A method for ultrasonically assisted copper ion enhanced flotation of severely surface-oxidized pyrite

Abstract

A method for ultrasonically assisted copper ion-enhanced flotation of severely surface-oxidized pyrite is disclosed, comprising ultrasonically assisted pretreatment of severely surface-oxidized pyrite, activation of the pyrite surface with copper ions after partial shedding of the oxide layer, and flotation recovery of the pyrite after copper ion activation. The method utilizes ultrasonic cavitation to partially shed the dense oxide layer on the pyrite surface, exposing active sites that can react with copper ions and a collector. Subsequently, a copper ion solution is added, which adsorbs on the pyrite surface and generates a copper sulfide-like component that facilitates the adsorption of the collector, increasing the hydrophobicity of the pyrite surface and ultimately achieving the purpose of enhanced flotation recovery of severely surface-oxidized pyrite. This method utilizes low ultrasonic power and short ultrasonic time, low reagent dosage, low cost, and a wide range of sources. The method also achieves high copper ion activation efficiency with the assistance of the ultrasonic cavitation effect. Furthermore, the overall process has low operational requirements and strong adaptability, making it highly valuable for the efficient recovery of similar difficult-to-separate pyrites.

Description

Technical Field

[0001] The invention relates to the technical field of sulfide ore flotation recovery, in particular to a method for ultrasonically assisted copper ion-enhanced flotation of severely surface-oxidized pyrite. Background Art

[0002] Pyrite is an important sulfide mineral, commonly used as a primary raw material for sulfur extraction and sulfuric acid production. Furthermore, due to its excellent semiconductor and optical properties, it is also commonly used as an electrode material for thermal and lithium batteries, as well as a non-toxic and inexpensive material in photovoltaic solar panels. However, pyrite's surface is highly susceptible to oxidation during beneficiation and tailings storage, generating large amounts of acidic mine drainage. If not effectively recovered, it will inevitably cause serious harm to surrounding soil, crops, and organisms in water bodies.

[0003] Flotation is one of the most common methods for recovering pyrite. However, severe surface oxidation of pyrite reduces its floatability, making it difficult to recover using conventional collectors. This is because severe surface oxidation produces a large amount of highly hydrophilic iron oxides and hydroxides, which prevent the effective adsorption of collectors on the pyrite surface. Furthermore, oxidation significantly increases the surface solubility of the pyrite, generating a large amount of iron ions that consume the collector in the slurry.

[0004] The most common recovery method for oxidized pyrite is acid pretreatment and activation flotation. This involves adding a certain concentration of sulfuric acid to the slurry and stirring it to dissolve the iron oxides on the pyrite surface, exposing the fresh pyrite surface. Conventional flotation agents are then added for recovery. However, due to the highly acidic slurry, this method can cause severe corrosion to equipment, shortening its lifespan. It also significantly increases the amount of acidic wastewater, further harming the surrounding ecological environment.

[0005] Another common method is to flotate oxidized pyrite using copper ion activation followed by acid pretreatment. However, the copper ion activation efficiency in this method is significantly affected by the solubility of surface oxidation products and the flotation slurry environment, resulting in a low copper ion activation efficiency. Therefore, developing new flotation technologies to efficiently recover severely oxidized pyrite is crucial for both protecting the ecological environment and realizing the resource utilization of pyrite. Summary of the Invention

[0006] In order to overcome the deficiencies of the above-mentioned prior art, the object of the present invention is to provide a method for enhancing the flotation of severely oxidized pyrite with ultrasound-assisted copper ions. The method comprises the following steps: ultrasonically pretreating the severely oxidized pyrite in an early stage to remove part of the oxide layer on the surface of the pyrite, thereby increasing the surface active sites; and then activating the pyrite surface by adding copper ions, making the pyrite surface more susceptible to reacting with a collector, thereby increasing the floatability of the pyrite, and ultimately achieving the purpose of enhancing the efficient flotation recovery of severely oxidized pyrite.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A method for ultrasonically assisted copper ion enhanced flotation of severely surface-oxidized pyrite comprises the following steps:

[0009] Step 1: Ultrasonic-assisted pretreatment of severely oxidized pyrite on the surface:

[0010] The pyrite with a severely oxidized surface is added to water to prepare a slurry of a certain mass concentration; the pyrite slurry is subjected to ultrasonic pretreatment, and then solid-liquid separation is performed to obtain pyrite with a partially detached surface oxide layer and an iron-containing solution;

[0011] Step 2: Activation of copper ions on the surface of pyrite after partial removal of the oxide layer:

[0012] After adding quicklime and a flocculant in sequence to the iron-containing solution obtained in step 1, flocculation precipitation and solid-liquid separation are performed to obtain a clarified liquid; the pyrite obtained in step 1 is added to the clarified liquid to prepare a pyrite slurry of a certain concentration, thereby achieving the purpose of reducing the discharge of acidic wastewater and reusing water resources; after fully stirring the prepared slurry, the pH value of the slurry is adjusted; then, a copper ion solution is added and fully stirred to activate the pyrite;

[0013] Step 3: Flotation recovery of pyrite after copper ion activation:

[0014] Collectors and pine oil are sequentially added to the slurry obtained in step 2, and aeration flotation is performed. The flotation scraping time is controlled, and the foam product is dried and weighed to finally obtain sulfur concentrate.

[0015] In step 1, severe surface oxidation means that a large amount of highly hydrophilic iron oxides are generated on the surface of pyrite after the reaction with O2 and H2O, which are difficult to be recovered by flotation using conventional xanthate collectors.

[0016] In the step 1, the particle size of the pyrite sample is less than 74 μm, and the slurry concentration is within the range of 5% to 20%; during the ultrasonic treatment, the ultrasonic power is 20 to 100 W, and the ultrasonic time is 2 to 10 minutes.

[0017] In the step 1, after the ultrasonic-assisted pretreatment is completed, precipitation and solid-liquid separation are performed, and then the pyrite slurry is re-prepared, and the above operation is repeated for multiple cycles to obtain pyrite that meets the flotation requirements, and then step 2 is performed.

[0018] In the step 1, the number of cycles of precipitation after ultrasonic-assisted pretreatment and solid-liquid separation is 1 to 5 times.

[0019] In the step 2, the amount of quicklime used relative to the raw ore is 50 to 600 g / t.

[0020] In the step 2, the amount of flocculant used relative to the original ore is 10-100 g / t, and the flocculant is an organic flocculant polyacrylamide.

[0021] In the step 2, the concentration of the pyrite slurry is 10% to 20%, and the pH value of the slurry is 3 to 8.

[0022] In the step 2, the copper ion solution is a copper sulfate solution, the amount of copper ions relative to the original ore is 30-200 g / t, and after the copper ions are added, the activation time is 2-10 minutes.

[0023] In the step 3, the collector is at least one of butyl xanthate, dixanthate, and ethyl thiocyanate, the amount of the collector relative to the original ore is 100-300 g / t, the amount of the pine oil emulsion relative to the original ore is 10-100 g / t, and after the collector and the foaming agent are added, the stirring time is 3 minutes and 2 minutes respectively.

[0024] In the step 3, during the aeration flotation, the aeration time is 1-3 minutes, the flotation scraping time is 2-6 minutes, and the flotation scraping time interval is 10 seconds per time.

[0025] Beneficial effects of the present invention:

[0026] The present invention adopts ultrasonic pretreatment to assist copper ions in activating flotation of pyrite with severe surface oxidation, utilizes ultrasonic cavitation effect to make the dense oxide layer on the surface of pyrite fall off partially, to expose active sites that can act with copper ions and collectors, and then adds copper ion solution, adsorbs on the surface of pyrite, and generates copper sulfide-like components, which are conducive to the adsorption of collectors, so that the hydrophobicity of pyrite surface is increased, and finally achieves the purpose of enhanced flotation recovery of surface severely oxidized pyrite. The ultrasonic power used in this method is low, the ultrasonic time is short, the copper sulfate dosage used is low, the source is wide, and the copper ion activation efficiency is high under the auxiliary action of ultrasonic cavitation effect. In addition, the collector used is a conventional xanthate agent, which is low in price, has low overall process operation requirements and strong adaptability, and has strong promotion value for the efficient recovery of the same type of difficult-to-select pyrite. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the embodiments.

[0028] In the following examples, the particle size of the pyrite samples was all below 74 μm.

[0029] The copper sulfate used was analytical grade, and the collector and frother were industrial grade. All reagent solutions used in the experiment were prepared with deionized water to the corresponding concentrations, and the collector solution was prepared and used immediately.

[0030] The foaming agent solution is prepared by dropping pine oil into a volumetric flask containing a certain amount of deionized water, performing ultrasonic emulsification until the pine oil is completely dissolved, and then adjusting the volume to the corresponding scale line to obtain a pine oil emulsion for use.

[0031] Example 1

[0032] A method for ultrasonically assisted copper ion-enhanced flotation of severely surface-oxidized pyrite is disclosed. The method comprises adding severely surface-oxidized pyrite to water to prepare a 10% slurry. The slurry is ultrasonically pretreated at 60W power and for 6 minutes, followed by solid-liquid separation, repeated twice, to obtain pyrite with partially detached surface oxide layers. During the treatment of the iron-containing solution, 300g / t of quicklime and 50g / t of polyacrylamide are used. During copper ion activation, the slurry concentration is 10%, the pH is 5, the copper ion dosage is 100g / t, and the activation time is 3 minutes. Subsequently, butyl xanthate and pine oil emulsion are added in amounts of 200g / t and 60g / t, respectively, and aeration flotation is performed. The flotation froth is scraped for 3 minutes. The resulting foam product is filtered and dried, resulting in a recovery rate of 91.28% for the severely surface-oxidized pyrite.

[0033] Example 2

[0034] A method for ultrasonically assisted copper ion-enhanced flotation of severely surface-oxidized pyrite is disclosed. The method comprises adding severely surface-oxidized pyrite to water to prepare a 20% slurry. The slurry is ultrasonically pretreated at 60W for 2 minutes, followed by solid-liquid separation, repeated twice, to obtain pyrite with partially detached surface oxide layers. During the treatment of the iron-containing solution, 200g / t of quicklime and 50g / t of polyacrylamide are used. During copper ion activation, the slurry concentration is 20%, the pH is 5, the copper ion dosage is 150g / t, and the activation time is 3 minutes. Subsequently, butyl xanthate and pine oil emulsion are added in amounts of 200g / t and 60g / t, respectively, and aeration flotation is performed for 3 minutes. The resulting foam product is filtered and dried, resulting in a recovery rate of 85.19% for the severely surface-oxidized pyrite.

[0035] Example 3

[0036] A method for ultrasonically assisted copper ion-enhanced flotation of severely surface-oxidized pyrite is disclosed. The method comprises adding severely surface-oxidized pyrite to water to prepare a 20% slurry. The slurry is ultrasonically pretreated at a power of 20W for 2 minutes, followed by solid-liquid separation, repeated five times to obtain pyrite with partially detached surface oxide layers. During the treatment of the iron-containing solution, 400 g / t of quicklime and 80 g / t of polyacrylamide are used. During copper ion activation, the slurry concentration is 20%, the pH is 4, the copper ion dosage is 150 g / t, and the activation time is 3 minutes. Subsequently, butyl xanthate and pine oil emulsion are added in amounts of 200 g / t and 60 g / t, respectively, and aeration flotation is performed. The flotation froth scraping time is 5 minutes. The resulting foam product is filtered and dried, resulting in a recovery rate of 34.24% for the severely surface-oxidized pyrite.

[0037] Example 4

[0038] A method for ultrasonically assisted copper ion-enhanced flotation of severely surface-oxidized pyrite is disclosed. The method comprises adding severely surface-oxidized pyrite to water to prepare a 10% slurry. The slurry is ultrasonically pretreated at a power of 60W for 2 minutes, followed by solid-liquid separation, repeated three times, to obtain pyrite with partially detached surface oxide layers. During the treatment of the iron-containing solution, 200 g / t of quicklime and 60 g / t of polyacrylamide are used. During copper ion activation, the slurry concentration is 20%, the pH is 5, the copper ion dosage is 50 g / t, and the activation time is 6 minutes. Subsequently, butyl xanthate and pine oil emulsion are added in amounts of 200 g / t and 60 g / t, respectively, and aeration flotation is performed. The flotation froth scraping time is 5 minutes. The resulting foam product is filtered and dried, resulting in a recovery rate of 73.50% for the severely surface-oxidized pyrite.

[0039] Example 5

[0040] A method for ultrasonically assisted copper ion-enhanced flotation of severely surface-oxidized pyrite is disclosed. The method is the same as Example 1, except that in step 2, the iron-containing solution is not subjected to flocculation and precipitation treatment. That is, the pyrite with partially detached surface oxide layer is directly added to the iron-containing solution for copper ion activation, and flotation is performed after adding a collector and pine oil. Finally, a pyrite concentrate with a recovery rate of 5.61% is obtained.

[0041] Example 6

[0042] A method for ultrasonically assisted copper ion-enhanced flotation of severely surface-oxidized pyrite is disclosed. The method is the same as Example 1, except that during the ultrasonic pretreatment, the ultrasonic power is 100 W. After the ultrasonic treatment, the copper ions are activated, and flotation is performed after adding a collector and pine oil. Finally, a pyrite concentrate with a recovery rate of 75.12% is obtained.

[0043] Example 7

[0044] A method for ultrasonically assisted copper ion-enhanced flotation of severely surface-oxidized pyrite is disclosed. The method is the same as Example 1, except that ultrasonic pretreatment is not performed. After stirring in a flotation tank for 3 minutes, copper ion activation is performed directly. The copper ion dosage is 100 g / t, the activation time is 3 minutes, and flotation is performed after adding a collector and pine oil. Finally, a pyrite concentrate with a recovery rate of 8.64% is obtained.

[0045] Example 8

[0046] A method for ultrasonically assisted copper ion-enhanced flotation of severely surface-oxidized pyrite is disclosed. The method is the same as Example 1, except that ultrasonic pretreatment is not performed. After stirring in a flotation tank for 3 minutes, copper ion activation is performed directly. The copper ion dosage is 200 g / t, the activation time is 3 minutes, and flotation is performed after adding a collector and pine oil. Finally, a pyrite concentrate with a recovery rate of 9.15% is obtained.

Claims

1. A method for ultrasonically assisted copper ion enhanced flotation of severely surface oxidized pyrite, characterized in that: The following steps are included: Step 1: Ultrasonic-assisted pretreatment of severely oxidized pyrite on the surface: The pyrite with a severely oxidized surface is added to water to prepare a slurry of a certain mass concentration; the pyrite slurry is subjected to ultrasonic pretreatment, and then solid-liquid separation is performed to obtain pyrite with a partially detached surface oxide layer and an iron-containing solution; Step 2: Activation of copper ions on the surface of pyrite after partial removal of the oxide layer: After adding quicklime and a flocculant in sequence to the iron-containing solution obtained in step 1, flocculation precipitation and solid-liquid separation are performed to obtain a clarified liquid; the pyrite obtained in step 1 is added to the clarified liquid to prepare a pyrite slurry of a certain concentration; after fully stirring the prepared slurry, the pH value of the slurry is adjusted; and then a copper ion solution is added and fully stirred to activate the pyrite; Step 3: Flotation recovery of pyrite after copper ion activation: Collectors and pine oil emulsion are sequentially added to the slurry obtained in step 2, and aeration flotation is performed. The flotation scraping time is controlled, and the foam product is dried and weighed to finally obtain sulfur concentrate.

2. The method for ultrasonically assisted copper ion enhanced flotation of severely surface oxidized pyrite according to claim 1, characterized in that: In the step 1, the particle size of the pyrite sample is less than 74 μm, and the slurry concentration is within the range of 5% to 20%; during the ultrasonic treatment, the ultrasonic power is 20 to 100 W, and the ultrasonic time is 2 to 10 minutes.

3. The method for ultrasonically assisted copper ion enhanced flotation of severely surface oxidized pyrite according to claim 1, characterized in that: In the step 1, after the ultrasonic-assisted pretreatment is completed, precipitation and solid-liquid separation are performed, and then the pyrite slurry is re-prepared, and the above operation is repeated multiple times to obtain pyrite that meets the flotation requirements, and then step 2 is performed; In the step 1, the number of cycles of precipitation after ultrasonic-assisted pretreatment and solid-liquid separation is 1 to 5 times.

4. The method for ultrasonically assisted copper ion enhanced flotation of severely surface oxidized pyrite according to claim 1, characterized in that: In the step 2, the amount of quicklime used relative to the raw ore is 50-600 g / t.

5. The method for ultrasonically assisted copper ion enhanced flotation of severely surface oxidized pyrite according to claim 1, characterized in that: In the step 2, the amount of flocculant used relative to the original ore is 10-100 g / t, and the flocculant is an organic flocculant polyacrylamide.

6. The method for ultrasonically assisted copper ion enhanced flotation of severely surface oxidized pyrite according to claim 1, characterized in that: In the step 2, the pyrite slurry concentration is 10% to 20%, and the slurry pH value is 3 to 8.

7. The method for ultrasonically assisted copper ion enhanced flotation of severely surface oxidized pyrite according to claim 1, characterized in that: In the step 2, the copper ion solution is a copper sulfate solution, the amount of copper ions relative to the original ore is 30-200 g / t, and after the copper ions are added, the activation time is 2-10 min.

8. The method for ultrasonically assisted copper ion enhanced flotation of severely surface oxidized pyrite according to claim 1, characterized in that: In the step 3, the collector is at least one of butyl xanthate, dixanthate, and ethyl thiocyanate, the amount of the collector relative to the original ore is 100-300 g / t, the amount of the pine oil emulsion relative to the original ore is 10-100 g / t, and after adding the collector and pine oil emulsion, the stirring time is 3 min and 2 min, respectively.

9. The method for ultrasonically assisted copper ion enhanced flotation of severely surface oxidized pyrite according to claim 1, characterized in that: In the step 3, during the aeration flotation, the aeration time is 1-3 minutes, the flotation scraping time is 2-6 minutes, and the flotation scraping time interval is 10 seconds per time.