Design method of segmented reverse extraction linkage extraction process of mixed rare earth-loaded organic phase

Abstract

The invention relates to a design method of a staged reverse extraction linkage extraction process of a loaded mischmetal organic phase, which comprises the following steps: designing a cascade extraction separation equipment process framework, and determining an aqueous phase outlet, an organic phase outlet and components; the cascade extraction and separation equipment is divided into t-1 extraction and separation sections, and one extraction and separation section is arranged between every two outlets; calculating the total flow and the partial flow of each component flowing out of a water phase outlet at the left end of the (t-1) th extraction separation section; calculating the shunt volume of each component in the water phase led out from the left ends of the (t-2) th extraction separation section, the (t-3) th extraction separation section and the (t-2) th extraction separation section; calculating the shunt volume of two components in a water phase led out from a left end outlet of the first extraction separation section, the flow of an organic phase A1 component led out from a right end outlet, and the flow of a back extractant led in from a right end inlet; and calculating the number of the extractors required by each separation section in a step-by-step recursion manner. According to the method provided by the invention, the separation work of the back-extractant can be fully utilized under the condition of approaching the theoretical minimum back-extractant consumption.

Description

Technical Field

[0001] The invention belongs to the technical field of rare earth hydrometallurgy, and in particular relates to a design method for a segmented stripping linkage extraction process of an organic phase loaded with mixed rare earths. Background Art

[0002] my country's Baotou mixed rare earth ore is the world's largest single rare earth deposit. Its complex mineral structure and composition, combined with the coexistence of bastnaesite and monazite, make smelting and separation difficult. Currently, the mainstream process for smelting and separation of Baotou's mixed light rare earth ore involves roasting the ore with concentrated sulfuric acid, followed by water leaching and magnesium oxide impurity removal to obtain a pure sulfate rare earth leachate. This leachate is then transformed to produce a mixed rare earth chloride solution, which is then extracted and separated using P507. Finally, precipitation and calcination are performed to produce single or mixed rare earth oxide products.

[0003] In this mainstream process, the transformation of rare earth sulfate leaching solution into rare earth chloride solution can be achieved through two technical routes: one is to obtain rare earth carbonate by ammonium carbonate precipitation and then dissolve it in hydrochloric acid to obtain high-concentration rare earth chloride. This process requires low investment, but will produce ammonia nitrogen wastewater with high treatment costs; the other is to use saponified P507 (or P204) extraction agent for full extraction and then transform it into a high-concentration rare earth chloride solution through hydrochloric acid back extraction, which is used as the feed liquid for subsequent extraction and separation. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a design method for a segmented stripping linkage extraction process of a mixed rare earth loaded organic phase, aiming to provide a process for the transformation of the rare earth sulfate aqueous extract, in which the extracted organic phase containing all rare earths is stripped segmentally, and through optimized design, the separation work of the stripping agent is maximized to achieve the enrichment of different components at different outlets, thereby reducing the acid and alkali consumption of the overall separation process, reducing production costs and the amount of salt-containing wastewater generated.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a design method for a segmented stripping linkage extraction process for a mixed rare earth loaded organic phase, the method comprising the following steps:

[0006] S1. Design the process framework of the cascade extraction and separation equipment according to the number of components t (t is an integer ≥ 2) of the organic phase loaded with mixed rare earths, and determine the aqueous phase outlet, organic phase outlet and components of the cascade extraction;

[0007] S2. Divide the cascade extraction and separation equipment into t-1 extraction and separation sections, with each section between two outlets being an extraction and separation section, and mark them as extraction and separation sections 1, 2, ..., t-2, and t-1 from right to left; if t>2, proceed to step S3; if t=2, proceed to step S6;

[0008] S3. Analysis of the extraction and separation section t-1: Based on the fractional flow of each rare earth component in the loaded organic phase introduced from the left end of the cascade extraction and separation equipment And the total flow f o Calculate the total flow rate x of each component flowing out of the left end water phase outlet of the t-1 extraction separation section t-1 , calculate the fractional flow rate of each component flowing out of the left end water phase outlet of the t-1 extraction separation section If t>3, then go to step S4; if t=3, then go to step S6;

[0009] S4. Analyze the extraction and separation section No. t-2: Calculate the fractional flow of each component in the aqueous phase drawn out from the left end of the extraction and separation section No. t-2 If t>4, then go to step S5; if t=4, then go to step S6;

[0010] S5. Analyze the extraction and separation sections t-3 to 2: Calculate the fractional flow of each component in the aqueous phase drawn from the left end of each extraction and separation section t-3 to 2.

[0011] S6. Analyze the No. 1 extraction and separation section: Calculate the split flow rates of the A1 and A2 components in the aqueous phase exiting the left outlet of the No. 1 extraction and separation section; Calculate the flow rate of the organic phase A1 component exiting the right outlet of the No. 1 extraction and separation section. Calculate the stripping agent flow rate W introduced from the right inlet of No. 1 extraction and separation section;

[0012] S7. Calculate the number of stages: Based on the extraction balance and material balance relationship of the materials in each extraction and separation section, start from the right end of each extraction and separation section and recursively calculate the number of extractor stages required for each separation section step by step.

[0013] Furthermore, the cascade extraction and separation equipment is composed of multiple stages of extraction tanks;

[0014] The organic phase loaded with mixed rare earth is introduced from the organic phase inlet at the left end of the cascade extraction and separation equipment. The loaded mixed rare earth is A t 、A t-1 ,…,A2,A1 components.

[0015] Furthermore, the extraction order of each component in a given P507 or P204 extractant system is A t t-1 <… <A2<A1;

[0016] In the mixed rare earth organic phase, each component A i (1≤i≤t) The fractional flow rate introduced into the extraction equipment is The total flow rate introduced into the extraction equipment is ​

[0017] Further, a stripping agent is introduced into the water phase inlet at the right end of the cascade extraction and separation device;

[0018] The aqueous phase outlet at the left end of the cascade extraction separation equipment flows out the t 、A t-1 , ..., A2, A1 component mixed rare earth aqueous phase, the organic phase outlet at the right end of the cascade extraction and separation equipment leads to the organic phase containing a single A1 component, and the aqueous phase outlets in the middle of the cascade extraction and separation equipment lead to A t-1 A t-2 ...A2A1、A t-2 A t-3 ...A2A1, ..., A3A2A1, A2A1.

[0019] Furthermore, the stripping agent is hydrochloric acid with a concentration of 1 to 7 mol / L.

[0020] Furthermore, in step S3, the total flow rate x of each component flowing out from the left end aqueous phase outlet of the t-1 extraction separation section is t-1 Calculate according to formula (1):

[0021]

[0022] In formula (1), Represents any two components A i and A j The separation coefficient between the two groups is calculated by the following formula (2):

[0023]

[0024] Furthermore, in step S3, the fractional flow of each component flowing out of the aqueous phase outlet at the left end of the t-1 extraction and separation section is By solving the following equations (3), we can get:

[0025]

[0026] Furthermore, in step S4, the fractional flow of each component in the aqueous phase drawn out from the left end of the t-2 extraction and separation section is Calculate according to formula (4):

[0027]

[0028] In formula (4), Represents the components A in the aqueous phase introduced into the t-1 extraction and separation section at the first stage on the left side of the t-2 extraction and separation section. i The split flow rate is obtained by solving the following equations (5):

[0029]

[0030] In formula (5), Represents the components A in the organic phase introduced into the t-2 extraction and separation section at the first stage on the right side of the t-1 extraction and separation section i The split flow is calculated according to the following formula (6):

[0031]

[0032] In formula (4), Represents the components A in the aqueous phase introduced from the second stage on the left end of the t-2 extraction and separation section to the first stage on the left end of the t-2 extraction and separation section. i The split flow is calculated according to the following formula (7):

[0033]

[0034] In formula (7), x t-2 ' represents the components A in the aqueous phase introduced from the second stage on the left end of the t-2 extraction and separation section to the first stage on the left end of the t-2 extraction and separation section. i The total flow rate is calculated as follows:

[0035]

[0036] Furthermore, in step S5, for the extraction and separation section No. t-3, the fractional flow of each component in the aqueous phase drawn from the left end is Calculate according to formula (9):

[0037]

[0038] In formula (9), Represents the components A in the aqueous phase introduced from the first stage at the left end of the t-3 extraction and separation section into the t-2 extraction and separation section i The split flow rate is obtained by solving the following equations (10):

[0039]

[0040] In formula (10), Represents the components A in the organic phase introduced into the t-3 extraction and separation section at the first stage on the right side of the t-2 extraction and separation section i The split flow is calculated according to the following formula (11):

[0041]

[0042] In formula (9), Represents the components A in the aqueous phase introduced from the second stage on the left end of the t-3 extraction and separation section to the first stage on the left end of the t-3 extraction and separation sectioni The split flow is calculated according to the following formula (12):

[0043]

[0044] In formula (12), x t-3 ' represents the components A in the aqueous phase introduced from the second stage on the left end of the t-3 extraction and separation section to the first stage on the left end of the t-3 extraction and separation section. i The total flow rate is calculated as follows:

[0045]

[0046] Furthermore, in the extraction and separation sections t-4 to 2, the fractional flow of each component in the aqueous phase drawn from the left end of each extraction and separation section is The fractional flow of each component in the aqueous phase drawn from the left end by the extraction and separation section t-3 The calculation method is the same.

[0047] Further, in step S6, the split flow of the two components in the aqueous phase drawn out from the left end outlet of the No. 1 extraction and separation section is Calculate according to formula (14):

[0048]

[0049] In formula (14), Represents the components A in the aqueous phase introduced from the first stage at the left end of the No. 1 extraction and separation section into the No. 2 extraction and separation section i The split flow rate is obtained by solving the following equations (15):

[0050]

[0051] In formula (15), Represents the components A in the organic phase introduced into the No. 1 extraction and separation section at the first stage on the right side of the No. 2 extraction and separation section i The split flow is calculated according to the following formula (16):

[0052]

[0053] In formula (14), Represents the components A in the aqueous phase introduced from the second stage at the left end of the No. 1 extraction and separation section to the first stage at the left end of the No. 1 extraction and separation section i The split flow is calculated according to the following formula (17):

[0054]

[0055] In formula (17), x1′ represents the components A in the aqueous phase introduced from the second stage at the left end of the first extraction and separation section into the first stage at the left end of the first extraction and separation section. i The total flow rate is calculated as follows:

[0056]

[0057] Furthermore, in step S6, the flow rate of the organic phase A1 component drawn out from the right end outlet of the No. 1 extraction and separation section is Calculate according to formula (19):

[0058]

[0059] Furthermore, in step S6, the stripping agent flow rate W introduced into the right end inlet of the No. 1 extraction and separation section is calculated according to the following formula (20):

[0060]

[0061] Further, in step S7, for the kth extraction and separation section among the t-1th to 1st extraction and separation sections, according to A k The purity requirement of rare earth products is combined with the material balance and extraction balance of the first stage at the right end of the kth extraction and separation section to obtain the corresponding extraction and separation section. The solution is obtained; the material transfer balance is then used to perform recursive calculations step by step until the relative deviation between the flow rate of each component in the organic phase and the flow rate of the loaded rare earth in the organic phase entering the kth extraction and separation section is less than the set value. The calculation is then completed. The number of recursive calculations step by step is the number of extractor stages required for the kth extraction and separation section.

[0062] Further, in step S7, for the t-1 extraction separation section, according to A t-1 Product rare earth purity requirements, set the right end of the organic phase outlet A t Component split flow Where ε=1-A t-1 Product rare earth purity;

[0063] According to the analysis of the extraction separation section t-1, the flow rate of each component at the organic phase outlet on the right end of the section is calculated.

[0064] Combining the material balance and extraction balance of the first stage (usually recorded as the n+m stage) on the right side of the t-1 extraction separation section, we can know that:

[0065]

[0066] Solving equation (21), we get a set of The organic phase flow rate of each component flowing out of the second stage at the right end of the t-1 extraction separation section is obtained by the following material transfer balance as follows:

[0067]

[0068] Repeat equations (21) and (22) step by step for recursive calculation until the relative deviation between the flow rate of each component in the organic phase and the flow rate of the rare earth loaded in the initial organic phase is less than the set value. The calculation is terminated. The number of step-by-step recursive calculations is the number of extractor stages required for the t-1 extraction and separation section.

[0069] The beneficial effects of the present invention are as follows: the design method of the segmented stripping linkage extraction process of the mixed rare earth loaded organic phase provided by the present invention comprises the following steps: according to the component number t (t is an integer ≥2) of the mixed rare earth loaded organic phase, designing the process framework of the cascade extraction and separation equipment, determining the aqueous phase outlet, organic phase outlet and components of the cascade extraction; dividing the cascade extraction and separation equipment into t-1 extraction and separation sections, with an extraction and separation section between every two outlets, and marking them as extraction and separation sections 1, 2, ..., t-2, and t-1 from right to left; calculating the total flow rate of each component flowing out of the aqueous phase outlet at the left end of the t-1 extraction and separation section, and calculating the total flow rate of the components flowing out of the t-1 extraction and separation section. Calculate the fractional flow rate of each component flowing out of the aqueous phase outlet at the left end of the separation section; calculate the fractional flow rate of each component in the aqueous phase drawn out from the left end of the extraction and separation section No. t-2; calculate the fractional flow rate of each component in the aqueous phase drawn out from the left end of each extraction and separation section in extraction and separation sections No. t-3 to No. 2; calculate the fractional flow rate of two components in the aqueous phase drawn out from the left end outlet of extraction and separation section No. 1; calculate the flow rate of organic phase A1 component drawn out from the right end outlet of extraction and separation section No. 1; calculate the flow rate of the back-extractant introduced from the right end inlet of extraction and separation section No. 1; finally, based on the extraction balance and material balance relationship of the materials in each extraction and separation section, recursively calculate the number of extractor stages required for each separation section, starting from the right end of each extraction and separation section. The present invention utilizes a segmented stripping linkage extraction and separation process for the organic phase of mixed rare earths loaded with rare earth sulfate. By rationally designing the outlet and outlet flow rates, the process achieves the transformation goal while maximizing the separation work of the stripping agent without increasing the amount of stripping agent used. The mixed rare earths loaded in the organic phase are crudely separated, allowing each component to be enriched in different outlet aqueous phases, and a single pure product containing the most easily extractable component can be obtained. Each export product can be sold as an enriched product or a single pure product. The enriched product can also reduce the consumption of chemical reagents such as acids and alkalis in subsequent extraction and separation steps, saving production costs and reducing the amount of saline wastewater generated. The process design method provided by the present invention can optimize the segmented stripping process for the organic phase loaded with mixed rare earths, making the maximum use of the separation work of the stripping agent while approaching the theoretical minimum stripping agent consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1This is a schematic flow chart of a segmented stripping linkage extraction process for a mixed rare earth loaded organic phase according to an embodiment of the present invention;

[0071] Figure 2 This is a schematic diagram of the process of a segmented stripping linkage extraction process of a mixed rare earth loaded organic phase according to an embodiment of the present invention;

[0072] Figure 3 This is a schematic diagram of the Baotou mixed rare earth sulfuric acid roasting water leachate treatment process, and a schematic diagram of the material inlet and outlet in each extraction and separation section, designed using the design method of the segmented stripping linkage extraction process of the mixed rare earth organic phase in an embodiment of the present invention. DETAILED DESCRIPTION

[0073] The technical solutions in the embodiments of the present invention will be further clearly and completely described below in conjunction with the drawings and examples. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0074] It should be noted that, in the description of the embodiments of the present invention, terms such as "horizontal", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0075] In the traditional full extraction transformation process using saponified P507 (or P204) extractant, hydrochloric acid is used for full stripping after full extraction of rare earths, and the separation work of the stripping agent is not utilized. The goal of the present invention is to use a segmented stripping linkage extraction and separation process for the organic phase of the mixed rare earth loaded by the full extraction of rare earth sulfate, and through optimized design, to achieve the purpose of transformation to rare earth chloride while maximizing the separation work of the stripping agent to perform coarse separation of the mixed rare earth loaded by the organic phase. The aqueous phases enriched with different components obtained at different outlets can be directly sold as enriched products to meet market demand, and the consumption demand for chemical reagents, acids and alkalis, is also reduced in the subsequent extraction and separation process, thereby reducing separation costs and the amount of salt-containing wastewater generated.

[0076] This embodiment provides a segmented stripping linkage extraction process for a mixed rare earth organic phase and an optimization design method thereof, wherein the segmented stripping linkage extraction process for a mixed rare earth organic phase is as follows: Figure 1As shown, an organic phase loaded with rare earth mixture of components A t , A t-1 , …, A2, A1 is introduced from the organic phase inlet at the left end of the cascade extraction separation equipment composed of multiple extraction cells. The extraction sequence of each component in the given P507 (or P204) extractant system is A t < A t-1 < … < A2 < A1, that is, A1 is the most easily extracted component and A t is the most difficult to extract component; in the organic phase loaded with rare earth mixture, the split flow rate of component A i (1 ≤ i ≤ t) introduced into the extraction equipment is and the total flow rate is An stripping agent is introduced from the aqueous phase inlet at the right end of the cascade extraction separation equipment. An aqueous phase containing rare earth mixture of components A t , A t-1 , …, A2, A1 flows out from the aqueous phase outlet at the left end of the cascade extraction separation equipment, and an organic phase containing a single A1 component is led out from the organic phase outlet at the right end. The aqueous phases at the intermediate outlets are led out from left to right as A t- 1A t-2 ... A2A1, A t-2 A t-3 ... A2A1, …, A3A2A1, A2A1. The split flow rates of the rare earth components in the organic phase loaded introduced from the left end of the cascade extraction separation equipment o and the total flow rate f

[0077] are known process parameters. The flow rate of the stripping agent introduced from the right end, and the split flow rates and total flow rates of each component output at each outlet need to be calculated by the optimization design method provided in this patent. Figure 1-2 As

[0078] shown, a design method for a segmented stripping linkage extraction process of an organic phase loaded with rare earth mixture provided by an embodiment of the present invention includes the following steps:

[0079] Specifically, as Figure 1 shown, the cascade extraction separation equipment is composed of multiple extraction cells; the organic phase loaded with rare earth mixture is introduced from the organic phase inlet at the left end of the cascade extraction separation equipment, and the loaded rare earth mixture is A t , A t-1 , …, A2, A1 components.

[0080] Among them, the extraction sequence of each component in the given P507 (or P204) extractant system is A t < At-1 <… <A2 < A1; The split flow rate of each component A i (1 ≤ i ≤ t) introduced into the extraction equipment is The total flow rate introduced into the extraction equipment is

[0081] An anti-extraction agent is introduced at the aqueous phase inlet at the right end of the cascade extraction separation equipment. An aqueous phase containing mixed rare earths of components A t 、A t-1 、…、A2、A1 flows out from the aqueous phase outlet at the left end of the cascade extraction separation equipment. An organic phase containing a single A1 component is led out from the organic phase outlet at the right end of the cascade extraction separation equipment. Each aqueous phase outlet in the middle of the cascade extraction separation equipment leads out A t-1 A t-2 ... A2A1、A t-2 A t-3 ... A2A1、…、A3A2A1、A2A1.

[0082] Specifically, the extractant in the loaded mixed rare earth organic phase is P507 or P204, and the anti-extraction agent is hydrochloric acid.

[0083] Optionally, the anti-extraction agent uses hydrochloric acid with a concentration of 1 - 7 mol / L.

[0084] S2. Divide Figure 1 the cascade extraction separation equipment described in into t - 1 extraction separation sections. Each section between two outlets is an extraction separation section, which is sequentially marked as 1, 2, …, t - 2, t - 1 extraction separation sections from right to left, as Figure 2 shown; if t > 2, then proceed to step S3; if t = 2, then proceed to step S6;

[0085] S3. First, analyze the (t - 1)-th extraction separation section. According to the split flow rate of each rare earth component introduced into the loaded organic phase from the left end of the cascade extraction separation equipment o and the total flow rate f t-1 , calculate the total flow rate x of each component flowing out from the left end aqueous phase outlet of the (t - 1)-th extraction separation section. Calculate the split flow rate

[0086] of each component flowing out from the left end aqueous phase outlet of the (t - 1)-th extraction separation section. If t > 3, then proceed to step S4; if t = 3, then proceed to step S6; t-1 Specifically, analyze the (t - 1)-th extraction separation section. The total flow rate x

[0087]

[0088] In formula (1), Represents A between any two groups i and A j The separation coefficient between the two groups is calculated by the following formula (2):

[0089]

[0090] The fractional flow of each component flowing out of the left end aqueous phase outlet of the t-1 extraction separation section By solving the following equations (3), we can get:

[0091]

[0092] S4. Analyze the extraction and separation section No. t-2 and calculate the fractional flow of each component in the first stage of the aqueous phase drawn out from the left end of the extraction and separation section No. t-2. If t>4, then go to step S5; if t=4, then go to step S6;

[0093] Specifically, the fractional flow of each component in the aqueous phase drawn out from the left end of the t-2 extraction separation section Calculate according to formula (4):

[0094]

[0095] In formula (4), Represents the components A in the aqueous phase introduced from the first stage at the left end of the t-2 extraction and separation section into the t-1 extraction and separation section i The split flow rate is obtained by solving the following equations (5):

[0096]

[0097] In formula (5), Represents the components A in the organic phase introduced into the t-2 extraction and separation section at the first stage on the right side of the t-1 extraction and separation section i The split flow is calculated according to the following formula (6):

[0098]

[0099] In formula (4), Represents the components A in the aqueous phase introduced from the second stage on the left end of the t-2 extraction and separation section to the first stage on the left end of the t-2 extraction and separation section. i The split flow is calculated according to the following formula (7):

[0100]

[0101] In formula (7), x t-2' represents the components A in the aqueous phase introduced from the second stage on the left end of the t-2 extraction and separation section to the first stage on the left end of the t-2 extraction and separation section. i The total flow rate is calculated as follows:

[0102]

[0103] S5. Analyze the extraction and separation sections t-3 to 2, and calculate the fractional flow of each component in the aqueous phase drawn from the left end of each extraction and separation section t-3 to 2.

[0104] Specifically, for the t-3 extraction and separation section, the fractional flow of each component in the aqueous phase drawn out from the left end of the t-3 extraction and separation section is Calculate according to formula (9):

[0105]

[0106] In formula (9), Represents the components A in the aqueous phase introduced from the first stage at the left end of the t-3 extraction and separation section into the t-2 extraction and separation section i The split flow rate is obtained by solving the following equations (10):

[0107]

[0108] In formula (10), Represents the components A in the organic phase introduced into the t-3 extraction and separation section at the first stage on the right side of the t-2 extraction and separation section i The split flow is calculated according to the following formula (11):

[0109]

[0110] In formula (9), Represents the components A in the aqueous phase introduced from the second stage on the left end of the t-3 extraction and separation section to the first stage on the left end of the t-3 extraction and separation section i The split flow is calculated according to the following formula (12):

[0111]

[0112] In formula (12), x t-3 ' represents the components A in the aqueous phase introduced from the second stage on the left end of the t-3 extraction and separation section to the first stage on the left end of the t-3 extraction and separation section. i The total flow rate is calculated as follows:

[0113]

[0114] In the extraction and separation sections No. t-4 to No. 2, the fractional flow rate of each component in the aqueous phase drawn from the left end of each extraction and separation section The fractional flow of each component in the aqueous phase drawn from the left end by the extraction and separation section t-3 The calculation method is the same.

[0115] S6. Finally, analyze the No. 1 extraction and separation section and calculate the split flow rates of the two components A1 and A2 in the aqueous phase drawn out from the left outlet of the No. 1 extraction and separation section; calculate the flow rate of the organic phase component A1 drawn out from the right outlet of the No. 1 extraction and separation section. Calculate the stripping agent flow rate W introduced from the right inlet of No. 1 extraction and separation section;

[0116] Specifically, the split flow of the two components in the aqueous phase drawn out from the left end outlet of the No. 1 extraction separation section is Calculate according to formula (14):

[0117]

[0118] In formula (14), Represents the components A in the aqueous phase introduced from the first stage at the left end of the No. 1 extraction and separation section into the No. 2 extraction and separation section i The split flow is obtained by solving the following equation group (15):

[0119]

[0120] In formula (15), Represents the components A in the organic phase introduced into the No. 1 extraction and separation section at the first stage on the right side of the No. 2 extraction and separation section i The split flow is calculated according to the following formula (16):

[0121]

[0122] In formula (14), Represents the components A in the aqueous phase introduced from the second stage at the left end of the No. 1 extraction and separation section into the first stage at the left end of the No. 1 extraction and separation section i The split flow is calculated according to the following formula (17):

[0123]

[0124] In formula (17), x1′ represents the components A in the aqueous phase introduced from the second stage at the left end of the first extraction and separation section into the first stage at the left end of the first extraction and separation section. i The total flow rate is calculated as follows:

[0125]

[0126] The organic phase drawn out from the right end outlet of No. 1 extraction separation section contains only a single A1 component, and its flow rate is Calculate according to formula (19):

[0127]

[0128] The stripping agent flow rate W introduced from the right inlet of the No. 1 extraction and separation section is calculated according to the following formula (20):

[0129]

[0130] S7. Calculate the series: According to Figure 2 The extraction balance and material balance relationship of the materials in each extraction and separation section divided in the figure is calculated recursively step by step from the right end of each extraction and separation section to calculate the number of extractor stages required for each separation section.

[0131] Specifically, for the kth extraction and separation section among the t-1th to 1st extraction and separation sections, according to A k The purity requirement of rare earth products is combined with the material balance and extraction balance of the first stage at the right end of the kth extraction and separation section to obtain the corresponding extraction and separation section. The solution is obtained, and then the material transfer balance is recursively calculated step by step until the relative deviation between the flow rate of each component in the organic phase and the flow rate of the loaded rare earth in the organic phase entering the kth extraction separation section is less than the set value (such as 1×10 -4 ), the calculation ends, and the number of recursive calculations step by step is the number of extractor stages required for the kth extraction and separation section.

[0132] Specifically, for the extraction and separation section No. t-1, the components of the left organic phase inlet and the water phase outlet are both A t A t-1 ...A2A1, the components of the right organic phase outlet and the water phase inlet are both A t-1 ...A2A1. In the actual separation process, the product has a certain purity, and the A t Component split flow where ε is based on A t-1 The purity requirement of the rare earth product is determined, ε=1-A t-1 Product rare earth purity. In a specific embodiment, the final requirement is A t-1 The purity of the rare earth product needs to reach 99.99%, so ε = 0.0001.

[0133] The flow rate of each component at the organic phase outlet on the right side of the section can be calculated by analyzing the extraction and separation section t-1. As shown in formula (6), and set ε=1-A t-1The purity of the rare earth products can be determined from the material balance and extraction balance of the first stage (usually recorded as the n+m stage) at the right end of the t-1 extraction and separation section:

[0134]

[0135] Solving the above system of equations, we can get a set of The organic phase flow rate of each component flowing out of the second stage (usually recorded as the n+m-1 stage) at the right end of the t-1 extraction separation section is obtained by the following material transfer balance: as follows:

[0136]

[0137] Repeat equations (21) and (22) step by step to perform recursive calculations until the relative deviation between the flow rate of each component in the organic phase and the flow rate of the rare earth loaded in the initial organic phase is less than the set value (e.g. 1×10 -4 ), the calculation ends. The number of recursive calculations is the minimum number of extractor stages required for the extraction and separation stage (t-1). Using this minimum number of extractor stages fully utilizes the stripping agent's separation work, maximizing its separation capacity (even increasing the number of extractor stages does not improve the separation effect).

[0138] The segmented stripping and linked extraction process of the mixed rare earth loaded organic phase provided in this embodiment can fully utilize the separation work of the stripping agent (i.e., the separation capacity of the stripping agent), perform rough separation during the stripping process of the mixed rare earth loaded organic phase, so that each component is enriched in the aqueous phase drawn out from different outlets, and obtain a single pure product of the most easily extractable component; the obtained rough separated product can be sold as an enriched product, and can also reduce acid and alkali consumption in subsequent further extraction and separation steps, save production costs, and reduce the amount of salt-containing wastewater generated; at the same time, the process design method provided by the present invention can achieve the optimization of the segmented stripping process of the mixed rare earth loaded organic phase, and make the most full use of the separation work of the stripping agent while approaching the theoretical minimum stripping agent consumption.

[0139] The specific embodiments of the present invention are further described below through examples.

[0140] Example 1: Treatment of a batch of Baotou mixed rare earth sulfuric acid roasted water extract using the above-mentioned design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earth

[0141] The Baotou mixed rare earth sulfuric acid roasted water extract was fully extracted with saponified P507 extractant, and the organic phase was loaded with mixed rare earths, which mainly contained four components: La, Ce, Pr, and Nd. The total amount of medium and heavy rare earth components such as Sm, Eu, and Gd was only about 2%, and they were considered together with Nd in the calculation.

[0142] In this embodiment, the stripping agent is hydrochloric acid with a concentration of 5 to 5.5 mol / L.

[0143] The organic phase loaded with mixed rare earths is subjected to a staged stripping method designed in this embodiment; the three aqueous phase outlets lead out the aqueous phases containing LaCePrNd, CePrNd, and PrNd in sequence from left to right; the organic phase outlet on the far right leads out the organic phase containing a single Nd product; the stripping agent is introduced from the far right. The flow rate of the four components La, Ce, Pr, and Nd loaded in the initial organic phase is f La,o 、f Ce,o 、f Pr,o 、f Nd,o The separation coefficients between the components are shown in Table 1 below.

[0144] Table 1 Flow rates of the four components loaded in the initial organic phase and the separation coefficients between the components

[0145]

[0146] The staged stripping process designed according to the method provided in this embodiment and the required number of stages for each extraction and separation stage are as follows: Figure 3 As shown, the specific steps include:

[0147] S11, according to the fractional flow rate f of each rare earth component in the loaded organic phase introduced from the left end of the cascade extraction separation device La,o 、f Ce,o 、f Pr,o 、f Nd,o Assuming a total flow rate of 100 L, the total flow rate x3 of each component flowing out of the left end water phase outlet of the No. 3 extraction and separation section is calculated according to formula (1) to (2). The fractional flow rate of each component flowing out of the left end water phase outlet of the No. 3 extraction and separation section is calculated according to formula (3).

[0148] S12. Calculate the fractional flow of each component in the aqueous phase drawn from the left end of the No. 2 extraction separation section according to formulas (4) to (8):

[0149] S13. Calculate the flow rate of the two components in the aqueous phase drawn out from the left end outlet of the No. 1 extraction and separation section according to formula (14) to (18); calculate the flow rate of the organic phase A1 component drawn out from the right end outlet of the No. 1 extraction and separation section according to formula (19) Calculate the stripping agent flow rate W introduced from the right inlet of No. 1 extraction and separation section according to formula (20);

[0150] S14. Calculate the series: According to Figure 3 The extraction balance and material balance relationship of the materials in each extraction and separation section divided in the figure is calculated recursively step by step from the right end of each extraction and separation section to calculate the number of extractor stages required for each separation section.

[0151] For the extraction separation section No. 3, the components of the left organic phase inlet and the aqueous phase outlet are both LaCePrNd, and the components of the right organic phase inlet and the aqueous phase inlet are both CePrNd. Set the fractional flow rate y of the component La in the right organic phase outlet La,n+m =ε·y Ce,n+m , where ε is determined according to the rare earth purity requirement of the Ce product, ε = 1 - rare earth purity of the Ce product. In this embodiment, the ultimate requirement is that the rare earth purity of the Ce product must reach 99.99%, so ε = 0.0001. At the same time, based on the analysis of the No. 3 extraction and separation section, the flow rate of each component at the organic phase outlet at the right end of the No. 3 extraction and separation section can be calculated as shown in formula (6): Combining the material balance of the first stage at the right end of the No. 3 extraction and separation section and the extraction balance formula (21), the flow rate of each component in the organic phase of the first stage at the right end of the No. 3 extraction and separation section is obtained: Combined with the material transfer balance of formula (22), the flow rate of each component in the organic phase of the second stage at the right end of the No. 3 extraction separation section is obtained Repeat equations (21) and (22) step by step to perform recursive calculations until the relative deviation between the flow rate of each component in the organic phase and the flow rate of the rare earth loaded in the initial organic phase is less than the set value (1×10 -4 ), the calculation ends, and the number of recursive calculations step by step is 18, which means the minimum number of extractor stages required for the No. 3 extraction and separation section is 18.

[0152] Using the same method, we can recursively calculate step by step that the number of extractor stages required for the No. 2 extraction and separation section is 28, and the number of extractor stages required for the No. 1 extraction and separation section is 58.

[0153] Calculations show that at the outlet x3 of the third extraction and separation section, the La component is enriched from the initial 27.90% to 76.6%; at the outlet x2 of the second extraction and separation section, the Ce component is enriched from the initial 50.62% to 89.76%; at the outlet x1 of the first extraction and separation section, the Pr component is enriched from the initial 4.87% to 76.13%; 69.87% of the most easily extractable component Nd flows out of the rightmost organic phase outlet in the form of a single product (purity > 99.99%); the stripping agent flow rate W input at the rightmost end is 88.3948, the stripping agent flow rate required for stripping Nd in the obtained organic phase is 11.6052, and the total stripping agent flow rate is 100.0000L. In the conventional process, the amount of stripping agent used is also 100.0000, but only a mixed liquid of all components is obtained at the leftmost outlet, with no separation effect. However, in the process designed by the present invention, without increasing the amount of stripping agent used, the components are enriched separately at different outlets, and the stripping agent's separation work is fully utilized by rationally designing the outlet and outlet flow rates.

[0154] The methods described herein are not limited to the specific embodiments described. The above embodiments are merely illustrative of the present invention, and the present invention may also be implemented in other specific ways or in other specific forms without departing from the gist or essential characteristics of the present invention. Therefore, the embodiments described herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is to be determined by the appended claims, and any variations that are equivalent to the intent and scope of the claims are intended to be within the scope of the present invention.

Claims

1. A design method for a segmented stripping linkage extraction process for a mixed rare earth organic phase, characterized in that: The method comprises the following steps: S1. Design the process framework of the cascade extraction and separation equipment according to the component number t (t is an integer ≥ 2) of the organic phase loaded with mixed rare earths, and determine the aqueous phase outlet, organic phase outlet and components of the cascade extraction; S2. Divide the cascade extraction and separation equipment into t-1 extraction and separation sections, with each section between two outlets being an extraction and separation section, and mark them as extraction and separation sections 1, 2, ..., t-2, and t-1 from right to left; if t>2, proceed to step S3; if t=2, proceed to step S6; S3. Analysis of the extraction and separation section t-1: Based on the fractional flow of each rare earth component in the loaded organic phase introduced from the left end of the cascade extraction and separation equipment And the total flow f o Calculate the total flow rate x of each component flowing out of the left end water phase outlet of the t-1 extraction separation section t-1 , calculate the fractional flow rate of each component flowing out of the left end water phase outlet of the t-1 extraction separation section If t>3, then go to step S4; if t=3, then go to step S6; S4. Analyze the extraction and separation section No. t-2: Calculate the fractional flow of each component in the aqueous phase drawn out from the left end of the extraction and separation section No. t-2 If t>4, then go to step S5; if t=4, then go to step S6; S5. Analyze the extraction and separation sections t-3 to 2: Calculate the fractional flow of each component in the aqueous phase drawn from the left end of each extraction and separation section t-3 to 2. S6. Analyze the No. 1 extraction and separation section: calculate the split flow rates of components A1 and A2 in the aqueous phase exiting the left end outlet of the No. 1 extraction and separation section; Calculate the flow rate of the organic phase A1 component drawn out from the right end outlet of the No. 1 extraction separation section Calculate the stripping agent flow rate W introduced from the right inlet of No. 1 extraction and separation section; S7. Calculate the number of stages: Based on the extraction balance and material balance relationship of the materials in each extraction and separation section, start from the right end of each extraction and separation section and recursively calculate the number of extractor stages required for each separation section step by step.

2. The design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earths according to claim 1 is characterized in that: The cascade extraction and separation equipment is composed of multiple stages of extraction tanks; The organic phase loaded with mixed rare earth is introduced from the organic phase inlet at the left end of the cascade extraction and separation equipment. The loaded mixed rare earth is A t 、A t-1 ,…,A2,A1 components.

3. The design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earths according to claim 2 is characterized in that: The extraction order of each component in a given P507 or P204 extractant system is A t t-1 <… <A2<A1;​ In the mixed rare earth organic phase, each component A i (1≤i≤t) The fractional flow rate introduced into the extraction equipment is The total flow rate introduced into the extraction equipment is 4. The design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earths according to claim 2 is characterized in that: The stripping agent is introduced into the water phase inlet at the right end of the cascade extraction separation device; the water phase containing A flows out from the water phase outlet at the left end of the cascade extraction separation device. t 、A t-1 , ..., A2, A1 component mixed rare earth aqueous phase, the organic phase outlet at the right end of the cascade extraction and separation equipment leads to the organic phase containing a single A1 component, and the aqueous phase outlets in the middle of the cascade extraction and separation equipment from left to right lead to A t-1 A t-2 ...A2A1、A t-2 A t-3 ...A2A1, ..., A3A2A1, A2A1.

5. The design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earths according to claim 4 is characterized in that: The stripping agent is hydrochloric acid with a concentration of 1 to 7 mol / L.

6. The design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earths according to claim 1 is characterized in that: In step S3, the total flow rate x of each component flowing out from the left end water phase outlet of the t-1 extraction separation section is t-1 Calculate according to formula (1): In formula (1), Represents any two components A i and A j The separation coefficient between the two groups is calculated by the following formula (2):

7. The design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earths according to claim 1 is characterized in that: In step S3, the fractional flow of each component flowing out from the left end aqueous phase outlet of the t-1 extraction separation section is By solving the following equations (3), we can get:

8. The design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earths according to claim 1 is characterized in that: In step S4, the fractional flow of each component in the aqueous phase drawn out from the left end of the t-2 extraction and separation section is Calculate according to formula (4): In formula (4), Represents the components A in the aqueous phase introduced into the t-1 extraction and separation section at the first stage on the left side of the t-2 extraction and separation section. i The split flow rate is obtained by solving the following equations (5): In formula (5), Represents the components A in the organic phase introduced into the t-2 extraction and separation section at the first stage on the right side of the t-1 extraction and separation section i The split flow is calculated according to the following formula (6): In formula (4), Represents the components A in the aqueous phase introduced from the second stage on the left end of the t-2 extraction and separation section to the first stage on the left end of the t-2 extraction and separation section. i The split flow is calculated according to the following formula (7): In formula (7), x t-2 ′ Represents the components A in the aqueous phase introduced from the second stage on the left end of the t-2 extraction and separation section to the first stage on the left end of the t-2 extraction and separation section. i The total flow rate is calculated as follows:

9. The design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earths according to claim 1, characterized in that: In step S5, for the extraction and separation section No. t-3, the fractional flow of each component in the aqueous phase drawn from the left end is Calculate according to formula (9): In formula (9), Represents the components A in the aqueous phase introduced from the first stage at the left end of the t-3 extraction and separation section into the t-2 extraction and separation section i The split flow rate is obtained by solving the following equations (10): In formula (10), Represents the components A in the organic phase introduced into the t-3 extraction and separation section at the first stage on the right side of the t-2 extraction and separation section i The split flow is calculated according to the following formula (11): In formula (9), Represents the components A in the aqueous phase introduced from the second stage on the left end of the t-3 extraction and separation section to the first stage on the left end of the t-3 extraction and separation section i The split flow is calculated according to the following formula (12): In formula (12), x t-3 ′ Represents the components A in the aqueous phase introduced from the second stage on the left end of the t-3 extraction and separation section to the first stage on the left end of the t-3 extraction and separation section i The total flow rate is calculated as follows:

10. The design method of the segmented stripping linkage extraction process of the mixed rare earth loaded organic phase according to claim 9, characterized in that: In the extraction and separation sections No. t-4 to No. 2, the fractional flow rate of each component in the aqueous phase drawn from the left end of each extraction and separation section The fractional flow of each component in the aqueous phase drawn from the left end by the extraction and separation section t-3 The calculation method is the same.

11. The method for designing a segmented stripping linkage extraction process for a mixed rare earth loaded organic phase according to any one of claims 1 to 10, characterized in that: In step S6, the split flow of the two components in the aqueous phase drawn out from the left end outlet of the No. 1 extraction and separation section is Calculate according to formula (14): In formula (14), Represents the components A in the aqueous phase introduced from the first stage at the left end of the No. 1 extraction and separation section into the No. 2 extraction and separation section i The split flow rate is obtained by solving the following equations (15): In formula (15), Represents the components A in the organic phase introduced into the No. 1 extraction and separation section at the first stage on the right side of the No. 2 extraction and separation section i The split flow is calculated according to the following formula (16): In formula (14), Represents the components A in the aqueous phase introduced from the second stage at the left end of the No. 1 extraction and separation section into the first stage at the left end of the No. 1 extraction and separation section i The split flow is calculated according to the following formula (17): In formula (17), x1 ′ Represents the components A in the aqueous phase introduced from the second stage at the left end of the No. 1 extraction and separation section into the first stage at the left end of the No. 1 extraction and separation section i The total flow rate is calculated as follows:

12. The design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earths according to claim 11, characterized in that: In step S6, the flow rate of the organic phase A1 component drawn out from the right end outlet of the No. 1 extraction and separation section is Calculate according to formula (19):

13. The design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earths according to claim 11, characterized in that: In step S6, the stripping agent flow rate W introduced into the right end inlet of the first extraction and separation section is calculated according to the following formula (20):

14. The design method of the segmented stripping linkage extraction process of the organic phase loaded with mixed rare earths according to claim 11, characterized in that: In step S7, for the kth extraction and separation section among the t-1th to 1st extraction and separation sections, according to A k The purity requirement of rare earth products is combined with the material balance and extraction balance of the first stage at the right end of the kth extraction and separation section to obtain the corresponding extraction and separation section. The solution is obtained; the material transfer balance is then used to perform recursive calculations step by step until the relative deviation between the flow rate of each component in the organic phase and the flow rate of the loaded rare earth in the organic phase entering the kth extraction and separation section is less than the set value. The calculation is then completed. The number of recursive calculations step by step is the number of extractor stages required for the kth extraction and separation section.

15. The design method of the segmented stripping linkage extraction process of the mixed rare earth loaded organic phase according to claim 14, characterized in that: In step S7, for the t-1 extraction separation section, according to A t-1 Product rare earth purity requirements, set the right end of the organic phase outlet A t Component split flow Where ε=1-A t-1 Product rare earth purity; According to the analysis of the extraction separation section t-1, the flow rate of each component at the organic phase outlet on the right end of the section is calculated. Combining the material balance and extraction balance of the first stage at the right end of the t-1 extraction separation section, we can know that: Solving equation (21), we get a set of The organic phase flow rate of each component flowing out of the second stage at the right end of the t-1 extraction separation section is obtained by the following material transfer balance as follows: Repeat equations (21) and (22) step by step for recursive calculation until the relative deviation between the flow rate of each component in the organic phase and the flow rate of the rare earth loaded in the initial organic phase is less than the set value. The calculation is terminated. The number of step-by-step recursive calculations is the number of extractor stages required for the t-1 extraction and separation section.

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