CN115710648A

CN115710648A - Method for extracting uranium and thorium from green-layer silico-cerium-titanium ore

Info

Publication number: CN115710648A
Application number: CN202110964175.4A
Authority: CN
Inventors: 张振强; 周舰
Original assignee: Nuclear Industry Brigade 243; Cnnc 240 Institute
Current assignee: Nuclear Industry Brigade 243; Cnnc 240 Institute
Priority date: 2021-08-21
Filing date: 2021-08-21
Publication date: 2023-02-24
Anticipated expiration: 2041-08-21
Also published as: CN115710648B

Abstract

The invention relates to the field of ore mining and metallurgy, in particular to a method for extracting uranium and thorium from green-layer silico-cerium-titanium ore. The method comprises the following steps: grinding the green-layer silicon-cerium-titanium ore to prepare a coarse ore with the particle size of-1-0 mm; wherein-0.074-0 mm coarse ore is used as ore mud to enter the bulk concentrate; carrying out two-stage magnetic separation on the crude ore with the grain size of-1 +0.074mm in the next step; carrying out first-stage magnetic separation on the coarse ore with the diameter of-1 +0.074mm by utilizing the magnetic field with the magnetic field intensity of 10000-11000 oersted, and taking the passing ore as concentrate to enter mixed concentrate; carrying out secondary magnetic separation on the ores which do not pass through by using a magnetic field with the intensity of 12000-13000 oersted, and enabling the passing parts to enter the bulk concentrate; carrying out countercurrent leaching on the bulk concentrate to extract uranium and thorium in the bulk concentrate; and (3) adding alkali into the leached residues for treatment, and then reacting with dilute sulfuric acid to extract thorium in the leached residues. The uranium is leached, meanwhile, the thorium is comprehensively recovered, and the leaching rate of the uranium and the thorium is high.

Description

Method for extracting uranium and thorium from green-layer silico-cerium-titanium ore

Technical Field

The invention relates to the field of ore mining and metallurgy, in particular to a method for extracting uranium and thorium from green-layer silico-cerium-titanium ore.

Background

The Liaoning Fengcheng racing horse alkaline uranium deposit is a comprehensive deposit of large-scale uranium, thorium and rare earth elements, is unique in China and is rare in the world. Since the discovery of the last 70 th century, this deposit has attracted widespread attention in the uranium mine geology and mining community. Some leaching tests are carried out at that time, but the uranium leaching rate and the comprehensive utilization rate of other ore species are difficult to solve due to technical reasons.

Uranium racing deposits are produced in alkaline rocks. The main uranium ore type is a green-layer cerite type mineralization produced in grass green neon syenite. It constitutes the main body of a large comprehensive deposit of uranium racetrack, thorium, rare earth, niobium. The industrial mineral is green layer silicon cerium titanium and its altered mineral in different degrees. The uranium content is changed between 0.05 percent and 0.1 percent, the thorium content is changed between 0.15 percent and 0.4 percent, and the cerium group rare earth element and the niobium content reach the industrial requirements.

The green-layer cerite is a less common uranium mineral type in the world. Because most minerals belong to aluminosilicate or ferrosilicate types and contain rare earth, thorium, niobium, tantalum and other components, uranium minerals are difficult to leach, and when a conventional acid method is adopted for leaching, the acid consumption is high, the leaching rate is low, and solid-liquid separation of ore pulp after leaching is difficult.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method for extracting uranium and thorium from the green-layer silico-cerium-titanium ore is provided, uranium is leached, thorium is comprehensively recovered, and the leaching rate of uranium and thorium is high.

The invention provides a method for extracting uranium and thorium from a green-layer silico-cerium-titanium ore, which comprises the following steps:

step S1: grinding the green-layer silicon-cerium-titanium ore to prepare a coarse ore with the thickness of-1 to 0 mm; wherein-0.074-0 mm coarse ore is used as ore mud to enter the bulk concentrate;

carrying out two-stage magnetic separation on the coarse ore with the diameter of-1 +0.074mm in the next step;

step S2: carrying out first-stage magnetic separation on coarse ore with the magnetic field intensity of 10000-11000 oersted and the size of-1 +0.074mm, and feeding the passing ore serving as concentrate into bulk concentrate;

performing secondary magnetic separation on the non-passing ore by using a magnetic field with the strength of 12000-13000 oersted, wherein the passing part enters the mixed concentrate, and the non-passing ore is tailings;

and step S3: carrying out countercurrent leaching on the bulk concentrate to extract uranium and thorium in the bulk concentrate;

and step S4: and (4) adding alkali into the leaching residue obtained in the step (S3), and then reacting with dilute sulfuric acid to extract thorium in the leaching residue.

Preferably, in step S2: the first-stage magnetic separation is carried out on the coarse ore with the thickness of-1 +0.074mm by utilizing the magnetic field intensity of 10500-10700 oersted.

Preferably, the step S3 specifically includes:

adding sulfuric acid, calcium fluoride and manganese dioxide into the mixed concentrate, stirring, fully reacting, adding water, sulfuric acid and manganese dioxide for secondary reaction, and filtering after the secondary reaction is finished; collecting the filtrate;

adding an acid solution into the obtained filter residue, stirring, and pulping for 2-5 times;

and flushing leaching residues.

Preferably, the particle size of the bulk concentrate is-0.417 mm to-0.074 mm.

Preferably, based on the quality of the bulk concentrate, adding 22% of sulfuric acid, 3% of calcium fluoride and 1% of manganese dioxide into 100g of bulk concentrate with the particle size of-0.208 mm, wherein the liquid-solid ratio of the sulfuric acid to the ore is 1.2:1, stirring and reacting for 2 hours at the temperature of 120 ℃.

Preferably, 200ml of water, 3% sulfuric acid and 1% manganese dioxide are added, and the secondary reaction is carried out at 80 ℃ for 2 hours.

Preferably, the step S4 specifically includes:

adding ammonium hydroxide with the mass concentration of 25% into 100g of the leaching residue obtained in the step S3, stirring, fully reacting and filtering; collecting the filtrate;

acidifying the filter residue with 0.5-1% sulfuric acid, washing with acidified water with pH value of 1.5 for 3-5 times, stirring for 15 minutes during each water washing, and filtering; collecting filter residues;

leaching the filter residue with water, and retaining the tailings.

Preferably, in the step S4,

adding 0.8-1.8 ml of 25% ammonium hydroxide into 100g of leaching residues in the step S3 with the solid-to-liquid ratio of 1.2; the filtrate was collected.

Preferably, in the step S4,

adding 1ml of 25% ammonium hydroxide into 100g of leaching residue in the step S3 with the solid-to-liquid ratio of 1.2; the filtrate was collected.

Preferably, in the step S4,

acidifying the filter residue with 0.5% sulfuric acid, washing with acidified water with the pH value of 1.5 for 3-5 times, stirring for 15 minutes during each water washing, and then filtering; and collecting filter residues.

Compared with the prior art, the method for extracting uranium and thorium from the green-layer silico-cerite ore firstly carries out dry magnetic separation to obtain the bulk concentrate, and carries out countercurrent leaching on the bulk concentrate to leach out uranium and thorium; and (3) converting the countercurrent leaching residue by adopting conversion treatment to convert sulfuric acid double salt of thorium into hydroxide, and then carrying out dilute sulfuric acid treatment to further extract thorium. According to the invention, thorium is comprehensively recovered while uranium is leached, and the uranium leaching rate is high.

Drawings

FIG. 1 shows a flow chart of dry magnetic separation.

Detailed Description

For a further understanding of the invention, embodiments of the invention are described below in conjunction with the examples, but it should be understood that these descriptions are included merely to further illustrate features and advantages of the invention, and are not intended to limit the invention.

The embodiment of the invention discloses a method for extracting uranium and thorium from green-layer silico-cerium titanium ore, which comprises the following steps:

step S1: grinding the green-layer silicon-cerium-titanium ore to prepare a coarse ore with the thickness of-1 to 0 mm; wherein, coarse ore with the thickness of-0.074-0 mm is used as ore mud to enter the mixed concentrate;

carrying out two-stage magnetic separation on the crude ore with the grain size of-1 +0.074mm in the next step;

step S2: carrying out first-stage magnetic separation on the coarse ore with the diameter of-1 +0.074mm by utilizing the magnetic field with the magnetic field intensity of 10000-11000 oersted, and taking the passing ore as concentrate to enter mixed concentrate;

According to the invention, the ore is first subjected to a dry magnetic separation. Specifically, the method comprises the following steps:

step S2: carrying out primary magnetic separation on a coarse ore with the thickness of-1 +0.074mm by utilizing a magnetic field with the magnetic field intensity of 10000-11000 oersteds, preferably 10500-10700 oersteds and more preferably 10600 oersteds, and taking the passed ore as a concentrate to enter a mixed concentrate;

and carrying out secondary magnetic separation on the non-passing ore by using a magnetic field with the strength of 12000-13000 oersted, preferably 12000 oersted, wherein the passing part enters the bulk concentrate, and the non-passing ore is tailings. The non-passing tailings are discarded.

After the bulk concentrate is obtained, carrying out countercurrent leaching on the bulk concentrate, specifically:

and step S3: and (4) carrying out countercurrent leaching on the bulk concentrate to extract uranium and thorium in the bulk concentrate.

The step S3 specifically includes:

adding an acidic solution into the obtained filter residue, stirring, and pulping for 2-5 times;

and flushing leaching residues.

The particle size of the bulk concentrate is preferably-0.417 mm to-0.074 mm, more preferably-0.208 mm.

Preferably, based on the mass of the bulk concentrate, adding 22% of sulfuric acid, 3% of calcium fluoride and 1% of manganese dioxide into 100g of bulk concentrate with the particle size of-0.208 mm, wherein the liquid-solid ratio of the sulfuric acid to the ore is 1.2:1, stirring and reacting for 2 hours at the temperature of 120 ℃.

22% sulfuric acid refers to the addition amount of sulfuric acid which is 22% of the mass of the bulk concentrate; the meaning of 3% calcium fluoride and 1% manganese dioxide are similar, and both refer to the addition amount taking the bulk concentrate as a standard.

Then, 200ml of water was added, and 3% sulfuric acid and 1% manganese dioxide were added to conduct a secondary reaction at 80 ℃ for 2 hours.

3% sulfuric acid and 1% manganese dioxide are both added in the amount based on the bulk concentrate.

Adding an acidic solution into the obtained filter residue, stirring for 15 minutes, and pulping for 2-5 times, preferably 3 times;

and washing the leached residues by tap water.

And further carrying out alkali conversion on the obtained leaching residue to extract thorium in the leaching residue. The method specifically comprises the following steps:

The mass percentage concentration of the dilute sulfuric acid is less than 70 percent.

Preferably, the step S4 specifically includes:

adding 0.8-1.8 ml of ammonium hydroxide with the mass concentration of 25% into the leaching residue in the step S3 with the solid-to-liquid ratio of 1.2, stirring for 0.25-1 hour, fully reacting and filtering; collecting the filtrate;

acidifying the filter residue with 0.5-1% sulfuric acid, washing with acidified water with pH value of 1.5 for 3-5 times, stirring for 15 minutes during each water washing, and then filtering; collecting filter residues;

leaching filter residues with water, and keeping tailings.

0.5-1% of sulfuric acid refers to adding 0.5-1% of sulfuric acid by taking the mass of filter residue as a standard.

More preferably, 4ml of ammonium hydroxide with the mass concentration of 25% is added into 100g of leaching residue in the step S3 with the solid-to-liquid ratio of 1.2, the mixture is stirred for 0.25 hour, and the mixture is filtered after full reaction; collecting the filtrate;

acidifying the filter residue with 0.5% sulfuric acid, washing with acidified water with pH of 1.5 for 3 times, stirring for 15 min each time, and filtering; collecting filter residues;

leaching filter residues with water, and keeping tailings.

For further understanding of the present invention, the following examples are given to illustrate the extraction of uranium and thorium from a green-layer cerite titanium ore, and the scope of the present invention is not limited by the following examples.

Example 1

(I) mineral separation

The ore has more ore species. The main minerals comprise feldspar (accounting for about 40%), nepheline (accounting for about 2%), neon stone, sodalite (accounting for about 25%), cerite and the like. The secondary mineral is selected from emeraldine, allolite, blende, calcium pindolite, cancrinite, uranium thorite, and natrolite; and small amount of TiNb-Ca-Ce ore, na-Zr ore, fluorite, uraninite, siu-Ca-Mg ore and metal sulfide ore. The main industrially useful minerals are cerite and its altered products.

100kg of cerite is collected from the racehorse deposit, ground and reduced.

1. Dry magnetic separation

Step 1: grinding: the uranium grade of the ore is 0.055%, and the thorium grade is 0.171%. The raw ore is ground to 1-0 mm by a rod mill.

Step 2: screening: the part of-0.074-0 mm enters the bulk concentrate as slime. The yield of the concentrate is 71.17%, the uranium grade is 0.073%, and the thorium grade is 0.226%.

And step 3: and carrying out two-stage magnetic separation on a part of-1 + 0.074mm.

(1) First-stage magnetic separation: the magnetic field intensity is 10600 oersted (138T-C EPM single-roller magnetic separator), and part of the ore passing through enters the mixed concentrate as the concentrate. The non-passing portion of the ore is subjected to a second stage of magnetic separation as shown in figure 1.

(2) Second-stage magnetic separation, in which the magnetic field strength was 12000 Oe (138T-C sulfate M single-roll magnetic separator). Part of the ore enters the bulk concentrate as the concentrate. The part of the ore which does not pass through becomes tailing waste (the uranium grade of the tailing is 0.0098%, and the thorium grade of the tailing is 0.036%).

2. Magnetic concentrate particle size selection

From the particle size test of the magnetic concentrate, the optimum particle size of-0.208 mm was selected as shown in table 1.

Table 1 particle size test of magnetic concentrates

Countercurrent leaching of uranium thorium from (II) bulk concentrate

1. Leaching of uranium thorium from bulk concentrate

The test conditions and method steps are as follows:

step 1: adding 22% of sulfuric acid, 30% of calcium fluoride and 10% of manganese dioxide into 100g of mixed concentrate with the particle size of-0.208 mm, wherein the liquid-solid ratio of the sulfuric acid to the ore is 1.2:1, stirring.

And 2, step: baking at 120 deg.C for 2 hr, adding 200ml water, adding 30% sulfuric acid, and 10% manganese dioxide.

And 3, step 3: stirring and leaching in a constant temperature water bath kettle at 80 ℃ for 2 hours, and filtering.

And 4, step 4: 200ml of an acidic solution having a pH of 1.5 was added to the residue, and the mixture was stirred for 15 minutes. This procedure was repeated three times.

And 5:200ml tap water was rinsed once. Tailings were obtained and the analytical results are shown in table 2.

TABLE 2 results of countercurrent leaching test

As can be seen from the table, the leaching rate of uranium is 75.12% and the leaching rate of thorium is 35.27% in the countercurrent test.

2. Further extraction of thorium in tailings by alkali conversion

In order to improve the leaching rate of thorium, the countercurrent leaching tailings are subjected to alkali conversion treatment to convert sulfuric acid double salts of thorium in the residues into hydroxides, and then dilute sulfuric acid treatment is carried out to further extract thorium. The method specifically comprises the following steps:

(1) Ammonium hydroxide dosage test

Step 1: taking 100g of countercurrent leaching residue, wherein the liquid-solid ratio is 1.2:1. the mass concentration of the ammonium hydroxide is 25 percent, the dosage is 0.8ml respectively, and the pH is not less than 8;1ml of pH =9;1.8ml, pH =10.

And 2, step: stirred for 15 minutes and the filtrate was discarded.

And step 3: and adding sulfuric acid with the mass percent of 1% of the filter residue into the filter residue for acidification.

And 4, step 4: three times with acidified water pH =1.5, filtered with 15 minutes stirring each time, without retaining the filtrate.

And 5: and rinsing with tap water for the fourth time. Tailings were obtained and the analytical results are shown in table 3.

Table 3 ammonium hydroxide dosage test table

Note: total leaching rate = (concentrate content-tailings content)/concentrate content

From this, pH =9 is optimal.

(2) Test for amount of acidified sulfuric acid

The dosage of the acidified sulfuric acid is 5 percent and 10 percent of the mass of the countercurrent leaching residue respectively, and other conditions are the same as those in the step (1). The results are shown in Table 4.

Table 4 acidified sulfuric acid dosage test table

As can be seen from the table, the amount of sulfuric acid used for the acidification was preferably 5%.

(3) Alkali conversion time test

Ammonium hydroxide was added to bring the pH =9. Acidifying with 5% sulfuric acid. The conversion time was 15 minutes, 30 minutes and 1 hour, and the other conditions were the same as in (2). The results are shown in Table 5.

TABLE 5 alkali conversion time test Table

From the table, the conversion time of 15 minutes is optimal.

(III) extended validation experiment

According to the selected test conditions, 19kg of mixed concentrate subjected to magnetic separation is taken for carrying out an expansion experiment, and finally, 3 times of sampling analysis are carried out on tailings. The results are shown in Table 6.

TABLE 6 analysis of the results of the countercurrent Leaching test

The grade of uranium in the tailings is 0.0147%, and the grade of thorium is 0.065%. The leaching rate of uranium is 80.74 percent, and the leaching rate of thorium is 71.24 percent.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended 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 extracting uranium and thorium from green-layer silico-cerium-titanium ore is characterized by comprising the following steps:

2. The method for extracting uranium and thorium from a green-layer Ceramium silicate titanium ore according to claim 1, wherein in the step S2: the first-stage magnetic separation is carried out on the coarse ore with the thickness of-1 +0.074mm by utilizing the magnetic field intensity of 10500-10700 oersted.

3. The method of claim 1, wherein the step S3 specifically comprises:

and washing the leaching residue.

4. The method for extracting uranium and thorium from a green-layer silico-cerium titanium ore according to claim 3, wherein the particle size of the bulk concentrate is-0.417 mm to-0.074 mm.

5. The process of claim 3, wherein the mass of the bulk concentrate is taken as a standard, 22% sulfuric acid, 3% calcium fluoride and 1% manganese dioxide are added to 100g of the bulk concentrate with the particle size of-0.208 mm, and the liquid-solid ratio of sulfuric acid to ore is 1.2:1, stirring and reacting for 2 hours at the temperature of 120 ℃.

6. The process of claim 3, wherein 200ml of water, 3% sulphuric acid and 1% manganese dioxide are added and a secondary reaction is carried out at 80 ℃ for 2 hours.

7. The method of claim 1, wherein the step S4 specifically comprises:

leaching the filter residue with water, and retaining the tailings.

8. The method of claim 7, wherein in step S4,

adding 0.8-1.8 ml of 25% ammonium hydroxide into 100g of leaching residue in the step S3 with the solid-to-liquid ratio of 1.2, stirring, fully reacting and filtering; the filtrate was collected.

9. The method of claim 7, wherein in step S4,

adding 1ml of 25% ammonium hydroxide into 100g of leaching residue in the step S3 with the solid-to-liquid ratio of 1.2, stirring for 0.25-1 hour, fully reacting and filtering; the filtrate was collected.

10. The method of claim 7, wherein in step S4,