Beneficiation method of high-quality phosphoric ore pulp for producing hemihydrate-dihydrate phosphoric acid

Abstract

The invention discloses a beneficiation method of high-quality phosphoric ore pulp for producing hemihydrate-dihydrate phosphoric acid, and relates to the technical field of phosphorite beneficiation. The method comprises the following steps: primarily crushing medium-low-grade collophanite, grinding and grading to obtain flotation pulp; after sulfuric acid and a reverse flotation collecting agent are added into flotation pulp for pulp mixing and mineralization, the flotation pulp is pumped into a roughing flotation column for roughing, and roughing concentrate is obtained; the roughing concentrate is subjected to size mixing and pumped into a cyclone set to be subjected to cyclone classification, and sand setting ore pulp with sesquioxide reduced is obtained; carrying out size mixing on the sand setting ore pulp, and pumping the ore pulp into a fine flotation column to obtain fine phosphoric ore pulp; concentrating the concentrated ore pulp through a thickener, pressurizing and filtering, and supplying the concentrated ore pulp to a semi-hydrated-dihydrated phosphoric acid device for use. A flotation column is adopted for roughing, part of sesquioxide in the phosphoric ore pulp is removed through low-pressure rotational flow grading, deep magnesium removal is conducted through a fine selection technology, magnesium oxide in the ore pulp is further reduced, and the phosphoric ore pulp meeting the production requirement of the semi-hydrate-dihydrate phosphoric acid technology is obtained through concentration and filter pressing dehydration of a thickener.

Description

Technical Field

[0001] The present invention relates to the technical field of phosphate ore beneficiation, and particularly relates to a beneficiation method for high-quality phosphate ore pulp used in the production of hemihydrate-dihydrate phosphoric acid. Background Art

[0002] The production of hemihydrate-dihydrate phosphoric acid means producing phosphoric acid by the hemihydrate-dihydrate method, which has high requirements for the quality, grade, and stability of the raw material phosphate ore pulp. With the continuous depletion of phosphate rock resources, the grade of phosphate rock has decreased significantly, and the impurity content has generally increased, making it difficult to directly meet the production requirements of the hemihydrate-dihydrate method. Therefore, it is urgent to develop a beneficiation method for high-quality phosphate ore pulp to obtain high-grade phosphate ore pulp with low magnesium oxide content to meet the production requirements of the hemihydrate-dihydrate method for producing phosphoric acid. Summary of the Invention

[0003] The purpose of the present invention is to provide a beneficiation method for high-quality phosphate ore pulp used in the production of hemihydrate-dihydrate phosphoric acid, so as to solve the problem that existing medium and low-grade collophanite is difficult to meet the production requirements.

[0004] To solve the above technical problems, the present invention adopts the following technical solutions: A beneficiation method for high-quality phosphate ore pulp used in the production of hemihydrate-dihydrate phosphoric acid, characterized by comprising the following steps:

[0005] S1. After the medium and low-grade collophanite is preliminarily crushed, it undergoes wet grinding and classification to obtain a flotation pulp with a concentration of 22-25% and a fineness of -200 mesh of 75%-80%.

[0006] S2. The flotation pulp is pumped into the first pulp stirring tank, sulfuric acid is added at 11-13 Kg / t, then it is pumped into the second pulp stirring tank, and an anti-flotation collector is added at 0.5-0.65 Kg / t. After stirring, adjusting the pulp, and mineralization, it is pumped into a roughing flotation column for roughing to obtain a roughing concentrate, and the top overflow enters the scavenging.

[0007] S3. The roughing concentrate is adjusted to obtain a pulp with a concentration of 24-27% and a pH value of 4.3-4.5, and is pumped into a hydrocyclone group for hydrocyclone classification to obtain a sand pulp with sesquioxide R2O3 reduced to 1.7-2.0%.

[0008] S4. The sand pulp is adjusted to obtain a pulp with a concentration of 24-27% and a pH value of 4.3-4.5, and is pumped into a cleaning flotation column to obtain a cleaned phosphate ore pulp; the top overflow enters the scavenging.

[0009] S5. The cleaned ore pulp is concentrated by a thickener to obtain a high-quality phosphate ore pulp with a concentration of 64-66%, and after pressure filtration, the moisture content is ≤15%, and it is supplied for use in the hemihydrate-dihydrate phosphoric acid device.

[0010] A further technical solution is that the content of P2O5 in the medium and low-grade collophanite described in step S1 is 25.0 - 26.0%, the content of MgO is 3.0 - 3.5%, the content of R2O3 is 2.2 - 2.5%, and the MER value is 0.20 - 0.24.

[0011] A further technical solution is that the reverse flotation collector is a fatty acid soap collector, the pH value is controlled at 4.0 - 4.2 after adding sulfuric acid in S2, and the pH value is controlled at 4.3 - 4.5 after adding the reverse flotation collector.

[0012] A further technical solution is that the roughing flotation column described in step S2 has a specification of φ4.0m×10.0m, the flotation time in the roughing flotation column is 18 min, the flotation pressure is 0.25 - 0.45 MPa, the content of P2O5 in the roughing concentrate is 28.0 - 29.0%, the content of MgO is 1.1 - 1.3%, the content of R2O3 is 2.0 - 2.4%, and the MER value is 0.107 - 0.132.

[0013] A further technical solution is that the hydrocyclone group described in step S3 is composed of 3 φ250mm hydrocyclones in series, the classification pressure is 0.02 - 0.04 MPa, the content of P2O5 in the sand slurry is 28.6 - 29.4%, the content of MgO is 1.1 - 1.3%, the content of R2O3 is 1.6 - 2.0%, and the MER value is 0.092 - 0.115.

[0014] A further technical solution is that the cleaning flotation column described in step S4 has a specification of φ4.0m×10.0m, the flotation time in the roughing flotation column is 25 min, the flotation pressure is 0.25 - 0.45 MPa, the content of P2O5 in the cleaning phosphate ore slurry is 29.5 - 30.5%, the content of MgO < 0.8%, the content of R2O3 is 1.65 - 2.0%, and the MER value is 0.080 - 0.095.

[0015] A further technical solution is that the concentrate after scavenging and the overflow of hydrocyclone classification are concentrated by a thickener and then used in a dihydrate phosphoric acid plant.

[0016] A further technical solution is that the thickener described in step S5 is a φ18.0m ore slurry thickener, and the pressure filtration uses a 60m 2 disc pressure filter.

[0017] A further technical solution is that the content of P2O5 in the high-quality phosphate ore slurry described in step S5 is 29.5 - 30.5%, MgO < 0.8%, and the MER value is 0.08 - 0.09.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] For medium and low-grade collophanite, after grinding, sulfuric acid and a collector are added, and rough selection is carried out using a flotation column. Then, a low-pressure hydrocyclone classification method is used to remove part of the sesquioxide R2O3 in the phosphate slurry, improving the quality of the slurry. Further deep magnesium removal is carried out through a cleaning process (re-selection of rough concentrate), further reducing the magnesium oxide in the slurry, and improving the grade and comprehensive quality of the slurry. Then, thickening by a thickener and dewatering by pressure filtration are carried out to obtain high-quality phosphate slurry that meets the production requirements of the hemihydrate-dihydrate phosphoric acid process. Brief Description of the Drawings

[0020] Figure 1 It is a schematic process flow diagram of the present invention. Detailed Embodiments

[0021] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] The sesquioxide R2O3 mentioned in the present invention refers to the sum of the contents of trioxides in phosphate rock and phosphoric acid, that is, the sum of AL2O3 + Fe2O3.

[0023] Example 1

[0024] A beneficiation method for high-quality phosphate slurry used in the production of hemihydrate-dihydrate phosphoric acid includes the following steps:

[0025] S1. After the medium and low-grade collophanite is preliminarily crushed (particle size less than 25 mm), wet grinding and classification are carried out to obtain a flotation slurry with a concentration of 22% and a fineness of -200 mesh of 80%. During the trial production from April 21st to 28th, 2023, the average quality of the raw medium and low-grade collophanite used in production was: P2O5 25.92%, MgO 3.12%, R2O3 2.33%, and the MER value was 0.210.

[0026] S2. The flotation slurry is pumped into the first slurry stirring tank. After adding sulfuric acid at 11 Kg / t, the pH value is controlled at 4.0 - 4.2. Then it is pumped into the second slurry stirring tank. After adding the reverse flotation collector YP-6 at 0.5 Kg / t, the pH value is controlled at 4.3 - 4.5. After stirring, adjusting the slurry and mineralization, it is pumped into a rough selection flotation column with a specification of φ4.0m × 10.0m for rough selection to obtain rough concentrate, and the top overflow enters the scavenging. The first stirring tank (adding sulfuric acid to adjust pH, stirring for 5 min) and the second stirring tank (adding collector and stirring for 8 min), the tank body model is Φ4600 × 4500, V = 74m 3 , the stirring paddle has double-layer blades, the rotation speed is 61 r / min, the flotation time in the rough selection flotation column is 18 min, and the flotation column air guns are divided into 4 groups, with the single-group gas volume being 110 - 128m 3 / h, with a pressure of 0.25 - 0.45 MPa. The average quality of the rougher concentrate is: P2O5 28.78%, MgO 1.07%, R2O3 2.26%, and the MER value is 0.120.

[0027] S3. Slurry the rougher concentrate to obtain a slurry with a concentration of 27% and a pH value of 4.3 - 4.5, pump it into a hydrocyclone group for hydrocyclone classification, and obtain a sand slurry with sesquioxide R2O3 reduced to 1.7 - 2.0%; the hydrocyclone group consists of 3 series-connected φ250mm hydrocyclones, with a classification pressure of 0.02 - 0.04 MPa. The sand slurry indexes are: P2O5 29.35%, MgO 1.12%, R2O3 1.85%, and the MER value is 0.101.

[0028] S4. Slurry the sand slurry to obtain a slurry with a concentration of 27% and a pH value of 4.3 - 4.5, pump it into a cleaning flotation column with a specification of φ4.0m×10.0m to obtain a cleaned phosphate ore slurry; the top overflow enters the scavenging; no additional collector needs to be added for the re - selection of the concentrate, and the flotation column is aerated for re - separation. The flotation column model is φ4000*100000mm, and each flotation column has a total of 36 air guns, with every 9 air guns divided into 1 group, and the single - group gas volume is 110 - 128 m3 / h, and the pressure is 0.25 - 0.45 MPa. The indexes of the cleaned phosphate ore slurry are: P2O5 30.18%, MgO 0.64%, R2O3 1.89%, and the MER value is 0.084. After the scavenged concentrate and the hydrocyclone classification overflow are concentrated by a thickener, they are used in the dihydrate phosphoric acid device.

[0029] S5. Concentrate the cleaned ore slurry through a thickener to obtain a high - quality phosphate ore slurry with a concentration of 64 - 66%. The concentrated phosphate ore slurry: has a solid content of 64 - 66%, P2O5 30.18%, MgO 0.64%, R2O3 1.89%, and the MER value is 0.084. After pressure filtration, the moisture content ≤15% and it is supplied for use in the semi - water - dihydrate phosphoric acid device. The thickener uses a φ18.0m ore slurry thickener, and the pressure filtration uses 1 set of 60m 2 disc - type pressure filter.

[0030] Example 2

[0031] A beneficiation method for high - quality phosphate ore slurry used in the production of semi - water - dihydrate phosphoric acid, including the following steps:

[0032] S1. After the medium - and low - grade collophanite is preliminarily crushed (particle size less than 25mm), it undergoes wet grinding and classification to obtain a flotation slurry with a concentration of 22% and a fineness of - 200 mesh of 80%; from January to December 2024, the average quality of the medium - and low - grade collophanite raw ore used in production is: P2O5 25.78%, MgO 3.22%, R2O3 2.28%, and the MER value is 0.213.

[0033] S2. The beneficiation pulp is pumped into the first pulp stirring tank. After adding sulfuric acid at 11 Kg / t, the pH value is controlled at 4.0 - 4.2. Then it is pumped into the second pulp stirring tank. After adding the reverse flotation collector YP-6 at 0.5 Kg / t, the pH value is controlled at 4.3 - 4.5. For the first stirring tank (adjusting pH with sulfuric acid and stirring for 5 min) and the second stirring tank (adding collector and stirring for 8 min), the tank model is Φ4600×4500, V = 74 m 3 , the stirring paddle has double layers of blades, the rotation speed is 61 r / min, the flotation time in the rougher flotation column is 18 min, the air guns in the flotation column are divided into 4 groups, and the gas volume of a single group is 110 - 128 m 3 / h, and the pressure is 0.25 - 0.45 MPa. After stirring, adjusting pulp and mineralization, it is pumped into the rougher flotation column with a specification of φ4.0 m×10.0 m for roughing to obtain the rougher concentrate, and the top overflow enters the scavenging. The average quality of the rougher concentrate is: P2O5 28.86%, MgO 1.09%, R2O3 2.22%, and the MER value is 0.115.

[0034] S3. The rougher concentrate is adjusted to obtain a pulp with a concentration of 27% and a pH value of 4.3 - 4.5, and then pumped into the hydrocyclone group for hydrocyclone classification to obtain the sand pulp with sesquioxide R2O3 reduced to 1.7 - 2.0%; the hydrocyclone group is composed of 3 series-connected φ250 mm hydrocyclones, and the classification pressure is 0.02 - 0.04 MPa. The indexes of the sand pulp are: P2O5 29.46%, MgO 1.15%, R2O3 1.91%, and the MER value is 0.104.

[0035] S4. The sand pulp is adjusted to obtain a pulp with a concentration of 27% and a pH value of 4.3 - 4.5, and then pumped into the cleaning flotation column with a specification of φ4.0 m×10.0 m to obtain the cleaned phosphate ore pulp; the top overflow enters the scavenging; no corresponding collector needs to be added for re-election of the concentrate, and the parameters of the flotation column are the same as those of the roughing. The indexes of the cleaned phosphate ore pulp are: P2O5 30.09%, MgO 0.75%, R2O3 1.90%, and the MER value is 0.088. After scavenging, the concentrate and the overflow of the hydrocyclone classification are concentrated by a thickener and then used in the dihydrate phosphoric acid device.

[0036] S5. The cleaned ore pulp is concentrated by a thickener to obtain a high-quality phosphate ore pulp with a concentration of 64 - 66%. The concentrated phosphate ore pulp: the solid content is 64 - 66%, P2O5 30.09%, MgO 0.75%, R2O3 1.90%, and the MER value is 0.088. After pressure filtration, the moisture content ≤ 15% and it is supplied to the semi-hydrate - dihydrate phosphoric acid device for use. The thickener uses a φ18.0 m pulp thickener, and the pressure filtration uses a 60 m 2 disc type pressure filter.

[0037] Example 3

[0038] A beneficiation method for high-quality phosphate rock slurry used in the production of hemihydrate-dihydrate phosphoric acid, comprising the following steps:

[0039] S1. After the medium- and low-grade collophanite is preliminarily crushed (particle size less than 25 mm), it undergoes wet grinding and classification to obtain a flotation slurry with a concentration of 22% and a fineness of -200 mesh of 80%. From January to February 2025, the average quality of the medium- and low-grade collophanite raw ore used in production was: P2O5 25.45%, MgO 3.56%, R2O3 2.15%, and MER value 0.224.

[0040] S2. The flotation slurry is pumped into the first pulp stirring tank. After adding sulfuric acid at 11 Kg / t, the pH value is controlled at 4.0 - 4.2. It is then pumped into the second pulp stirring tank. After adding the reverse flotation collector YP-6 at 0.5 Kg / t, the pH value is controlled at 4.3 - 4.5. After stirring, adjusting the pulp, and mineralization, it is pumped into a roughing flotation column with a specification of φ4.0m × 10.0m for roughing to obtain a roughing concentrate, and the top overflow enters the scavenging. The first stirring tank (adjusting pH with sulfuric acid and stirring for 5 min) and the second stirring tank (stirring with the collector for 8 min), the tank body model is Φ4600×4500, V = 74m 3 , the stirring paddle has double-layer blades, the rotation speed is 61 r / min, the flotation time in the roughing flotation column is 18 min, the flotation column air guns are divided into 4 groups, and the single-group gas volume is 110 - 128m 3 / h, and the pressure is 0.25 - 0.45 MPa. The average quality of the roughing concentrate is: P2O5 28.71%, MgO 1.24%, R2O3 2.11%, and MER value 0.117.

[0041] S3. The roughing concentrate is adjusted to obtain a pulp with a concentration of 27% and a pH value of 4.3 - 4.5, and then pumped into a hydrocyclone group for hydrocyclone classification to obtain a sand slurry with sesquioxide R2O3 reduced to 1.7 - 2.0%; the hydrocyclone group is composed of 3 φ250mm hydrocyclones in series, and the classification pressure is 0.02 - 0.04 MPa. The sand slurry index is: P2O5 29.29%, MgO 1.28%, R2O3 1.75%, and MER value 0.102.

[0042] S4. The sand slurry is adjusted to obtain a pulp with a concentration of 27% and a pH value of 4.3 - 4.5, and then pumped into a cleaning flotation column with a specification of φ4.0m × 10.0m to obtain a cleaned phosphate rock slurry; the top overflow enters the scavenging; no corresponding collector needs to be added for the re-election of the concentrate, and the flotation column parameters are the same as those in the roughing. The index of the cleaned phosphate rock slurry is: P2O5 30.21%, MgO 0.71%, R2O3 1.78%, and MER value 0.082. After the scavenged concentrate and the hydrocyclone classification overflow are concentrated by a thickener, they are used in the dihydrate phosphoric acid device.

[0043] S5. The selected ore pulp is concentrated by a thickener to obtain high-quality phosphate ore with a concentration of 64-66%, solid content: 64-66%, P2O5 30.21%, MgO 0.71%, R2O3 1.78%, MER value 0.082. After pressure filtration, the moisture content is ≤15%, and it is supplied to the hemihydrate-dihydrate phosphoric acid plant for use. The thickener uses a φ18.0m ore pulp thickener, and the pressure filtration uses a 60m 2 disc pressure filter.

[0044] Although the present invention has been described with reference to several illustrative embodiments thereof, it should be understood that those skilled in the art can design many other modifications and embodiments that will fall within the scope of the disclosure of this application. More specifically, within the scope of the disclosure of this application, the accompanying drawings, and the claims, various deformations and improvements can be made to the components or the layout. In addition to the deformations and improvements to the components or the layout, other uses will also be obvious to those skilled in the art.

Claims

1. A beneficiation method for high-quality phosphate rock slurry used in the production of hemihydrate-dihydrate phosphoric acid, characterized in that It includes the following steps: S1. After the medium and low-grade collophanite is preliminarily crushed, it undergoes wet grinding and classification to obtain a flotation pulp with a concentration of 22-25% and a fineness of -200 mesh of 75%-80%. S2. The flotation pulp is pumped into the first pulp stirring tank. After adding sulfuric acid at 11-13 Kg / t, it is pumped into the second pulp stirring tank. After adding an anti-flotation collector at 0.5-0.65 Kg / t, it is stirred, adjusted for pulp, and mineralized, and then pumped into a roughing flotation column for roughing to obtain a roughing concentrate. The top overflow enters the scavenging. S3. The roughing concentrate is adjusted for pulp to obtain a pulp with a concentration of 24-27% and a pH value of 4.3-4.5, and is pumped into a hydrocyclone group for hydrocyclone classification to obtain a sand pulp with the sesquioxide R2O3 reduced to 1.7-2.0%. S4. The sand pulp is adjusted for pulp to obtain a pulp with a concentration of 24-27% and a pH value of 4.3-4.5, and is pumped into a cleaning flotation column to obtain a cleaned phosphate pulp. The top overflow enters the scavenging. S5. The cleaned pulp is concentrated by a thickener to obtain a high-quality phosphate pulp with a concentration of 64-66%, and is pressure-filtered to make the moisture content ≤ 15%, and is supplied for use in a semi-hydrate to dihydrate phosphoric acid device.

2. The beneficiation method of high-quality phosphate rock slurry for semi-hydrate - dihydrate phosphoric acid production according to claim 1, characterized in that: In the medium and low-grade collophanite described in step S1, the P2O5 content is 25.0-26.0%, the MgO content is 3.0-3.5%, the R2O3 content is 2.2-2.5%, and the MER value is 0.20-0.

24.

3. The beneficiation method of high-quality phosphate rock slurry for semi-hydrate - dihydrate phosphoric acid production according to claim 1, characterized in that: The anti-flotation collector is a fatty acid soap collector. After adding sulfuric acid in S2, the pH value is controlled at 4.0-4.2, and after adding the anti-flotation collector, the pH value is controlled at 4.3-4.

5.

4. The beneficiation method of high-quality phosphate rock slurry for semi-hydrate - dihydrate phosphoric acid production according to claim 1, characterized in that: In step S2, the specifications of the roughing flotation column are φ4.0m×10.0m. The flotation time in the roughing flotation column is 18 min, the flotation pressure is 0.25-0.45 MPa. In the roughing concentrate, the P2O5 content is 28.0-29.0%, the MgO content is 1.1-1.3%, the R2O3 content is 2.0-2.4%, and the MER value is 0.107-0.

132.

5. The ore dressing method of high-quality phosphate rock pulp for semi-hydrate - dihydrate phosphoric acid production according to claim 1, characterized in that: In step S3, the hydrocyclone group is composed of 3 series-connected φ250mm hydrocyclones. The classification pressure is 0.02-0.04 MPa. In the sand pulp, the P2O5 content is 28.6-29.4%, the MgO content is 1.1-1.3%, the R2O3 content is 1.6-2.0%, and the MER value is 0.092-0.

115.

6. The beneficiation method of high-quality phosphate rock slurry for semi-hydrate - dihydrate phosphoric acid production according to claim 1, characterized in that: In step S4, the specifications of the cleaning flotation column are φ4.0m×10.0m. The flotation time in the roughing flotation column is 25 min, the flotation pressure is 0.25-0.45 MPa. In the cleaned phosphate pulp, the P2O5 content is 29.5-30.5%, the MgO content < 0.8%, the R2O3 content is 1.65-2.0%, and the MER value is 0.080-0.

095.

7. The beneficiation method of high-quality phosphate rock slurry for semi-hydrate - dihydrate phosphoric acid production according to claim 1, characterized in that: The concentrate after scavenging and the overflow of hydrocyclone classification are concentrated by a thickener and used in the dihydrate phosphoric acid device.

8. The beneficiation method of high-quality phosphate rock slurry for semi-hydrate - dihydrate phosphoric acid production according to claim 1, characterized in that: In step S5, a pulp thickener with a diameter of φ18.0m is used, and a disc pressure filter with a capacity of 60m 2 is adopted.

9. The beneficiation method of high-quality phosphate rock pulp for semi-hydrate - dihydrate phosphoric acid production according to claim 1, characterized in that: In the high-quality phosphate pulp described in step S5, the P2O5 content is 29.5-30.5%, MgO < 0.8%, and the MER value is 0.08-0.09.

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