A fixed bed u-tower rinse process

Abstract

The present application belongs to the technical field of in-situ leaching uranium mining, and particularly relates to a fixed bed U-shaped tower leaching process. The present application adopts a process of three-tower moving bed parallel adsorption-one-tower saturated resin rinsing-four-tower fixed bed series leaching-two-tower fixed bed transformation and post-leaching qualified liquid hydrochloric acid acidification and alkali precipitation, and slurry plate frame after the "111" product process. Under the premise of basically unchanged leaching agent components, the leaching efficiency is improved, the leaching agent consumption is reduced, and the uranium concentration in the qualified liquid is improved, so as to reduce the unit consumption of alkali in the qualified liquid precipitation process.

Description

Technical Field

[0001] The invention belongs to the technical field of in-situ leaching of uranium, and in particular relates to a fixed-bed U-shaped tower leaching process. Background Art

[0002] The uranium concentration of the leachate from in-situ leaching uranium mines is low and the flow rate is large, and ion exchange is generally used to extract uranium.

[0003] After the resin is saturated, an appropriate eluent is needed to remove the uranium from the resin. Leaching is the reverse process of adsorption. Commonly used eluents for acid in-situ leaching include acidic chloride solutions (NaCl-H2SO4, NH4Cl-H2SO4), acidic nitrate solutions (HNO3-NaNO3, HNO3-NH4NO3, H2SO4-NH4NO3, H2SO4-NaNO3), dilute nitric acid, and dilute sulfuric acid. Commonly used eluents for alkaline in-situ leaching include NaCl-NaHCO3, NaCl-Na2CO3, and NaNO3-NaHCO3. Domestic acid mines generally use acidic nitrate leaching, while alkaline or neutral mines generally use salt with a small amount of sodium bicarbonate added. The American eluent is NaCl+Na2CO3, of which the Highland mine uses 1mol / LNaCl+0.4mol / LNa2CO3 and adopts hot water elution process, while the Crow Butte mine uses 1.1mol / LNaCl+0.24mol / LNa2CO3.

[0004] To increase the concentration of uranium-saturated resin-eluted uranium, saturated resin re-adsorption technology is commonly used in acid-based in-situ leaching processes to further enhance the uranium capacity of the saturated resin and the uranium concentration of the eluent. This technology requires numerous towers (eight in total: one saturated re-adsorption tower, one recovery adsorption tower, three leaching towers, and three transformation towers). The resin is frequently reloaded (every 1-3 hours per week, eight times per week), resulting in significant resin wear and consumption. To mitigate these shortcomings, relevant research institutions have developed a U-shaped tower elution technology. This integrates multiple processes (elution, re-adsorption, recovery adsorption, and partial transformation and rinsing) within a single U-shaped tower. This not only reduces resin wear but also cleverly utilizes density flow to improve mass transfer efficiency, potentially doubling the uranium concentration of the eluent. However, key technologies such as the relative transport of solid and liquid phases within the U-shaped tower, the liquid distribution method, and the corresponding parameter control have not been publicly disclosed. Furthermore, the tower suffers from significant drawbacks, such as its large size, difficulty in maintenance, and the time required to re-establish the resin gradient once it is disrupted.

[0005] The saturated resin uranium capacity of the alkali method or neutral leaching uranium is higher than that of the acid method, and it is generally considered that the saturated resin does not need to be resorbed, and is usually designed as a fixed bed three-tower series upper liquid leaching. In the prior art, CO2+O2 neutral leaching is generally used, and the design process is: three-tower moving bed parallel adsorption-three-tower fixed bed series leaching-two-tower fixed bed transformation and leaching qualified liquid hydrochloric acid acidification and then alkali precipitation, and the slurry is framed and then "111" product is obtained. By using the process, the uranium concentration of the leaching qualified liquid is about 35g / L. How to improve the leaching efficiency and reduce the leaching agent consumption under the premise that the composition of the leaching agent is basically unchanged, and how to improve the uranium concentration in the leaching qualified liquid to reduce the unit consumption of alkali in the precipitation process of the qualified liquid, are technical problems urgently to be solved in the field. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a fixed bed U-shaped tower leaching process, which improves the leaching efficiency and reduces the leaching agent consumption under the premise that the composition of the leaching agent is basically unchanged, and improves the uranium concentration in the leaching qualified liquid to reduce the unit consumption of alkali in the precipitation process of the qualified liquid.

[0007] The technical solution of the present application is as follows:

[0008] A fixed bed U-shaped tower leaching process adopts three-tower moving bed parallel adsorption-one-tower saturated resin rinsing-four-tower fixed bed series leaching-two-tower fixed bed transformation and leaching qualified liquid hydrochloric acid acidification and then alkali precipitation-slurry framing and then "111" product design;

[0009] The four-tower fixed bed series leaching process includes the following saturated resorption process and leaching process.

[0010] Step S1

[0011] For the Nth saturated resorption process, the four saturated resin towers are (n+1) # tower, (n+2) # tower, (n+3) # tower and (n+4) # tower, wherein n=N-1; the leaching agent flows into the top of the (n+1) # tower in the form of upward flow, and the liquid flows out from the bottom; then the leaching agent flows into the top of the (n+2) # tower in the form of upward flow, and the liquid flows out from the bottom; then the leaching agent flows into the bottom of the (n+3) # tower in the form of downward flow, and the liquid flows out from the top; then the leaching agent flows into the bottom of the (n+4) # tower in the form of downward flow, and the liquid flows out from the top; the liquid out of the (n+4) # tower is the resorption tail liquid with low uranium concentration and low chloride ion concentration;

[0012] When the uranium concentration of the liquid out of the (n+4) # tower is higher than Xg / L, the (n+4) # tower is disconnected, and the (n+1) # tower, the (n+2) # tower and the (n+3) # tower enter the leaching process.

[0013] Step S2

[0014] In the elution process, the liquid inlet mode of the (n+1)th tower and the (n+2)th tower is kept unchanged, and the liquid inlet mode of the (n+3)th tower is changed from lower liquid inlet to upper liquid inlet, i.e. the effluent of the (n+2)th tower flows into the top of the (n+3)th tower, and the three-tower series elution is carried out, and the effluent of the (n+3)th tower flows into the qualified liquid tank;

[0015] Step S3

[0016] When the uranium concentration of the effluent of the (n+1)th tower is lower than Y g / L, the (n+1)th tower is cut off for transformation, at the same time, the effluent of the (n+3)th tower no longer flows into the qualified liquid tank, but flows into the (n+4)th tower from the bottom in the lower liquid inlet mode, and the effluent of the (n+4)th tower flows into the bottom of the newly connected saturated resin tower, i.e. the (n+5)th tower, in the lower liquid inlet mode, at this time, the four saturated resin towers, i.e. the (n+2)th tower, the (n+3)th tower, the (n+4)th tower and the (n+5)th tower, start a new saturated re-adsorption process and elution process, i.e. return to step S1, until the parameters of the resin phase and the liquid phase in the (n+2)th tower, the (n+3)th tower and the (n+4)th tower are consistent with the parameters of the in-situ hydrometallurgy process.

[0017] As a preferred solution: for step S1, X=3, i.e. when the uranium concentration of the effluent of the (n+4)th tower is higher than 3 g / L, the (n+4)th tower is disconnected.

[0018] As a preferred solution: for step S3, Y=0.8, i.e. when the uranium concentration of the effluent of the (n+1)th tower is lower than 0.8 g / L, the (n+1)th tower is cut off for transformation.

[0019] As a preferred solution: the elution line speed is 0.25 m / h.

[0020] As a preferred solution: the saturated resin tower used in the three-tower moving bed parallel adsorption process is DN3000×8500.

[0021] As a preferred solution: the saturated resin tower used in the one-tower saturated resin rinsing process is DN2000×5500.

[0022] As a preferred solution: the saturated resin tower used in the four-tower fixed bed series elution process is DN2000×5500.

[0023] As a preferred solution: the saturated resin tower used in the two-tower fixed bed transformation and post-elution qualified liquid hydrochloric acid acidification and alkali precipitation process is DN2000×5500.

[0024] As a preferred solution: two-tower fixed bed transformation and post-washing qualified liquid hydrochloric acid acidification and alkali precipitation process, the final point pH = 4.0.

[0025] The beneficial effects of the present application are:

[0026] (1) The fixed bed U-shaped tower leaching process of the present application adopts a three-tower moving bed parallel adsorption-one tower saturated resin rinsing-four tower fixed bed series leaching-two tower fixed bed transformation and post-washing qualified liquid hydrochloric acid acidification and alkali precipitation-slurry plate frame after the product "111" process, under the premise that the composition of the leaching agent remains basically unchanged, improves the leaching efficiency, reduces the consumption of leaching agent, and increases the uranium concentration in the leaching qualified liquid, so as to reduce the unit consumption of alkali in the qualified liquid precipitation process.

[0027] (2) The fixed bed U-shaped tower leaching process of the present application further improves the uranium capacity of saturated resin by using saturated resin re-adsorption technology, and the uranium concentration of the leaching qualified liquid can reach about 70g / L, which is doubled compared with the existing technology of 35g / L; due to the increase of the concentration of the leaching qualified liquid, the amount of acid for acidification and the amount of alkali for precipitation change to a certain extent, and through experiments, the reduction rate of unit acid consumption and unit alkali consumption is more than 20%.

[0028] (3) The fixed bed U-shaped tower leaching process of the present application introduces the U-shaped tower leaching technology in the acid leaching process of uranium into the alkali leaching or neutral leaching process of uranium, improves the leaching and saturated resin re-adsorption efficiency, and reduces the amount of leaching agent by 34% compared with the existing technology when leaching the same amount of uranium saturated resin. That is, by using density flow, the liquid is fed from the top during leaching, and the uranium desorbed from the resin will relatively quickly leave the resin and flow out of the tower with the flow rate of the leaching agent, instead of the opposite (if the liquid is fed from the bottom during leaching, part of the uranium leached from the resin will not be able to leave the resin or the tower in time due to gravity) ; and when saturated re-adsorption, the liquid is fed from the bottom, and most of the uranium in the high-concentration leaching qualified liquid will be adsorbed by the resin during the re-adsorption process from bottom to top, and a small part of the uranium not adsorbed will also slow down due to gravity compared with water molecules, so that the saturated resin in the same unit volume can re-adsorb more qualified liquid under the same conditions without the tail liquid running high, instead of the opposite (if the saturated resin is also fed from the top during re-adsorption, part of the unadsorbed uranium molecules will run ahead of the water molecules due to gravity, causing the tail liquid of re-adsorption to run high in advance, and the re-adsorption effect is poor). At the same time, the problems of large volume of the U-shaped tower in the existing technology, difficult maintenance, and long time to re-form the gradient after the gradient of the resin is disturbed are solved.

[0029] (4) The fixed bed U-shaped tower leaching process of the application changes the liquid inlet mode of the fixed bed leaching tower by using valves and corresponding pipelines, so that the liquid can be inlet from the top or the bottom. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The saturated re-adsorption flow chart of the application is shown in the figure;

[0031] Figure 2 The leaching flow chart of the application is shown in the figure;

[0032] Figure 3 The saturated re-adsorption tail liquid gradient is shown in the figure;

[0033] Figure 4 The 1 # The change trend of the qualified liquid uranium concentration of the production line. DETAILED DESCRIPTION

[0034] The fixed bed U-shaped tower leaching process of the application will be described in detail below in combination with the drawings and examples.

[0035] The fixed bed U-shaped tower leaching process of the application adopts three-tower moving bed parallel adsorption-one-tower saturated resin rinsing-four-tower fixed bed series leaching-two-tower fixed bed transformation and post-leaching qualified liquid hydrochloric acid acidification and alkali precipitation-slurry plate frame and "111" product design.

[0036] The three-tower moving bed parallel adsorption adopts the existing technology. The saturated resin tower used in the three-tower moving bed parallel adsorption process can be DN3000x8500.

[0037] The one-tower saturated resin rinsing adopts the existing technology. The existing technology has three moving bed adsorption towers and six leaching and transformation towers in each production line. Since the adsorption period is long enough, one leaching and transformation tower can be modified for saturated resin rinsing without increasing the number of leaching and transformation towers, and the remaining five leaching and transformation towers can still realize four-tower leaching and two-tower transformation. In the one-tower saturated resin rinsing process, the saturated resin tower used can be DN2000x5500.

[0038] The two-tower fixed bed transformation and post-leaching qualified liquid hydrochloric acid acidification and alkali precipitation adopt the existing technology. In the two-tower fixed bed transformation and post-leaching qualified liquid hydrochloric acid acidification and alkali precipitation process, the saturated resin tower used can be DN2000x5500, and the terminal acidity is preferably pH=4.0.

[0039] The slurry plate frame and "111" product adopt the existing technology.

[0040] The four-tower fixed bed series elution process includes a saturated re-adsorption process and an elution process. In the four-tower fixed bed series elution process, the saturated resin tower model used can be DN2000×5500.

[0041] Step S1

[0042] Saturation re-adsorption process Figure 1 As shown. For the Nth round of saturated re-adsorption, the four saturated resin towers are (n+1)#, (n+2)#, (n+3)#, and (n+4)#, where n = N-1. The eluent flows into the (n+1)# tower from the top, with its effluent flowing out from the bottom. Then, it flows into the (n+2)# tower from the top, with its effluent flowing out from the bottom. Then, it flows into the (n+3)# tower from the bottom, with its effluent flowing out from the top. Finally, it flows into the (n+4)# tower from the bottom, with its effluent flowing out from the top. The effluent from the (n+4)# tower is the re-adsorption tail liquid with low uranium and chloride concentrations.

[0043] When the uranium concentration of the effluent from the (n+4)# tower exceeds X g / L, the (n+4)# tower is disconnected and placed in an immersion re-adsorption state. The (n+1)#, (n+2)#, and (n+3)# towers then enter the elution process. For step S1, X is preferably 3, meaning that when the uranium concentration of the effluent from the (n+4)# tower exceeds 3 g / L, the (n+4)# tower is disconnected.

[0044] Step S2

[0045] The elution process is as follows Figure 2 As shown. Keep the liquid inlet method of the (n+1)# tower and the (n+2)# tower unchanged, and change the liquid inlet method of the (n+3)# tower from bottom liquid inlet to top liquid inlet. That is, the liquid outlet of the (n+2)# tower flows into the top of the (n+3)# tower, and the three towers are eluted in series. The liquid outlet of the (n+3)# tower flows into the qualified liquid storage tank.

[0046] Step S3

[0047] When the uranium concentration of the effluent of the (n+1)th column is lower than Y g / L, the (n+1)th column is cut off for transformation, at the same time, the effluent of the (n+3)th column no longer flows into the qualified liquid tank, but flows into the bottom of the (n+4)th column in the way of feed liquid, and the effluent of the (n+4)th column flows into the bottom of the newly connected saturated resin column, i.e. the (n+5)th column, in the way of feed liquid, at this time, the four saturated resin columns, i.e. the (n+2)th column, the (n+3)th column, the (n+4)th column and the (n+5)th column, start a new round of saturated re-adsorption process and elution process, i.e. return to step S1, until the indicators of the resin phase and the liquid phase in the (n+2)th column, the (n+3)th column and the (n+4)th column basically match the on-site hydrometallurgical process parameters. For step S3, Y is preferably 0.8, i.e. when the uranium concentration of the effluent of the (n+1)th column is lower than 0.8 g / L, the (n+1)th column is cut off for transformation.

[0048] The indoor bench test of the four-column fixed-bed series elution process is as follows.

[0049] (1) Test conditions

[0050] Saturated resin: from a certain plant 1 # production line, capacity 69.69 mg / mL 湿R

[0051] Eluent: from a certain plant 1 # eluent preparation tank of the production line, density p(U): 50.9 mg / L, p(Cl - ): 96.46 g / L, p(HCO3 - ): 20.57 g / L, pH: 9.18.

[0052] (2) Test equipment and parameters

[0053] ① Resin column volume

[0054] According to the height-diameter ratio of the elution column on the production site, the specification of the test elution column is DN110*310, the resin layer height is 200 mm, and the column volume is For accurate metering, the saturated resin needs to be rinsed clean with water before column loading.

[0055] ② Liquid phase flow rate

[0056] The solution contact time with the resin is about 400 min, and the elution flow rate Q 瞬时 is calculated as 1600*0.4 / 400=1.6 mL / min.

[0057] (3) Test steps

[0058] ① Preparation of equal-gradient resin phase

[0059] The three towers above are connected in series, the amount of eluent is controlled according to the requirement, and elution is carried out at the corresponding elution line speed. When the uranium concentration of the first tower effluent reaches 0.64 g / L, the first tower is cut off, and the corresponding second tower is used as the first elution tower, the third tower is used as the second tower, and the newly added saturated resin tower is used as the third tower to start a new round of elution. After 22 tower passes of elution, the resin phase and liquid phase of the three towers basically match the on-site hydrometallurgical process parameters.

[0060] ②Saturated re-adsorption test

[0061] The 20 # , 21 # , 22 # towers used in the previous elution process are continued to be used, a new elution tower 23 # is connected, the eluent is fed from the bottom and discharged from the top, and the flow rate is 1.6 mL / min. After the eluent passes through the 20 # , 21 # elution towers in the upward flow mode, it is changed to the downward flow mode to enter the 22 # , 23 # towers, and the saturated re-adsorption process is carried out, as shown in Figure 1 . When the uranium concentration of the saturated re-adsorption tail liquid reaches 5 g / L, the last tower is cut off, the elution is carried out according to the operation of the previous process "preparation of equal-gradient resin phase", and after the elution is completed, a new saturated resin tower is connected to start the saturated re-adsorption. This is repeated. # The uranium capacity of the resin increases from 69.69 mg / mL wet resin to 89.39 mg / mL wet resin, indicating that the uranyl carbonate type resin has a certain re-adsorption capacity.

[0062] (4) Test results

[0063] After 5 tower passes of saturated re-adsorption and elution, the indicators of the elution qualified liquid are shown in Table 1.

[0064] Table 1 Indicators of elution qualified liquid

[0065]

[0066] As can be seen from the data in the table, the uranium concentration of the elution qualified liquid increases continuously from 56.29 g / L to about 68 g / L and stabilizes, so the saturated re-adsorption process has considerable application value in the fixed bed hydrometallurgical process of neutral leaching mines.

[0067] Example

[0068] A hydrometallurgical plant has a total of 4 production lines, of which 1 # production line and 2 # production line share a primary liquid, 3 # production line and 4 #The production line shared the second-stage raffinate. After research, it was decided to select the first stage of the saturated resin with lower capacity # The production line carried out expansion test. It took 36 days to complete the test on the first stage of the saturated resin with lower capacity # The production line carried out expansion test. It took 36 days to complete the test on the first stage of the saturated resin with lower capacity

[0069] 1 Process transformation and test preparation

[0070] 1.1 Process transformation

[0071] Without increasing the tower equipment, the valve and the corresponding pipeline were used to change the liquid inlet mode of the fixed bed elution tower, which could be both up and down, to realize the four-tower elution process.

[0072] The on-site transformation mainly included: tower down liquid pipeline installation, tower top sight glass installation, saturated re-adsorption tail liquid sight glass, re-adsorption tail liquid discharge pipeline installation, automatic exhaust valve installation, saturated re-adsorption tail liquid tank preparation.

[0073] This transformation consumed 4 DN40 PVC ball valves, 1 DN50 PVC ball valve, 10 meters of DN50 PVC pipe, 20 meters of DN40 PVC pipe for each tower, and other expenses of 200 yuan, totaling 1195 yuan per tower, and 5975 yuan in total.

[0074] 1.2 Test preparation

[0075] The original elution liquid tank 504 was selected as the saturated re-adsorption tail liquid tank, and the 101 adsorption tower discharged saturated resin twice a day for two consecutive days and stored in the elution tower for standby.

[0076] 2 Optimization of process parameters and test data

[0077] 2.1 Optimization of process parameters

[0078] At the beginning of the test, the resin bed height, elution end point first tower liquid uranium concentration index and elution agent flow were all based on the water metallurgy process parameters of a certain factory. After 14 tower runs, the parameters were optimized to fully utilize the advantages of the process.

[0079] Firstly, the adsorption cycle was extended. Due to the increase of saturated re-adsorption process, the resin treatment time would increase, which would lead to the accumulation of uranium in the adsorption process. Considering the adsorption flow and the time of treating resin, the saturated resin discharge amount was adjusted from the original 11m3 to 16m3, which fully utilized the space of the elution tower, and because of the increase of saturated resin discharge amount per tower per time, the adsorption cycle was extended, which provided time guarantee for the saturated resin rinsing, saturated resin re-adsorption and elution and transformation, and the system ran smoothly.

[0080] Secondly, the uranium concentration of the elution end point is improved. With the increase of the resin bed volume, if the uranium concentration of the first column effluent at the elution end point is still 1.0 g / L, the elution efficiency will increase, the volume of the eluent will also increase, and the qualified liquid uranium concentration will decrease. After comprehensive consideration, the uranium concentration of the first column effluent at the elution end point is adjusted from 1.0 g / L to 1.5 g / L.

[0081] Finally, the elution line speed is reduced and the contact time of the eluent and the resin is prolonged. During the initial operation, the improvement of the qualified liquid uranium concentration is not obvious. After referring to the indoor test parameters, it is found that the contact time of the eluent and the resin is not enough. After comparison of 1.7 m3 / h, 1.2 m3 / h, 1.0 m3 / h and 0.8 m3 / h, the effect of 0.8 m3 / h is the best. Therefore, the eluent flow is set to 0.8 m3 / h and the elution line speed is 0.25 m / h.

[0082] The direction of the saturated re-adsorption tail liquid needs to be studied. The uranium concentration of the saturated re-adsorption tail liquid is about 1.0 g / L, and the chloride concentration is about 3.0 g / L, which cannot meet the direct discharge condition of the evaporation pond. If the conditions permit, the optimal choice is to increase the recovery adsorption tower to specially process the saturated re-adsorption tail liquid. Because there is no recovery adsorption process in the fixed bed uranium hydrometallurgy process of a certain plant, it means that other methods must be sought to treat the saturated re-adsorption tail liquid. Initially, it is assumed that the tail liquid is circulated into the saturated resin tower and treated to the discharge level. Through several tests, the uranium concentration of the saturated re-adsorption tail liquid after circulation still maintains a high level (0.6 g / L), and the chloride concentration changes little. Through the study of the saturated re-adsorption tail liquid curve, it is found that most of them are below 0.3 g / L. See the following table for details. Figure 3 .

[0083] In view of this situation, it is decided to adopt segmented processing. The part below 0.3 g / L is directly discharged (about 8 m 3 , and the average concentration is about 0.16 g / L), and the part from 0.3 g / L to 3 g / L is stored in the saturated re-adsorption tail liquid tank (about 5 m 3 ). The pump is used to pump it into the last tower before the next saturated re-adsorption. After 5 tower times of operation, it is proved that this method is feasible.

[0084] 2.2 Test data

[0085] After 9 tower times of saturated re-adsorption and elution after optimization of the parameters, the qualified liquid uranium concentration is improved from the initial 45.23 g / L to 74.23 g / L, and the average value is 57.45 g / L.

[0086] The change trend of the elution qualified liquid uranium concentration is shown in the following figure. Figure 4 .

[0087] The same period 2 #The concentration of the qualified liquid uranium in the production line was maintained at about 40 g / L, with an average of 42.83 g / L, as shown in Table 2.

[0088] Table 2 Resin elution data without saturation and re-adsorption

[0089]

[0090]

[0091] From the data in Table 2, it can be seen that: ① The concentration of the qualified liquid uranium in the production line was maintained at about 40 g / L, with an average of 42.83 g / L, as shown in Table 2. # The concentration of the qualified liquid uranium in the production line was maintained at about 40 g / L, with an average of 42.83 g / L, as shown in Table 2. # The concentration of the qualified liquid uranium in the production line was maintained at about 40 g / L, with an average of 42.83 g / L, as shown in Table 2. # The concentration of the qualified liquid uranium in the production line was maintained at about 40 g / L, with an average of 42.83 g / L, as shown in Table 2. # The concentration of the qualified liquid uranium in the production line was maintained at about 40 g / L, with an average of 42.83 g / L, as shown in Table 2. # The concentration of the qualified liquid uranium in the production line was maintained at about 40 g / L, with an average of 42.83 g / L, as shown in Table 2.

[0092] 2.3 Test of acid consumption in acidification of the qualified liquid

[0093] Randomly selected 1 # , 2 # L of the qualified liquid in the field production, 400 mL of each was placed in a beaker and placed on a magnetic stirrer, the magnetic stirrer was started, and the volume of the analytically pure hydrochloric acid consumed was measured and recorded when the pH was 4.0. Then, 20% caustic soda solution was used for titration, and the volume of the caustic soda consumed was measured and recorded when the pH was 12.5, as shown in Table 3.

[0094] Table 3 Data recording table for acidification and precipitation of the qualified liquid

[0095] project 1 # production line qualified liquid 2 # production line qualified liquid Remark Qualified liquid uranium concentration (g / L) 49.36 36.4 Acidification endpoint pH 4.0 4.0 Hydrochloric acid consumption volume (mL) 41.7 38.2 Precipitation endpoint pH 12.5 12.5 Caustic soda consumption volume (mL) 42 40

[0096] From Table 3, it can be calculated that 1 # The acid consumption per unit mass of the qualified liquid in the production line was 0.84 mL / g, 2 # The acid consumption per unit mass of the qualified liquid in the production line was 1.09 mL / g, 1 # The acid consumption of the production line was 2 # The acid consumption of the production line was 77.06%, saving 22.96%; similarly, 1 # The acid consumption per unit mass of the qualified liquid in the production line was 0.84 mL / g, 2 # The acid consumption per unit mass of the qualified liquid in the production line was 1.098 mL / g, 1 # The acid consumption of the production line was 2 # The acid consumption of the production line was 77.4%, saving 22.6%, i.e.: the reduction rate of unit acid consumption and unit base consumption was more than 20%.

[0097] 3. Test results

[0098] The results of the indoor test and the production line expansion test show that the four-tower elution process, i.e. the fixed-bed U-shaped tower elution technology, is feasible and does not require large equipment and facility modification. No additional qualified liquid lean liquid tank is needed. The four saturated resin towers are only connected in series through different liquid inlet ways.

[0099] Due to the resorption of the saturated resin and the increase of its uranium capacity, the elution qualified liquid uranium concentration can reach about 70 g / L, which is nearly doubled compared with the previous improvement. Due to the U-shaped tower elution technology, the elution efficiency and the saturation resorption efficiency are improved, and the amount of eluant used for the saturation of the same amount of uranium resin is reduced by 34%. Due to the increase of the qualified liquid concentration, the amount of acid used for acidification and the amount of alkali used for precipitation are relatively reduced. Through the indoor test, the reduction of the unit acid consumption and the unit alkali consumption is more than 20%.

[0100] The production parameters of the neutral leaching mine uranium saturated resin fixed-bed four-tower elution process are provided below for reference.

[0101] Resin tower volume: 16 m3; tower internal empty height: 50-60 cm; elution flow rate: 0.8 m3 / h; elution line speed: 0.25 m / h; eluant component concentration: Cl - (90-95 g / L); HCO3 - (15-20 g / L); saturated resorption end point tail liquid uranium concentration: 3 g / L; saturated resorption tail liquid separation standard: 0.3 g / L or less discharged, 0.3 g / L to 3 g / L into the saturated resorption tail liquid storage tank;

[0102] Elution tower pressure: 0.1-0.15 MPa; qualified liquid uranium concentration: about 65 g / L; elution end point: 1.5 g / L; post-elution lean resin uranium capacity: less than 1.0 mg / mL wet R; solution and resin single tower contact time: 7.4 h.

Claims

1. A fixed bed U-shaped tower elution process, characterized in that: The "111" product design uses three moving beds in parallel for adsorption, one saturated resin rinsing tower, four fixed beds in series for leaching, two fixed beds for transformation and leaching, hydrochloric acid acidification of the qualified liquid after leaching, followed by alkali precipitation, and the slurry is punched on the plate frame to produce the "111" product. Among them, the four-tower fixed bed series elution process includes the following saturated re-adsorption process and elution process; Step S1 For the Nth round of saturated re-adsorption process, the four saturated resin towers are (n+1)#tower, (n+2)#tower, (n+3)#tower, and (n+4)#tower, where n=N-1; the eluent flows into the (n+1)#tower from the top in the above-mentioned manner, and its effluent flows out from the bottom of the tower; thereafter, the eluent flows into the (n+2)#tower from the top in the above-mentioned manner, and its effluent flows out from the bottom of the tower; thereafter, the eluent flows into the (n+3)#tower from the bottom in the below-mentioned manner, and its effluent flows out from the top of the tower; thereafter, the eluent flows into the (n+4)#tower from the bottom in the below-mentioned manner, and its effluent flows out from the top of the tower; the effluent of the (n+4)#tower is the re-adsorption tail liquid with low uranium concentration and low chloride ion concentration; When the uranium concentration of the effluent from the (n+4)# tower is higher than Xg / L, the (n+4)# tower is disconnected and placed in an immersion re-adsorption state, and the (n+1)# tower, (n+2)# tower, and (n+3)# tower enter the leaching process; Step S2 During the elution process, the liquid inlet method of the (n+1)# tower and the (n+2)# tower remains unchanged, and the liquid inlet method of the (n+3)# tower is changed from bottom inlet to top inlet, that is, the effluent of the (n+2)# tower flows into the top of the (n+3)# tower, and the three towers are eluted in series. The effluent of the (n+3)# tower flows into the qualified liquid storage tank; Step S3 When the uranium concentration of the effluent of the (n+1)# tower is lower than Yg / L, the (n+1)# tower is cut off for transformation. At the same time, the effluent of the (n+3)# tower no longer flows into the qualified liquid storage tank, but flows into the bottom of the (n+4)# tower in a downward liquid inflow manner. The effluent of the (n+4)# tower flows into the bottom of the newly connected saturated resin tower - (n+5)# tower in a downward liquid inflow manner. At this time, the four saturated resin towers (n+2)# tower, (n+3)# tower, (n+4)# tower, and (n+5)# tower begin a new round of saturated re-adsorption process and elution process, that is, return to step S1 until the various indicators of the resin phase and liquid phase in the three saturated resin towers (n+2)# tower, (n+3)# tower, and (n+4)# tower meet the on-site hydrometallurgical process parameters; The eluent pH: 9.18; In the process of hydrochloric acid acidification and alkali precipitation after the qualified liquid after the two-tower fixed bed transformation and leaching is added, the end point acidity pH is 4.

0.

2. The fixed bed U-shaped tower elution process according to claim 1, characterized in that: For step S1, X=3, that is, when the uranium concentration of the effluent from the (n+4)# tower is higher than 3 g / L, the (n+4)# tower is disconnected.

3. The fixed bed U-shaped tower elution process according to claim 1, characterized in that: For step S3, Y=0.8, that is, when the uranium concentration of the effluent from the (n+1)# tower is lower than 0.8 g / L, the (n+1)# tower is cut off for transformation.

4. The fixed bed U-shaped tower elution process according to claim 1, characterized in that: The elution line speed is 0.25m / h.

5. The fixed bed U-shaped tower elution process according to claim 1, characterized in that: The saturated resin tower model used in the three-tower moving bed parallel adsorption process is DN3000×8500.

6. The fixed bed U-shaped tower elution process according to claim 1, characterized in that: In the one-tower saturated resin rinsing process, the saturated resin tower model used is DN2000×5500.

7. The fixed bed U-shaped tower elution process according to claim 1, characterized in that: In the four-tower fixed bed series elution process, the saturated resin tower model used is DN2000×5500.

8. The fixed bed U-shaped tower elution process according to claim 1, characterized in that: In the process of two-tower fixed bed transformation and alkali precipitation after hydrochloric acid acidification of qualified liquid after leaching, the saturated resin tower model used is DN2000×5500.

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