammonium ion NH4 + Changes in concentration: Under the action of hydroxide ions, NH4 + Hydrolysis occurs, and the reaction equation (3) is expressed as:

[0016]

[0017] in, is the hydrolysis constant of ammonium ion;

[0018] 4) H + Source: Hydrogen ion consumption comes from the hydrolysis of bicarbonate ions and the dissociation of water, which can be expressed by reaction equations (4) to (6):

[0019]

[0020] Among them, k w is the ionic product constant of water.

[0021] The specific calculation method for the amount of precipitant used for aluminum ion precipitation is:

[0022] According to the reaction equation (1), the amount of precipitant M for aluminum ion precipitation is obtained by the law of charge conservation: 沉淀剂-Al It is expressed as:

[0023]

[0024] Among them, M r(沉淀剂) is the relative molecular weight of the precipitant, is the concentration of aluminum ions in the supernatant.

[0025] The specific calculation method for the amount of precipitant used for rare earth ion precipitation is:

[0026] According to reaction equation (2), the amount of precipitant M for rare earth ion precipitation is obtained by the law of charge conservation: 沉淀剂-RE It is expressed as:

[0027]

[0028] in, is the bicarbonate ion concentration consumed by the precipitation of rare earth ions, is the concentration of rare earth ions in the supernatant, is the concentration of rare earth ions at the end point of precipitation.

[0029] The specific method for calculating the amount of precipitant consumed by ammonium ion hydrolysis is:

[0030] According to reaction equations (3), (4) and (6), the amount of precipitant consumed by ammonium ion hydrolysis is obtained by the law of charge conservation: 沉淀剂-NH It is expressed as:

[0031]

[0032] in, pH * is the pH value at the precipitation end point, pH 0 is the initial pH value of the supernatant.

[0033] The specific method for calculating the amount of precipitant consumed by pH change is:

[0034] According to reaction equation (4), the amount of precipitant consumed by pH change is obtained by the law of charge conservation: 沉淀剂-H It is expressed as:

[0035]

[0036] The total precipitant dosage is expressed as:

[0037] M 沉淀剂-总 =M 沉淀剂-Al +M 沉淀剂-Re +M 沉淀剂-NH +M 沉淀剂-H (11)

[0038] Among them, M 沉淀剂-总 is the total precipitant dosage.

[0039] A computer device is also provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the above methods when executing the computer program.

[0040] A computer-readable storage medium is also provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of any of the above methods are implemented.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention comprehensively considers the reaction process of each ion in the rare earth leaching solution in the precipitation process, makes full use of the concentration product theory and the hydrolysis theory, and proposes a theoretical calculation method for the amount of precipitant used when the rare earth leaching solution is enriched by the carbonate precipitation method, which provides a theoretical basis for reasonably determining the amount of precipitant used. The amount of precipitant used determined by the present invention is scientific and reasonable, the error between the test result and the target pH value is within 2%, the error between the rare earth ion concentration of the supernatant and the target value is less than 10% (0.0012mmol / L), and the rare earth enrichment rate is greater than 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of a flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] The technical solution of the present invention is: a method for calculating the amount of precipitant used when extracting rare earth leaching solution by carbonate precipitation method, such as Figure 1 As shown, the following steps are included:

[0046] Obtaining the concentrations of aluminum ions, rare earth ions, ammonium ions and hydrogen ions in the supernatant of the rare earth leaching solution after the impurity removal process in the carbonate precipitation method;

[0047] Calculate the amount of precipitant consumed for aluminum ion precipitation, rare earth ion precipitation, ammonium ion hydrolysis and pH change respectively, all in kg / m 3 ;

[0048] The total precipitant dosage was obtained by adding up the dosages of each precipitant.

[0049] The carbonate precipitation method includes an impurity removal process and a precipitation process; wherein, the impurity removal process is specifically as follows: the pH of the rare earth leaching solution is adjusted to about 5.2 by adding carbonate, so that aluminum ions are precipitated to obtain a supernatant; the precipitation process is specifically as follows: the supernatant generates rare earth carbonate precipitate under the action of a new round of added carbonate to obtain a rare earth product.

[0050] Reactions in the precipitation process include:

[0051] 1) Aluminum ion Al 3+ Precipitation: Aluminum ion precipitation produces aluminum hydroxide. Considering that the pH is high enough, Al 3+ When the precipitation is complete, the reaction equation (1) is expressed as:

[0052]

[0053] 2)Rare earth ions RE 3+ Precipitation: rare earth ions are converted into rare earth carbonate crystals. In this embodiment, RE in the supernatant after the final precipitation is complete 3+ The concentration is 0.02g / L (1.3*10 -4 mol / L), the reaction equation (2) is expressed as:

[0054]

[0055] 3) Ammonium ion NH4 + Changes in concentration: Under the action of hydroxide ions, NH4 + Hydrolysis occurs, and the reaction equation (3) is expressed as:

[0056]

[0057] in, is the hydrolysis constant of ammonium ion;

[0058] 4) H + (OH - ) Source: Hydrogen ion consumption (hydroxyl ion production) comes from the hydrolysis of bicarbonate ions and the dissociation of water, which can be expressed by reaction equations (4) to (6):

[0059]

[0060] As can be seen from the above, the overall reaction of the precipitation process includes: (1) aluminum ion precipitation to produce aluminum hydroxide; (2) rare earth ions to produce rare earth carbonate precipitation; (3) changes in the degree of hydrolysis of ammonium ions; (4) changes in pH (hydrogen ion-hydroxyl ion) concentration. Therefore, based on the above chemical reaction process, the amount of precipitant can be theoretically calculated under a given endpoint pH. This can provide a theoretical basis and technical guidance for the subsequent automation of rare earth mother liquor treatment by carbonate precipitation method.

[0061] The specific calculation method for the amount of precipitant used for aluminum ion precipitation is:

[0062] According to the reaction equation (1), the amount of precipitant M for aluminum ion precipitation is obtained by the law of charge conservation: 沉淀剂-Al It is expressed as:

[0063]

[0064] Among them, M r(沉淀剂) is the relative molecular weight of the precipitant, is the concentration of aluminum ions in the supernatant.

[0065] The specific calculation method for the amount of precipitant used for rare earth ion precipitation is:

[0066] According to reaction equation (2), the amount of precipitant M for rare earth ion precipitation is obtained by the law of charge conservation: 沉淀剂-RE It is expressed as:

[0067]

[0068] in, is the bicarbonate ion concentration consumed by the precipitation of rare earth ions, mol / L; is the concentration of rare earth ions in the supernatant; is the concentration of rare earth ions at the end point of precipitation, mol / L (1.3*10-4mol / L in the embodiment of the present invention).

[0069] The specific method for calculating the amount of precipitant consumed by ammonium ion hydrolysis is:

[0070] According to reaction equations (3), (4) and (6), the amount of precipitant consumed by ammonium ion hydrolysis is obtained by the law of charge conservation: 沉淀剂-NH It is expressed as:

[0071]

[0072] in, pH * is the pH value at the precipitation end point, pH 0 is the initial pH value of the supernatant.

[0073] The specific method for calculating the amount of precipitant consumed by pH change is:

[0074] According to reaction equation (4), the amount of precipitant consumed by pH change is obtained by the law of charge conservation: 沉淀剂-H It is expressed as:

[0075]

[0076] The total precipitant dosage is expressed as:

[0077] M 沉淀剂-总 =M 沉淀剂-Al +M 沉淀剂-Re +M 沉淀剂-NH +M 沉淀剂-H (11)

[0078] Among them, M 沉淀剂-总 is the total precipitant dosage.

[0079] In the present embodiment, the ion content of three leachates with different properties was tested, and the results are shown in Table 1:

[0080] Table 1

[0081]

[0082] Ammonium bicarbonate and sodium bicarbonate were used as precipitants, respectively, with a pH of 7.0 as the end point and a rare earth ion concentration of 1.3*10 -4 mol / L is the endpoint rare earth ion concentration. The precipitant dosage is calculated and the precipitant dosage table is shown in Table 2. The units of each parameter in the table are kg / m 3 :

[0083] Table 2

[0084]

[0085]

[0086] According to M in Table 2 沉淀剂-总 The precipitation experiment was carried out on the leachate with the dosage of , and the results are shown in Table 3:

[0087] Table 3

[0088]

[0089]

[0090] As can be seen from the above table, according to the theoretical calculation of the precipitant dosage of the present invention, the error between the test result and the target pH value is within 2%, the error between the rare earth ion concentration of the supernatant and the target value is less than 10% (0.0012mmol / L), and the rare earth enrichment rate is greater than 99%, indicating that the precipitant dosage determined by this method is scientific and reasonable.

[0091] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for calculating the amount of precipitant used in the extraction of rare earth leaching solution by carbonate precipitation method, characterized in that: The following steps are involved: Obtaining the concentrations of aluminum ions, rare earth ions, ammonium ions and hydrogen ions in the supernatant of the rare earth leaching solution after the impurity removal process by carbonate precipitation method; Calculate the amount of precipitant consumed by aluminum ion precipitation, rare earth ion precipitation, ammonium ion hydrolysis and pH change respectively; The total precipitant dosage was obtained by adding up the dosages of each precipitant.

2. The method for calculating the amount of precipitant used in the carbonate precipitation extraction of rare earth leachate according to claim 1, characterized in that: The carbonate precipitation method includes an impurity removal process and a precipitation process; wherein the impurity removal process is specifically as follows: the pH of the rare earth leaching solution is adjusted by adding carbonates to precipitate aluminum ions to obtain a supernatant; the precipitation process is specifically as follows: the supernatant generates rare earth carbonate precipitates under the action of a new round of added carbonates to obtain a rare earth product.

3. The method for calculating the amount of precipitant used in the carbonate precipitation extraction of rare earth leaching solution according to claim 2, characterized in that: Reactions in the precipitation process include: 1) Aluminum ion Al 3+ Precipitation: Aluminum ion precipitation produces aluminum hydroxide. Considering that the pH is high enough, Al 3+ When the precipitation is complete, the reaction equation (1) is expressed as: 2)Rare earth ions RE 3+ Precipitation: Rare earth ions are transformed into rare earth carbonate crystals, and the reaction equation (2) is expressed as: 3) Ammonium ion NH4 + Changes in concentration: Under the action of hydroxide ions, NH4 + Hydrolysis occurs, and the reaction equation (3) is expressed as: in, is the hydrolysis constant of ammonium ion; 4) H + Source: Hydrogen ion consumption comes from the hydrolysis of bicarbonate ions and the dissociation of water, which can be expressed by reaction equations (4) to (6): Among them, k w is the ionic product constant of water.

4. The method for calculating the amount of precipitant used in the carbonate precipitation extraction of rare earth leaching solution according to claim 3, characterized in that: The specific calculation method for the amount of precipitant used for aluminum ion precipitation is: According to the reaction equation (1), the amount of precipitant M for aluminum ion precipitation is obtained by the law of charge conservation: 沉淀剂-Al It is expressed as: Among them, M r(沉淀剂) is the relative molecular weight of the precipitant, is the concentration of aluminum ions in the supernatant.

5. The method for calculating the amount of precipitant used in the carbonate precipitation extraction of rare earth leaching solution according to claim 4, characterized in that: The specific calculation method for the amount of precipitant used for rare earth ion precipitation is: According to reaction equation (2), the amount of precipitant M for rare earth ion precipitation is obtained by the law of charge conservation: 沉淀剂-RE It is expressed as: in, is the bicarbonate ion concentration consumed by the precipitation of rare earth ions, is the concentration of rare earth ions in the supernatant, is the concentration of rare earth ions at the end point of precipitation.

6. The method for calculating the amount of precipitant used in the carbonate precipitation extraction of rare earth leaching solution according to claim 5, characterized in that: The specific method for calculating the amount of precipitant consumed by ammonium ion hydrolysis is: According to reaction equations (3), (4) and (6), the amount of precipitant consumed by ammonium ion hydrolysis is obtained by the law of charge conservation: 沉淀剂-NH It is expressed as: in, pH * is the pH value at the precipitation end point, pH 0 is the initial pH value of the supernatant.

7. The method for calculating the amount of precipitant used in the carbonate precipitation extraction of rare earth leaching solution according to claim 6, characterized in that: The specific method for calculating the amount of precipitant consumed by pH change is: According to reaction equation (4), the amount of precipitant consumed by pH change is obtained by the law of charge conservation: 沉淀剂-H It is expressed as:

8. The method for calculating the amount of precipitant used in the carbonate precipitation extraction of rare earth leaching solution according to claim 7, characterized in that: The total precipitant dosage is expressed as: M 沉淀剂-总 =M 沉淀剂-Al +M 沉淀剂-Re +M 沉淀剂-NH +M 沉淀剂-H (11) Among them, M 沉淀剂-总 is the total precipitant dosage.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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