Application method of fluorite ore flotation inhibitor in calcite-fluorite separation

Abstract

The present invention discloses a method for applying a fluorite flotation inhibitor in calcite-fluorite separation, comprising the following steps: S1. grinding sawdust and then pyrolyzing it under a protective atmosphere, and condensing and collecting the gas in the pyrolysis product to obtain the fluorite flotation inhibitor; S2. grinding the fluorite ore, and then sequentially adding a pH adjuster, the flotation inhibitor and a collector, and performing rough separation to obtain a fluorite rough concentrate and a fluorite rougher tailing; S3. adding the flotation inhibitor to the fluorite rough concentrate, performing fine separation, and obtaining a fluorite concentrate; S4. adding a collector to the fluorite rougher tailing, performing scavenging, and obtaining a fluorite tailing. The flotation inhibitor has a strong selective inhibitory effect on calcite, but has almost no inhibitory effect on fluorite, has a good flotation separation effect, can obtain a fluorite concentrate with high grade and high recovery rate, and has a low preparation cost, is expected to achieve high-value utilization of waste, and has good social, environmental and economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing and relates to an application method of a fluorite ore flotation inhibitor in calcite-fluorite separation. Background Art

[0002] Fluorite is the most important raw material for extracting fluorine. It is primarily used in the manufacture of glass, cement, fillers, and hydrofluoric acid, and as a flux in industrial steelmaking. Calcite is the primary gangue mineral in fluorite ore. Because both are calcium-containing minerals with similar surface properties, before using a collector for flotation separation of fluorite and calcite, a calcite inhibitor is added to inhibit the adsorption of the collector on the calcite surface without hindering its adsorption on the fluorite surface, thereby enabling the flotation of fluorite. Commonly used inhibitors include sodium silicate, citric acid, tannic acid, and starch. However, sodium silicate consumption is high and has a high heavy metal content. Organic inhibitors such as citric acid and tannic acid are expensive to produce, and these inhibitors make it difficult to effectively separate fluorite from calcium-containing gangue minerals such as calcite, resulting in substandard fluorite concentrate or low recovery rates. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for applying a fluorite flotation inhibitor in calcite-fluorite separation, aiming to solve the problems of difficulty in effectively separating fluorite and calcite, low grade of fluorite concentrate, and low recovery rate. The present invention innovatively uses sawdust pyrolysis liquid as an inhibitor for fluorite flotation. Unexpectedly, it is found that it can selectively inhibit calcite in fluorite ore while having almost no inhibitory effect on fluorite, thereby effectively separating fluorite from calcite, helping to improve the grade and recovery rate of fluorite concentrate and saving mineral processing costs. In addition, the application of sawdust pyrolysis liquid in the flotation of fluorite ore is expected to achieve its high-value utilization, and the use process does not require complex treatments such as purification and impurity removal, making it easy to use.

[0004] The method for applying the fluorite flotation depressant provided by the present invention in calcite-fluorite separation comprises the following steps:

[0005] S1. Preparation of fluorite flotation inhibitor: After grinding the sawdust, pyrolyzing it under a protective atmosphere, and condensing the gas in the pyrolysis product to obtain a pyrolysis solution, ie, the flotation inhibitor;

[0006] S2. Grinding the fluorite ore to obtain a slurry, and then sequentially adding a pH adjuster, the flotation depressant, and a collector for roughing to obtain a fluorite rough concentrate and fluorite roughing tailings;

[0007] S3. Add the flotation depressant to the fluorite coarse concentrate obtained in step S2 to perform concentrating to obtain a fluorite concentrate;

[0008] S4. Add a collector to the fluorite roughing tailings obtained in step S2, and perform scavenging to obtain fluorite tailings.

[0009] Preferably, in step S1, the wood chips are pine wood chips.

[0010] Preferably, in step S1, the particle size of the sawdust after grinding is less than 2 mm. If the particle size is too large, the pyrolysis reaction will take a long time.

[0011] Preferably, in step S1, the pyrolysis process parameters are: a pyrolysis temperature of 700-800°C and a holding time of 0.3-1.0h. If the pyrolysis temperature is too low, substances that inhibit fluorite production will be produced; if the pyrolysis temperature is too high, excessive energy consumption will result. If the holding time is too short, the pyrolysis liquid yield will be insufficient, while if the holding time is too long, it will also result in high energy consumption.

[0012] Preferably, in step S1, the protective atmosphere is nitrogen. If the oxygen content during the pyrolysis process is high, the yield of the pyrolysis solution will be reduced.

[0013] Preferably, in step S2, the particle size of the ground fluorite ore is -0.074 mm, accounting for 60% to 65%. Too fine or too coarse particle size of the ground fluorite ore will lead to fluorite loss.

[0014] Preferably, in step S2, the pH adjuster is dilute sulfuric acid, sodium carbonate or sodium hydroxide.

[0015] Preferably, in step S2, the pH adjuster is added to adjust the pH of the slurry to 7.0-9.0. The suitable pH range for flotation separation of fluorite and calcite is neutral to weakly alkaline. If the pH is too low, the floatability of fluorite is poor, affecting the fluorite recovery rate and increasing the amount of sulfuric acid used. If the pH is too high, the fluorite is inhibited.

[0016] Preferably, in step S2, the amount of the flotation depressant relative to the original ore is 1800-2000 g / t. In step S2, if the amount of the flotation depressant is too high, fluorite will be inhibited, while if the amount is too low, calcite will not be inhibited enough.

[0017] Preferably, in step S2, the collector is a fatty acid or fatty acid salt collector; the fatty acid salt collector is sodium oleate; and the amount of the collector relative to the original ore is 200-600 g / t.

[0018] In step S2, if the amount of collector is too high, it will make calcite difficult to suppress, and if the amount is too low, it will lead to a low fluorite recovery rate.

[0019] Preferably, in step S3, the amount of the flotation depressant relative to the original ore is 200-2000 g / t; the number of times of the concentrating is 3-7 times, and the time of each concentrating is 1-4 minutes.

[0020] Preferably, in step S4, the amount of the collector relative to the original ore is 200-2000 g / t; the number of sweeping is 2-3 times, and the time of each sweeping is 2-4 minutes.

[0021] The present invention has the following advantages and beneficial effects:

[0022] 1) The present invention uses sawdust as a raw material to prepare a fluorite flotation inhibitor, which not only has a low preparation cost but also effectively utilizes sawdust waste. In addition, the charcoal after pyrolysis can be used as a raw material for preparing activated carbon, and the preparation process can achieve zero emissions.

[0023] 2) Sawdust pyrolysis liquid is a mixture with complex components. Its application in other fields involves complex purification and impurity removal processes. However, the present invention uses it as a fluorite flotation inhibitor, which does not require purification and impurity removal, has a simple production process, and is conducive to industrial production.

[0024] 3) The sawdust pyrolysis liquid provided by the present invention mainly comprises phenolic and acidic substances such as catechol, 3,4-dihydroxytoluene, 4-ethylbenzene, 3-furfural, isobutyric acid, and 3,3-dimethylacrylic acid, as well as their pyrolysis small-molecule products. It has a strong selective inhibitory effect on calcite, but almost no inhibitory effect on fluorite, thereby improving the grade and recovery rate of fluorite concentrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flotation flow chart of the present invention.

[0026] Figure 2 This is the GC / MS total ion flow diagram of the liquid product (dissolved in n-hexane) pyrolyzed at 800℃.

[0027] Figure 3 This is the GC / MS total ion flow diagram of the liquid product (dissolved in ethyl acetate) pyrolyzed at 800°C.

[0028] Figure 4 This is a comparison chart of the main component contents of sawdust pyrolysis liquid at 500℃ and sawdust pyrolysis liquid at 800℃. DETAILED DESCRIPTION

[0029] The technical solutions of the present invention will be clearly and completely described below in the form of embodiments. It is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] Unless otherwise specified, the experimental methods used in the examples of the present invention are conventional methods. The materials and reagents used are commercially available unless otherwise specified. The g / t mentioned in the present invention refers to the mass of the reagent added per ton of raw ore.

[0031] Example 1

[0032] Preparation of flotation inhibitor: The sawdust was ground to less than 2 mm, and then pyrolyzed under nitrogen atmosphere at a pyrolysis temperature of 800 ° C for 0.5 h. The gas in the pyrolysis product was condensed and collected to obtain a pyrolysis liquid, i.e., the flotation inhibitor.

[0033] The components of the pyrolysis solution prepared in this example were detected and analyzed, and the results of the main components and their contents are shown in Tables 1 and 2, respectively.

[0034] Table 1 Main chemical components and mass fractions of the liquid products (n-hexane dissolved) pyrolyzed at 800℃

[0035]

[0036] Table 2 Main chemical components and mass fractions of the liquid products (dissolved in ethyl acetate) pyrolyzed at 800℃

[0037]

[0038] The prepared inhibitor was used to conduct a flotation test on a fluorite ore. The fluorite ore contained 29.81% fluorite (CaF2) and 38.71% calcite (CaCO3). Figure 1 The test steps are as follows:

[0039] (1) Grinding: Grind the fluorite ore in a ball mill to a grinding fineness of -0.074 mm, accounting for 60%, to obtain the flotation pulp;

[0040] (2) Roughing: The pulp was added to a flotation machine, and sulfuric acid was added to adjust the pH of the pulp to 8.0. After stirring for 3 minutes, 1800 g / t of the prepared flotation depressant was added and stirred for 3 minutes. Then, 500 g / t of sodium oleate was added and stirred for 3 minutes. Subsequently, flotation was carried out for 4 minutes to obtain fluorite roughing concentrate and fluorite roughing tailings.

[0041] (3) Concentration: The fluorite rougher concentrate was concentrated for 6 times. Before each concentration, the prepared flotation depressant was added and stirred for 2 minutes. The flotation time was 2 minutes. The dosage was 1000g / t, 600g / t, 400g / t, 300g / t, 200g / t, and 100g / t, respectively. The concentrated middlings were returned to the previous operation in order to finally obtain fluorite concentrate.

[0042] (4) Scavenging: The fluorite roughing tailings were scavenged twice, with the dosage of sodium oleate being 150 g / t and 60 g / t, respectively. The mixture was stirred for 2 min after addition, and the scavenging time was 2 min each time. Finally, fluorite tailings were obtained. The flotation results are shown in Table 3.

[0043] Example 2

[0044] Preparation of flotation inhibitor: The sawdust was ground to less than 2 mm, and then pyrolyzed under nitrogen atmosphere at a pyrolysis temperature of 700 ° C and a holding time of 0.5 h. The gas in the pyrolysis product was condensed and collected to obtain a pyrolysis liquid, i.e., the flotation inhibitor.

[0045] The prepared inhibitor was used to conduct a flotation test on a fluorite ore. The fluorite ore contained 29.81% fluorite (CaF2) and 38.71% calcite (CaCO3). Figure 1 The test steps are as follows:

[0046] (1) Grinding: Grind the fluorite ore in a ball mill to a grinding fineness of -0.074 mm, accounting for 60%, to obtain the flotation pulp;

[0047] (2) Roughing: The pulp was added to a flotation machine, and sulfuric acid was added to adjust the pH of the pulp to 8.0. After stirring for 3 minutes, 2000 g / t of the prepared flotation depressant was added and stirred for 3 minutes. Then, 500 g / t of sodium oleate was added and stirred for 3 minutes. Subsequently, flotation was carried out for 4 minutes to obtain fluorite roughing concentrate and fluorite roughing tailings.

[0048] (3) Concentration: The fluorite rougher concentrate was concentrating six times. Before each concentrating, the prepared flotation depressant was added and stirred for 2 minutes. The flotation time was 2 minutes. The dosages were 1400 g / t, 600 g / t, 500 g / t, 400 g / t, 200 g / t, and 100 g / t, respectively. The concentrating middlings were returned to the previous operation in order to finally obtain fluorite concentrate. The flotation results are shown in Table 3.

[0049] Comparative Example 1

[0050] This comparative example is a blank comparative example. Its flotation process is basically the same as that of Example 1, except that no inhibitor is added during the flotation process. The flotation results are shown in Table 3.

[0051] Comparative Example 2

[0052] Compared with Example 1, in this comparative example, the temperature of the wood chips pyrolysis was 400°C, and the pyrolysis liquid obtained at 400°C was used for flotation. Other conditions and the amount of reagents used remained unchanged. The flotation results are shown in Table 3.

[0053] Comparative Example 3

[0054] Compared with Example 1, in this comparative example, the temperature of the wood chips pyrolysis was 600°C, and the pyrolysis liquid obtained at 600°C was used for flotation, while other conditions and the amount of reagent remained the same. The flotation results are shown in Table 3.

[0055] Comparative Example 4

[0056] Compared with Example 1, in this comparative example, the temperature of the wood chips pyrolysis was 500°C, and the pyrolysis liquid obtained at 500°C was used for flotation. Other conditions and the amount of reagents used remained unchanged. The flotation results are shown in Table 3.

[0057] Comparative Example 5

[0058] Compared to Example 1, this comparative example used water glass as a depressant in the flotation process. The amount added in the roughing stage was 2500 g / t, and the depressant dosages in the six cleaning operations were 1200 g / t, 800 g / t, 400 g / t, 300 g / t, 200 g / t, and 100 g / t, respectively. Other conditions were the same. The flotation results are shown in Table 3.

[0059] Table 3 Flotation results using different flotation depressants

[0060]

[0061] Comparing Example 1 with Comparative Example 1, it can be seen that the grade of the fluorite concentrate in Example 1 increased by 48.3 percentage points. The pyrolysis solution has a significant inhibitory effect on calcite, significantly improving the grade of the fluorite concentrate. The test results of Comparative Examples 2 and 3 show that when the pyrolysis temperature is low, the pyrolysis solution has a certain inhibitory effect on fluorite. The results show that the pyrolysis solution produced at 800°C has a weak inhibitory effect on fluorite, but a stronger inhibitory effect on calcite. Compared with Comparative Example 5, the pyrolysis solution and method of use of the present invention can achieve flotation indicators similar to those of the widely used water glass, but the flotation reagent of the present invention is low in cost, allowing for high-value utilization of the pyrolysis solution.

Claims

1. A method for applying a fluorite flotation depressant in calcite-fluorite separation, comprising the following steps: S1. Preparation of fluorite flotation inhibitor: After grinding the sawdust, pyrolyzing it under a protective atmosphere, and condensing the gas in the pyrolysis product to obtain a pyrolysis solution, ie, the flotation inhibitor; S2. Grinding the fluorite ore to obtain a slurry, and then sequentially adding a pH adjuster, the flotation depressant, and a collector for roughing to obtain a fluorite rough concentrate and fluorite roughing tailings; S3. Add the flotation depressant to the fluorite coarse concentrate obtained in step S2 to perform concentrating to obtain a fluorite concentrate; S4. Adding a collector to the fluorite rougher tailings obtained in step S2, scavenging and selecting to obtain fluorite tailings; In step S1, the sawdust is pine sawdust; the particle size of the sawdust after grinding is less than 2 mm; the pyrolysis process conditions are: pyrolysis temperature is 700° C. to 800° C., holding time is 0.3 to 1.0 h; and the protective atmosphere is nitrogen.

2. The application method according to claim 1, characterized in that: In step S2, the particle size of the ground fluorite ore is -0.074 mm, accounting for 60% to 65%.

3. The application method according to claim 1, characterized in that: In step S2, the pH adjuster is dilute sulfuric acid, sodium carbonate or sodium hydroxide; the pH adjuster is added to adjust the pH of the slurry to 7.0-9.

0.

4. The application method according to claim 1, characterized in that: In step S2, the amount of the flotation depressant used relative to the original ore is 1800-2000 g / t.

5. The application method according to claim 1, characterized in that: In step S2, the collector is a fatty acid or fatty acid salt collector; the fatty acid salt collector is sodium oleate; and the amount of the collector relative to the original ore is 200-600 g / t.

6. The application method according to claim 1, characterized in that: In step S3, the amount of the flotation depressant relative to the original ore is 200-2000 g / t; the number of times of the flotation is 3-7 times, and the time of each flotation is 1-4 minutes.

7. The application method according to claim 1, characterized in that: In step S4, the amount of the collector relative to the original ore is 200-2000 g / t; the number of sweeping is 2-3 times, and the time of each sweeping is 2-4 minutes.

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