Method for comprehensive recovery of uranium, thorium, titanium, zirconium and rare earths from green bed silicate cerite

Abstract

This invention relates to the field of ore mining and metallurgy, and particularly to a method for the comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layer cerium-titanium ore. The method includes: grinding the green-layer cerium-titanium ore to obtain a rough ore; performing two-stage magnetic separation on the rough ore (-1 to +0.074 mm) using a magnetic field to obtain a mixed concentrate; rinsing the mixed concentrate with acid to obtain a first qualified solution; subjecting the unleached portion to a first four-stage countercurrent washing, alkali transformation, acidification, and a second countercurrent washing to obtain a second qualified solution; after desiliconization and demulsification treatment of the first qualified solution, extraction, crystallization back-extraction to obtain uranium products; using phosphoric acid precipitation to obtain thorium, titanium, and zirconium precipitates from the raffinate; adding ammonia and polyacrylamide solution to the second qualified solution, reacting, and filtering to obtain crude products of thorium and other rare earth hydroxides. This invention achieves comprehensive recovery of thorium, rare earth elements, and other elements simultaneously with uranium leaching.

Description

Technical Field

[0001] This invention relates to the field of ore mining and metallurgy, and in particular to a comprehensive method for the recovery of uranium, thorium, titanium, zirconium and rare earth elements from green layer cerium-titanium ore. Background Technology

[0002] The Saima alkaline uranium deposit in Fengcheng, Liaoning Province, is a large-scale comprehensive deposit containing uranium, thorium, and rare earth elements. It is unique in my country and rare worldwide. Since its discovery in the 1970s, the deposit has attracted widespread attention from the uranium geology and mining communities. Some leaching tests were conducted at that time, but due to technical limitations, the uranium leaching rate was low, and the comprehensive recovery of other minerals was difficult.

[0003] The Saima uranium deposit is located in alkaline rocks. The main type of uranium ore is the green-bedded cerium-titanium silicate mineralization found in grass-green nephrite syenite. This constitutes the main body of the large-scale comprehensive deposit of uranium, thorium, rare earth elements, and niobium in Saima. The industrial minerals are green-bedded cerium-titanium silicate and its altered minerals to varying degrees. The uranium content varies between 0.05% and 0.1%, the thorium content between 0.15% and 0.4%, and the contents of cerium group rare earth elements and niobium all meet industrial requirements.

[0004] Green-layer cerium-titanium ore is a relatively rare type of uranium mineral in the world. Because most of the minerals are aluminosilicates or iron-silicates and contain rare earth elements, thorium, niobium, tantalum, etc., uranium minerals are difficult to leach. When using conventional acid leaching methods, not only is acid consumption high and leaching rate low, but it is also difficult to comprehensively recover and utilize thorium and other elements in the ore. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for the comprehensive recovery of uranium, thorium, titanium, zirconium and rare earth elements in green layer cerium titanate, which comprehensively recovers thorium, rare earth and other elements at the same time as uranium leaching.

[0006] This invention provides a method for the comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layer cerium-titanium ore, comprising the following steps:

[0007] Step S1: Grind the green layer cerium-titanium silicate ore to obtain a coarse ore with a diameter of -1 to 0 mm; wherein, the coarse ore with a diameter of -0.074 to 0 mm is used as ore slime and fed into the mixed concentrate.

[0008] Coarse ore with a diameter of -1 to +0.074 mm enters the next step for two-stage magnetic separation;

[0009] Step S2: Use a magnetic field to perform two-stage magnetic separation on the coarse ore of -1 to +0.074 mm to obtain mixed concentrate;

[0010] Step S3: The mixed concentrate is acid-treated and leached to obtain the first qualified solution; the unleached portion is sequentially subjected to the first four-stage countercurrent washing, alkali transformation, acidification, and the second countercurrent washing to obtain the second qualified solution.

[0011] Step S4: After the first qualified solution undergoes desiliconization and demulsification treatment, it is extracted, crystallized, and back-extracted to obtain uranium products. The raffinate aqueous phase is then precipitated with phosphoric acid to obtain thorium, titanium, and zirconium precipitates.

[0012] The second qualified solution was added to ammonia and polyacrylamide solution, reacted, and then filtered to obtain crude products of thorium and other rare earth hydroxides.

[0013] Preferably, step S2 specifically includes:

[0014] The first-stage magnetic separation of coarse ore of -1 to +0.074 mm is carried out using a magnetic field with a magnetic field strength of 10,000 to 11,000 Oersted. The ore that passes through is used as concentrate and enters the mixed concentrate.

[0015] A second-stage magnetic separation is performed on the ore that fails to pass through a magnetic field with an intensity of 12,000 to 13,000 Oersted. The portion that passes through enters the mixed concentrate, while the ore that fails through becomes tailings.

[0016] Preferably, in step S2: a magnetic field with a magnetic field strength of 10500 to 10700 Oersted is used to perform the first-stage magnetic separation on the coarse ore of -1 to +0.074 mm.

[0017] Preferably, step S3 specifically includes:

[0018] Step S3-1: Based on the quality of the mixed concentrate, add 2% calcium fluoride, 2.0% MnO2, and 22.0% H2SO4 to the mixed concentrate and heat at 120°C for 2 hours.

[0019] Step S3-2: Add 3.0% sulfuric acid and heat at 80°C for 2 hours; leach to obtain the first qualified solution;

[0020] Step S3-3: The unleached portion is washed with a sulfuric acid solution of pH=1 and water, with a volume ratio of sulfuric acid solution to water of 1:1.2. The resulting washing solution is returned to step S3-2 for further preparation of the first qualified solution. The remaining portion is alkali-converted with an aqueous solution of NaOH of pH=9, with a volume ratio of NaOH to water of 1:1.2. Then, 0.5% H2SO4 is added for acidification to obtain the second qualified solution.

[0021] The remaining portion is mixed with a sulfuric acid solution of pH 1.5 and water, with a volume ratio of sulfuric acid solution to water of 1:1.2. The washing liquid is returned to prepare a second qualified solution; the remaining portion is discarded as tailings.

[0022] Preferably, in step S4, the desiliconization and demulsification process specifically includes:

[0023] Add polyether solution and polyacrylamide solution to the first qualified solution, stir, filter, and use the filtrate for extraction;

[0024] The polyether solution has a mass percentage concentration of 1% and a dosage of 100 g / m³. 3 The polyacrylamide solution has a mass percentage concentration of 0.5% and a dosage of 200 g / m³. 3 .

[0025] Preferably, in step S4, the extraction specifically includes:

[0026] The filtrate was added to an organic phase for four-stage countercurrent extraction. The organic phase consisted of a sulfonated kerosene solution containing 0.05 MN-235 and 2 (v)% mixed alcohols.

[0027] The equilibrium ratio O / A = 1 / 5, while the contact ratio O / A > 1;

[0028] Contact time: 2 minutes.

[0029] Preferably, in step S4, the crystallization back-extraction specifically includes:

[0030] The saturated organic phase obtained by the four-stage countercurrent extraction is washed once with sulfuric acid water at pH 1.5, with an O / A ratio of 10 / 1. Then, uranium is back-extracted from N-235 using ammonium carbonate or ammonium sulfate for crystallization back-extraction to obtain the uranium product.

[0031] Preferably, in step S4, the pH value of the raffinate is adjusted with ammonia, H3PO4 is added to pH = 3.0-3.5, the mixture is stirred for 0.5 hours, polyacrylamide solution is added 5 minutes before stopping the stirring, and the mixture is filtered to obtain precipitates of thorium, titanium and zirconium.

[0032] The amount of polyacrylamide solution used is 100 g / m³. 3 溶液 .

[0033] Preferably, before adjusting the pH of the raffinate aqueous phase with ammonia, iron is added to remove Fe from the solution. 3+ Reduced to Fe 2+ .

[0034] Preferably, in step S4, the second qualified solution is neutralized with ammonia water to pH = 8, and stirred at 15°C for 10 minutes; then 20 g / m³ of polyacrylamide solution is added. 3 溶液 Filtration after flocculation;

[0035] The mother liquor and precipitate were dried at 105°C to obtain crude products of thorium and other rare earth hydroxides.

[0036] Compared with existing technologies, the comprehensive recovery method for uranium, thorium, titanium, zirconium, and rare earth elements from green-layer cerium-titanium ore of the present invention first performs dry magnetic separation to obtain a mixed concentrate. The mixed concentrate is then processed to prepare a first qualified solution and a second qualified solution. Uranium products, thorium, titanium, and zirconium precipitates are then obtained from the first qualified solution; crude sodium hydroxide products of thorium and other rare earth elements are obtained from the second qualified solution. This invention explores the conditions and steps for the recovery and extraction of multiple elements, achieving comprehensive recovery of thorium, titanium, zirconium, and other rare earth elements simultaneously with uranium leaching, resulting in high recovery efficiency. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating the dry magnetic separation process.

[0038] Figure 2 A graph showing the comparison of experiments with different parameters;

[0039] Figure 3 This graph shows the relationship between various factors and the leaching rate K value. Detailed Implementation

[0040] To further understand the present invention, embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the present invention.

[0041] The Siberian polyacrylamide solution mentioned in this invention refers to the solution of polyacrylamide.

[0042] An embodiment of the present invention discloses a method for the comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layer cerium-titanium ore, comprising the following steps:

[0043] Step S1: Grind the green layer cerium-titanium silicate ore to obtain a coarse ore with a diameter of -1 to 0 mm; wherein, the coarse ore with a diameter of -0.074 to 0 mm is used as ore slime and fed into the mixed concentrate.

[0044] Coarse ore with a diameter of -1 to +0.074 mm enters the next step for two-stage magnetic separation;

[0045] Step S2: Use a magnetic field to perform two-stage magnetic separation on the coarse ore of -1 to +0.074 mm to obtain mixed concentrate;

[0046] Step S3: The mixed concentrate is acid-treated and leached to obtain the first qualified solution; the unleached portion is sequentially subjected to the first four-stage countercurrent washing, alkali transformation, acidification, and the second countercurrent washing to obtain the second qualified solution.

[0047] Step S4: After the first qualified solution undergoes desiliconization and demulsification treatment, it is extracted, crystallized, and back-extracted to obtain uranium products. The raffinate aqueous phase is then precipitated with phosphoric acid to obtain thorium, titanium, and zirconium precipitates.

[0048] The second qualified solution was added to ammonia and polyacrylamide solution, reacted, and then filtered to obtain crude products of thorium and other rare earth hydroxides.

[0049] According to this invention, the ore is first ground and classified. Specifically:

[0050] Step S1: Grind the green layer cerium-titanium silicate ore. A 200×240m / m rod mill can be used for wet open-circuit grinding to obtain a coarse ore of -1 to 0mm. Among them, the coarse ore of -0.074 to 0mm is used as ore slime and fed into the mixed concentrate.

[0051] Coarse ore with a diameter of -1 to +0.074 mm enters the next step for two-stage magnetic separation;

[0052] Step S2: Use a magnetic field to perform two-stage magnetic separation on the coarse ore of -1 to +0.074 mm to obtain mixed concentrate;

[0053] Preferably, step S2 specifically includes:

[0054] The first-stage magnetic separation of coarse ore of -1 to +0.074 mm is carried out using a magnetic field with a magnetic field strength of 10,000 to 11,000 Oersted, preferably 10,500 to 10,700 Oersted, and more preferably 10,600 Oersted. The ore that passes through is used as concentrate and enters the mixed concentrate.

[0055] A second-stage magnetic separation is performed on the ore that fails to pass through a magnetic field with an intensity of 12,000 to 13,000 Oersted, preferably 12,000 Oersted. The portion that passes through enters the mixed concentrate, while the ore that fails through becomes tailings.

[0056] After obtaining the mixed concentrate, a qualified solution is prepared using the mixed concentrate, specifically:

[0057] Step S3: The mixed concentrate is acid-treated and leached to obtain the first qualified solution; the unleached portion is sequentially subjected to the first four-stage countercurrent washing, alkali transformation, acidification, and the second countercurrent washing to obtain the second qualified solution.

[0058] Preferably, step S3 specifically includes:

[0059] Step S3-1: Based on the quality of the mixed concentrate, add 2% calcium fluoride, 2.0% MnO2, and 22.0% H2SO4 to the mixed concentrate and heat at 120°C for 2 hours.

[0060] 2% calcium fluoride refers to 2% of the mass of the mixed concentrate as calcium fluoride added; 2.0% MnO2 refers to 2% of the mass of the mixed concentrate as MnO2 added; and 22.0% H2SO4 refers to 22% of the mass of the mixed concentrate as H2SO4 added.

[0061] Step S3-2: Add 3.0% sulfuric acid and heat at 80°C for 2 hours; leach to obtain the first qualified solution;

[0062] The meaning of 3.0% sulfuric acid is the same as above, referring to the amount of sulfuric acid added.

[0063] Step S3-3: The unleached portion is washed with a sulfuric acid solution of pH=1 and water, with a volume ratio of sulfuric acid solution to water of 1:1.2. The resulting washing solution is returned to step S3-2 for further preparation of the first qualified solution. The remaining portion is alkali-converted with an aqueous solution of NaOH of pH=9, with a volume ratio of NaOH to water of 1:1.2. Then, 0.5% H2SO4 is added for acidification to obtain the second qualified solution.

[0064] The remaining portion is mixed with a sulfuric acid solution of pH 1.5 and water, with a volume ratio of sulfuric acid solution to water of 1:1.2. The washing liquid is returned to prepare a second qualified solution; the remaining portion is discarded as tailings.

[0065] After obtaining the first and second qualified solutions, the elements within them are separated. Specifically, this includes:

[0066] Step S4: After the first qualified solution undergoes desiliconization and demulsification treatment, it is extracted, crystallized, and back-extracted to obtain uranium products. The raffinate aqueous phase is then precipitated with phosphoric acid to obtain thorium, titanium, and zirconium precipitates.

[0067] The second qualified solution was added to ammonia and polyacrylamide solution, reacted, and then filtered to obtain crude products of thorium and other rare earth hydroxides.

[0068] Uranium extraction from N-235 is carried out in the first qualified solution. Although the ore was matured with calcium fluoride and acid before leaching, the leachate still contained a considerable amount of SiO2. A pre-treatment with polyether-Siberian alloys before extraction ensures smooth extraction-back-extraction. Desiliconization and demulsification are performed first.

[0069] The desilicone demulsification process specifically includes:

[0070] Add polyether solution and polyacrylamide solution to the first qualified solution, stir, filter, and use the filtrate for extraction;

[0071] The polyether solution has a mass percentage concentration of 1% and a dosage of 100 g / m³. 3 The polyacrylamide solution has a mass percentage concentration of 0.5% and a dosage of 200 g / m³. 3 .

[0072] The extraction specifically includes:

[0073] The filtrate was added to an organic phase for four-stage countercurrent extraction. The organic phase consisted of a sulfonated kerosene solution containing 0.05 MN-235 and 2 (v)% mixed alcohols.

[0074] The equilibrium ratio O / A = 1 / 5, while the contact ratio O / A > 1;

[0075] Contact time: 2 minutes.

[0076] The mixed alcohols are C7-C9 alcohols.

[0077] The crystallization back-extraction specifically includes:

[0078] The saturated organic phase obtained by the four-stage countercurrent extraction is washed once with sulfuric acid water at pH 1.5, with an O / A ratio of 10 / 1. Then, uranium is back-extracted from N-235 using ammonium carbonate or ammonium sulfate for crystallization back-extraction to obtain the uranium product.

[0079] In step S4, iron is first added to the raffinate phase to remove Fe from the solution. 3+ Reduced to Fe 2+ The pH value was adjusted with ammonia water, and H3PO4 was added to make the pH = 3.0-3.5. The mixture was stirred for 0.5 hours. Five minutes before stopping the stirring, polyacrylamide solution was added, and the mixture was filtered to obtain precipitates of thorium, titanium and zirconium.

[0080] The amount of polyacrylamide solution used is 100 g / m³. 3 溶液 The mass concentration of the polyacrylamide solution is 0.5%.

[0081] In step S4, the second qualified solution is neutralized with ammonia water to pH = 8 and stirred at 15°C for 10 minutes; then 20 g / m³ of polyacrylamide solution is added. 3 溶液 Filtration after flocculation;

[0082] The mother liquor and precipitate were dried at 105°C to obtain crude products of thorium and other rare earth hydroxides.

[0083] To further understand the present invention, the following detailed description of the comprehensive recovery method of uranium, thorium, titanium, zirconium and rare earth elements in green layer cerium-titanium ore provided by the present invention is provided in conjunction with the embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0084] Example 1

[0085] Experiments were conducted using alkaline uranium ore from Saima.

[0086] (I) Grinding

[0087] Step 1: Wet open-circuit grinding was performed using a 200×240m / m rod mill with parameters shown in Table 1. The raw ore had a uranium grade of 0.055% and a thorium grade of 0.171%.

[0088] Table 1 Rod loading status of the rod mill

[0089] 15.0 35 17 4.9 17.5 30 9 4.2 20.0 35 9 4.9 total 100 35 14.0

[0090] (II) Screening

[0091] The -1 to 0 mm ore is screened into -0.074 to 0 mm and -1 to 0.074 mm. The -1 to +0.074 mm ore is subjected to magnetic separation, and the -0.074 to 0 mm ore is used as slime and fed into the mixed concentrate.

[0092] (III) Dry magnetic separation.

[0093] The 138-δCЭ type dry single-roll magnetic separator performs magnetic separation. Magnetic separation consists of two steps:

[0094] 1. First-stage magnetic separation

[0095] Magnetic separation was performed on ore with a magnetic field strength of 10600 Oersted and a diameter of -1 to +0.074 mm. The portion of the ore that passed through was fed into the mixed concentrate. The portion that did not pass through underwent a second stage of magnetic separation.

[0096] 2. Second-stage magnetic separation

[0097] The ore that failed the first-stage magnetic separation was subjected to magnetic separation using a magnetic field strength of 12000 Oersted. The portion of the ore that passed the first-stage magnetic separation was used as concentrate and entered into the mixed concentrate. The portion that failed the first-stage magnetic separation became tailings.

[0098] 3. Magnetic separation effect

[0099] 1) Mixed concentrate

[0100] Yield: 71.17%, uranium grade: 0.073%, thorium grade: 0.226%. Uranium recovery: 94.85%, thorium recovery: 94.00%.

[0101] 2) Tailings

[0102] Yield 28.83%, uranium grade 0.0098%, thorium grade 0.036%, uranium loss rate 5.15%, thorium loss rate 6.00%.

[0103] (iv) Uranium extraction from N-235

[0104] 1. Preparation of leachate

[0105] (1) Preparation of the first qualified solution

[0106] Step 1: Acid maturation. Based on the quality of the mixed concentrate, add 2.0% CaF2, 2.0% MnO2, and 22.0% H2SO4 to the mixed concentrate and heat at 120℃ for 2 hours.

[0107] Step 2: Leaching. Add 3.0% sulfuric acid and heat at 80°C for 2 hours. Leaching yields the first qualified solution; the unleached portion is used to prepare the second qualified solution.

[0108] (2) Preparation of the second qualified solution

[0109] Step 3, four-stage countercurrent washing. Add sulfuric acid solution (pH=1) and water in a 1:1.2 ratio for washing. The resulting washing solution is returned to Step 2 for further preparation of the first qualified solution. The remaining sections undergo a single-stage alkali transition.

[0110] Step 4, alkaline transition. Add NaOH solution with pH=9 and water in a ratio of 1:1.2.

[0111] Step 5, initial acidification. Add 0.5% H2SO4. Obtain a second qualified solution. The remaining portion proceeds to step 6.

[0112] Step 6: Four-stage countercurrent washing. Add H₂SO₄ (pH 1.5) and water in a ratio of 1:1.2. Pour the washing solution into Step 5 to prepare the second qualified solution. The remaining portion is discarded as tailings.

[0113] (3) Component analysis of qualified solution

[0114] Table 2 Chemical analysis results of the first qualified solution

[0115] content% 0.403 0.434 0.642 2.173 6.492 0 1.320 3.260 0.707 Analysis Project Mg Mn <![CDATA[∑RE2O3]]> <![CDATA[F - ]]> <![CDATA[SO4 2- ]]> <![CDATA[PO4 3- ]]> pH Potential (mV) content% 1.241 3.440 0.440 0.940 89.391 0.180 1.05 520

[0116] Table 3 Chemical analysis results of the second qualified solution

[0117] content% 0.015 0.459 0.675 0.304 0.378 0.016 0.008 3.00 0.140 Analysis Project <![CDATA[SO4 2- ]]> <![CDATA[PO4 3- ]]> pH Potential (mV) content% 10.760 1.50 500

[0118] The analysis results in Tables 2 and 3 show that uranium, titanium, and zirconium are mainly concentrated in the first qualified solution, rare earth elements are mainly concentrated in the second qualified solution, and thorium accounts for roughly half in both qualified solutions.

[0119] 2. N-235 uranium immersion

[0120] Uranium extraction from N-235 is carried out in the first qualified solution. Although the ore was matured with calcium fluoride and acid before leaching, the leachate still contained a considerable amount of SiO2. A pre-treatment with polyether-Siberian alloys before extraction ensures smooth extraction-back-extraction. Desiliconization and demulsification are performed first.

[0121] 1) Orthogonal test for desiliconization and demulsification

[0122] Three levels were set for the three factors: polyether dosage, Siberon dosage, and stirring time. An orthogonal array L9(3) was selected. 4 Perform orthogonal experiments.

[0123] Step 1: Take 100ml of sample from each test point, add a certain amount of polyether (1% concentration) and Siberon (0.5% concentration) while stirring at room temperature, and stir for a certain time (1-3 hours).

[0124] Step 2: Filtration. The desiliconizing solution is extracted with a kerosene solution of 0.1M N-235 + 0.5% (V / V) mixed alcohols (C7-C9), with a ratio of O / A = 1. After contact for 3 minutes, the solution is allowed to stand and separate into layers.

[0125] Step 3: Measure the stratification time and observe the stratification phenomenon.

[0126] The test results are shown in Table 4. Figure 2 .

[0127] Table 4 Calculation Table of Experimental Combination Results

[0128]

[0129] Note: ∞ indicates that the resulting emulsion is relatively stable.

[0130] The results showed that the main factors affecting the extraction desiliconization rate and extraction stratification time were the amount of Siberon and the amount of polyether, while the stirring time had no significant effect. Adding a certain amount of polyether and Siberon for desiliconization could significantly improve the stratification effect, but neither should be added in excess, especially polyether, which could cause extraction emulsification.

[0131] The optimal experimental conditions obtained from Table 4 are: 200 g / m³ of polyether. 3 溶液 Siberon 200g / m 3 溶液 The stirring time was 3 hours. The results were calculated from Table 4. Figure 2 The optimal overall conditions were determined to be: polyether dosage 200 g / m³. 3 Solution, Siberian dosage 200g / m³ 3 溶液 Stirring time: 1 hour.

[0132] The experimental results show that a polyether dosage of 100 g / m³ is optimal. 3 溶液 Siberian dosage 200g / m 3 溶液 Stirring for 1 hour provides better conditions for desilicification and demulsification.

[0133] 2) Extraction test

[0134] After the first qualified solution was treated with polyether-Sibron to remove SiO2, uranium was extracted with N-235. Organic phase composition (N-235 concentration and mixed alcohol concentration) selection tests were conducted, and the uranium distribution equilibrium-operation curve and countercurrent extraction equilibrium stage were determined. The condition selection test and distribution equilibrium curve determination were performed using a 100ml separatory funnel. The extraction equilibrium stage test was conducted countercurrently in a single-stage circular extraction tank with a volume of 480ml (20ml mixing chamber, 460ml clarification chamber).

[0135] Reagent: N-235, 2.4 mg / g, specific gravity

[0136] Mixed alcohols: C7-C9, boiling range 170-240℃

[0137] Sulfonated kerosene: Industrial grade.

[0138] (1) Organic phase composition selection test

[0139] Experimental conditions: Aqueous phase U = 0.383 g / L (silicon removal solution).

[0140] Organic phase: N-235 of different concentrations + mixed alcohols of different concentrations + sulfonated kerosene

[0141] Compared to: O / A = 1

[0142] Contact time: 2 minutes.

[0143] The test results are listed in Table 5.

[0144] Table 5. Effect of organic phase composition on uranium partition ratio

[0145]

[0146] The results showed that the uranium partition ratio increased with increasing amine concentration and decreased with increasing alcohol concentration. For a solution containing U = 0.383 g / L, a N-235 concentration of 0.05 M was sufficient for extraction. To reduce the loss of extractant dispersion in the raffinate aqueous phase and to avoid the formation of a third phase during the subsequent acid washing of the saturated organic phase, a kerosene solution with an organic phase composition of 0.05 M N-235 + 2 (v)% mixed alcohols was selected.

[0147] (2) Determination of the equilibrium stage of countercurrent extraction

[0148] Test conditions:

[0149] Aqueous phase: U = 0.383 g / L

[0150] Organic phase: 0.05m N-235 + 2(V)% mixed alcohol + kerosene, equilibrium ratio O / A = 1 / 5, contact ratio O / A > 1.

[0151] Contact time: 2 minutes.

[0152] The test results are shown in Table 6.

[0153] Table 6 Results of Countercurrent Extraction Equilibrium Stage Determination

[0154]

[0155] Extraction equilibrium-operation curves are shown in [reference needed]. Figure 3 As shown in the figure, using an organic phase consisting of 0.05 mM N-235 + 2(V)% mixed alcohol + kerosene to extract uranium from an initial aqueous phase containing U = 0.383 g / L, and based on an operating curve with a slope of 5, it can be inferred that three theoretical stages can reduce the uranium content in the raffinate aqueous phase to less than 0.005 g / L. Table 6 shows the actual measured number of countercurrent extraction stages, which is basically consistent with the theoretical number. If four-stage countercurrent extraction is used, the final raffinate aqueous phase U < 1 g / L, and the uranium extraction rate can reach 99.7%.

[0156] 3) Uranium production by crystallization back-extraction

[0157] Under the conditions selected in the extraction experiment, the saturated organic phase obtained by four-stage countercurrent extraction was washed once with sulfuric acid water (pH=1.5, O / A=10 / 1). The organic phase contained 1.950 g / L of uranium. Uranium was back-extracted from N-235, and then crystallization back-extraction was performed using ammonium carbonate to directly prepare uranium products. Product analysis is listed in Table 7.

[0158] Table 7 Results of Uranium Product Quality Analysis

[0159] uranium 46.66％ iron ≤70 Potassium + Sodium 50 aluminum ≤50 sulfate / Tungsten ≤1.6 boron ≤0.5 cobalt ≤1.6 chromium ≤17 molybdenum ≤5 copper ≤0.6 vanadium ≤5 manganese ≤1.9 cadmium ≤0.3 nickel ≤6 magnesium ≤19 silicon ≤165

[0160] 3. Comprehensive recycling of thorium, titanium, and zirconium

[0161] (1) The comprehensive recovery of thorium, titanium, and zirconium is carried out from the first qualified solution in the raffinate aqueous phase after uranium extraction with N-235. An economical and simple phosphate precipitation method is selected. Thorium, titanium, and zirconium are initially precipitated as phosphate concentrates.

[0162] The pH value for ferrous phosphate precipitation is later than that for thorium, titanium, and zirconium phosphate precipitation. Iron filings are used to pre-precipitate the Fe in the solution. 3+ Reduced to Fe 2+ Then, thorium, titanium, and zirconium phosphates are precipitated.

[0163] (2) Reducing solution: Th = 0.402 g / L, TiO2 = 2.950 g / L, Zr = 1.220 g / L, pH = 1.15, redox potential = 250 mV (apparent reading)

[0164] Reagents: NH4OH, Cl, H3PO4, AR, industrial Siberian blend (0.2%)

[0165] (3) Test methods

[0166] Orthogonal experimental design was employed. The orthogonal array L was selected. 16 (4 2 ×2 9 Experiments were conducted to determine the amount of phosphoric acid used, the pH value of precipitation, and the stirring time.

[0167] Step 1: Take 50 ml of the reducing solution at each test point, adjust the pH value with ammonium water, keep the temperature constant, add H3PO4 and stir for a timer.

[0168] Step 2: Add 100g / m³ of Siberian Brilliance 5 minutes before stopping stirring. 3 溶液 Filtration. Analysis of the filtrate revealed thorium, titanium, and zirconium.

[0169] (4) The results showed that the optimal combination of Th, TiO2 and Zr was 3 g / L of phosphoric acid, pH of precipitation = 3.0-3.5, and stirring at room temperature for 30 minutes.

[0170] The optimal precipitation conditions determined above were used to conduct a scale-up verification experiment. The mother liquor and precipitate were dried at 105℃ and then sent for analysis. The experimental results are shown in Tables 8 and 9.

[0171] The experimental results show that the precipitation of thorium, titanium, and zirconium is relatively complete. The precipitation rates are: Th = 97.3%, TiO2 = 97.9%, and Zr = 99.7%. This precipitate can be used as raw material for the next step of thorium, titanium, and zirconium recovery.

[0172] Table 8 Results of the Expanded Validation Test

[0173]

[0174] Table 9. Chemical analysis results of phosphate precipitates

[0175] content 0.0096 2.59 19.81 0.19 7.75 2.81 3.14 2.34 12.50

[0176] 4. Comprehensive recycling of thorium and rare earth elements

[0177] (1) The comprehensive recovery of thorium and rare earth elements was carried out in the second qualified solution. The content of other impurities in the solution was not high except for thorium and rare earth elements. The initial concentration was carried out directly by neutralization precipitation to obtain crude hydroxide product containing thorium and rare earth elements.

[0178] (2) Test methods

[0179] Step 1: Take the second qualified solution, add NH4OH to neutralize to pH=8, and stir at 15℃ for 10 minutes.

[0180] Step 2: Add 20g / m² of Siberian lactone 3 溶液 Filtration followed by flocculation.

[0181] Step 3: The mother liquor and precipitate are dried at 105℃.

[0182] The analysis results are shown in Tables 10 and 11.

[0183] Table 10 shows that thorium can achieve a precipitation rate of 99.2%, and rare earth elements can achieve a precipitation rate of 89.1%. Table 11 shows that the crude hydroxide product has a high content of thorium and rare earth elements, and can be used as a raw material for thorium and rare earth extraction; uranium is also enriched in the crude product.

[0184] Table 10 Results of hydroxide precipitation test

[0185]

[0186] Table 11 Results of multiple chemical analyses of hydroxide products

[0187] content(%) 8.50 0.259 47.20 1.64 1.09 13.14

[0188] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0189] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for comprehensive recovery of uranium, thorium, titanium and zirconium and rare earths from green-bed silicate cerite-titanite, characterized in that, Includes the following steps: Step S1: Grind the green layer cerium-titanium silicate ore to obtain a coarse ore with a diameter of -1 to 0 mm; wherein, the coarse ore with a diameter of -0.074 to 0 mm is used as ore slime and fed into the mixed concentrate. Coarse ore with a diameter of -1 to +0.074 mm enters the next step for two-stage magnetic separation; Step S2: Use a magnetic field to perform two-stage magnetic separation on the coarse ore of -1 to +0.074 mm to obtain mixed concentrate; Step S3: The mixed concentrate is acid-treated and leached to obtain the first qualified solution; the unleached portion is sequentially subjected to the first four-stage countercurrent washing, alkali transformation, acidification, and the second countercurrent washing to obtain the second qualified solution. Step S4: After the first qualified solution undergoes desiliconization and demulsification treatment, it is extracted, crystallized, and back-extracted to obtain uranium products. The raffinate aqueous phase is then precipitated with phosphoric acid to obtain thorium, titanium, and zirconium precipitates. The second qualified solution is added with ammonia and polyacrylamide solution, reacted, and then filtered to obtain crude products of thorium and other rare earth hydroxides.

2. The method for comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layered cerium-titanium ore according to claim 1, characterized in that, Step S2 specifically includes: The first-stage magnetic separation of coarse ore of -1 to +0.074 mm is carried out using a magnetic field with a magnetic field strength of 10,000 to 11,000 Oersted. The ore that passes through is used as concentrate and enters the mixed concentrate. A second-stage magnetic separation is performed on the ore that fails to pass through a magnetic field with an intensity of 12,000 to 13,000 Oersted. The portion that passes through enters the mixed concentrate, while the ore that fails through becomes tailings.

3. The method for comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layered cerium-titanium ore according to claim 2, characterized in that, In step S2: a magnetic field with a magnetic field strength of 10500~10700 Oersted is used to perform the first-stage magnetic separation on the coarse ore of -1+0.074mm.

4. The method for comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layered cerium-bearing borosilicate ore according to claim 1, characterized in that, Step S3 specifically includes: Step S3-1: Based on the quality of the mixed concentrate, add 2% calcium fluoride, 2.0% MnO2, and 22.0% H2SO4 to the mixed concentrate and heat at 120℃ for 2 hours. Step S3-2: Add 3.0% sulfuric acid and heat at 80℃ for 2 hours; leach out to obtain the first qualified solution; Step S3-3: The unleached portion is washed with a sulfuric acid solution of pH=1 and water, wherein the volume ratio of sulfuric acid solution to water is 1:1.

2. The resulting washing solution is returned to step S3-2 for further preparation of the first qualified solution. The washed solid is then alkali-converted by adding an aqueous solution of NaOH at pH=9, wherein the volume ratio of NaOH to water is 1:1.

2. Then, 0.5% H2SO4 is added for acidification to obtain the second qualified solution. The solid after alkali transformation and acidification is mixed with sulfuric acid solution at pH 1.5 and water, with a volume ratio of sulfuric acid solution to water of 1:1.

2. The washing liquid is returned to prepare a second qualified solution; the solid after washing is discarded as tailings.

5. The method for comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layered cerium-titanium ore according to claim 1, characterized in that, In step S4, the desiliconization and demulsification process specifically includes: Add polyether solution and polyacrylamide solution to the first qualified solution, stir, filter, and use the filtrate for extraction; The mass percentage concentration of the polyether solution is 1%, and the dosage is 100 g / m 3 The mass percentage concentration of the polyacrylamide solution is 0.5%, and the dosage is 200 g / m 3 .

6. The method for comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layered cerium-titanium ore according to claim 5, characterized in that, In step S4, the extraction specifically includes: The filtrate was added to an organic phase for four-stage countercurrent extraction. The organic phase consisted of a sulfonated kerosene solution containing 0.05 M N-235 and 2 vol% mixed alcohols. The equilibrium ratio O / A = 1 / 5, while the contact ratio O / A > 1; Contact time: 2 minutes.

7. The method for comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layered cerium-titanium ore according to claim 6, characterized in that, In step S4, the crystallization back-extraction specifically includes: The saturated organic phase obtained by the four-stage countercurrent extraction is washed once with sulfuric acid water at pH 1.5, with an O / A ratio of 10 / 1. Then, uranium is back-extracted from N-235 using ammonium carbonate or ammonium sulfate for crystallization back-extraction to obtain the uranium product.

8. The method for comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layered cerium-titanium ore according to claim 1, characterized in that, In step S4, the pH of the raffinate is adjusted with ammonia, H3PO4 is added to pH=3.0-3.5, the mixture is stirred for 0.5 hours, and polyacrylamide solution is added 5 minutes before the stirring stops. The mixture is then filtered to obtain precipitates of thorium, titanium and zirconium. The polyacrylamide solution is used in an amount of 100 g / m 3 .

9. The method for comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layered cerium-titanium ore according to claim 8, characterized in that, Before adjusting the pH value of the raffinate aqueous phase with ammonia, iron is added, which is reduced to Fe 3+ in the solution 2+ .

10. The method for comprehensive recovery of uranium, thorium, titanium, zirconium, and rare earth elements from green-layered cerium-titanium ore according to claim 1, characterized in that, In the step S4, the second qualified solution is neutralized to pH=8 by adding ammonia water, stirred for 10 minutes at 15°C, and then 20 g / m of polyacrylamide solution is added. 3 Filtration after flocculation; The mother liquor and precipitate were dried at 105°C to obtain crude products of thorium and other rare earth hydroxides.

Images