A combined collector and its application in scheelite flotation

Abstract

The present application belongs to the field of calcium-containing mineral flotation, and particularly relates to a combined collector, which comprises a collector A and a collector B, wherein the collector A is at least one compound with the structural formula of formula 1; the collector B is a collector capable of collecting scheelite; in R1-R4, at least two substituents are substituents of formula a, and the remaining substituents are H, C1-C3 alkyl or formula a. The present application also includes the use of the combined collector for the collection and flotation of scheelite. The combined collector can synergistically improve the flotation of scheelite and help to improve the selective flotation separation of scheelite and calcium-containing gangue.

Description

Technical Field

[0001] This invention relates to the field of mineral flotation technology, specifically to a combined collector and method for the flotation separation of scheelite and other calcium-containing minerals. Background Technology

[0002] Tungsten, with the chemical symbol W and atomic number 74, is an important rare metal. It possesses excellent physicochemical properties such as a high melting point, high density, wear resistance, and corrosion resistance. Many countries classify it as a strategic metal, and it is widely used in high-end instruments, molds, and military applications, holding a significant strategic position. The main source of tungsten metal is scheelite. my country's industrially applicable tungsten resources are scheelite and wolframite, with scheelite (CaWO4) accounting for approximately two-thirds of tungsten reserves. It has a hardness of 4.5 and is mostly light yellow in color.

[0003] Scheelite (CaWO4) is a major source of tungsten metal. However, scheelite is primarily intergrowthed with other calcium-bearing minerals, making the separation of scheelite from other calcium-bearing gangue minerals a key focus of scheelite beneficiation. Although my country has abundant scheelite resources, their grade is low, and they are often closely associated with calcium-bearing minerals such as fluorite (CaF2) and calcite (CaCO3), exhibiting fine particle size and making separation difficult. Flotation (also known as froth flotation) is the primary method for processing this type of mineral resource. However, since their active sites are all Ca atoms, the adsorption selectivity of flotation reagents is poor, and traditional flotation theory has limitations. This makes the flotation separation of calcium-bearing minerals a recognized global challenge in the mineral processing field.

[0004] Currently, in low temperatures during winter, the activity of commonly used collectors such as sodium oleate and its modified collectors is greatly reduced, and industrial processes typically increase their dosage to maintain beneficiation plant parameters. This not only leads to the excessive use of collectors, increasing reagent costs, but also directly raises the cost of subsequent tailings treatment. Meanwhile, the industrial method for separating scheelite and other calcium-bearing minerals, especially fluorite, is primarily the high-alkali method. This involves adding lime, NaOH, and water glass to adjust the pulp pH to above 12, suppressing calcium-bearing minerals such as calcite and fluorite, and preferentially flotating scheelite. This high-alkali method has the following drawbacks: the addition of a large amount of water glass in a highly alkaline environment strongly inhibits fluorite, making subsequent fluorite recovery very difficult, with most of the fluorite being lost. Furthermore, when using tungsten tailings for fluorite beneficiation, the activation of some gangue minerals makes it difficult to improve the grade of the fluorite concentrate. Based on current processes, significant losses of fluorite or scheelite are inevitable. Furthermore, the addition of large amounts of water glass slows down the settling of tailings, which is detrimental to tailings treatment and wastewater reuse.

[0005] Therefore, in order to achieve green and efficient separation of scheelite and other calcium-bearing minerals, there is an urgent need to find a combined collector and method for the flotation separation of scheelite and other calcium-bearing minerals. Summary of the Invention

[0006] The primary objective of this invention is to provide a combined collector capable of synergistically improving the flotation performance of scheelite.

[0007] The second objective of this invention is to provide an application method for using the aforementioned combined collector to collect scheelite and separate it from other calcium-bearing gangue by flotation.

[0008] To address the global challenge of separating scheelite from other calcium-bearing gangue minerals during flotation, this invention provides the following improvement:

[0009] A combined collector comprising collector A and collector B, wherein collector A is at least one compound having a structural formula of Formula 1; and collector B is a collector capable of collecting scheelite.

[0010]

[0011] Of R1 to R4, at least two substituents are substituents of formula a, and the remaining substituents are H, C1 to C3 alkyl groups, or formula a;

[0012]

[0013] The x and y values ​​are C1 to C1 respectively. 12 Alkylene; wherein M is H, Na, K or NH4.

[0014] This invention innovatively discovers that collector A alone has virtually no collecting ability for scheelite. However, when combined with collector B, it can unexpectedly achieve synergy, significantly improving the collecting ability for scheelite. In addition, it can also improve the flotation separation selectivity of scheelite and other calcium-bearing gangue.

[0015] In this invention, the intramolecular synergy of the structure of Formula 1 is the key to improving its synergy with collector B and thus improving the scheelite collection performance.

[0016] Preferably, 3 to 4 of the substituents in R1 to R4 are substituents of formula a;

[0017] In this invention, C1 to C 12The alkylene group can be a straight-chain or branched alkylene group having 1 to 12 carbon atoms. For example, the C1 alkylene group can be methylene. The C2 alkylene group can be 1,2-ethylene. The C3 alkylene group can be 1,3-propylene. The C4 alkylene group can be 1,4-butylene. The C5 alkylene group can be 1,5-pentylene. The C6 alkylene group can be 1,6-hexylene. The C7 alkylene group can be 1,7-heptylene. The C8 alkylene group can be 1,8-octylene. The C9 alkylene group can be 1,9-nonylene. 10 The alkylene group can be 1,10-decene. C 11 The alkylene group can be 1,11-undecylene. C 12 The alkylene group can be 1,12-dodecylene.

[0018] As a specific scheme, x is C2 to C 12 The alkylene group can be further defined as x being a C4 to C8 alkylene group.

[0019] As a specific embodiment, y represents methylene or ethylene.

[0020] Further preferably, the collector A comprises formula 1-A;

[0021]

[0022] In Equation 1-A, x is C2 to C 12 The alkylene group can be further classified as a C4 to C8 alkylene group.

[0023] In this invention, the collector B can be any collector known in the industry that can be used for scheelite flotation, such as a fatty acid collector, and more specifically, a collector of fatty acids with a carbonic acid content of 10-20 and their sodium or potassium salts. In a typical embodiment of this invention, the fatty acid collector is at least one of oleic acid and its salts, or oxidized paraffin soap.

[0024] The ratio of collector A and collector B in the combined collector of the present invention can be adjusted according to the flotation requirements. For example, as a typical embodiment, the mass ratio of collector A to collector B is 0.5:1 to 3:1. Considering the processing cost and effect, it can be further 1 to 2:1.

[0025] The present invention also provides the application of the aforementioned combined collector, using it as a collector for the flotation of scheelite.

[0026] This invention has found that the combined use of collectors A and B can synergistically improve the collection capacity of scheelite, thus helping to achieve better positive flotation of scheelite.

[0027] In a more preferred embodiment of the present invention, the combined collector is used as a collector for selectively collecting scheelite from a mixture of scheelite and other calcium-bearing minerals.

[0028] This invention has found that, thanks to the combined synergistic effect of A and B in the combined collector, not only can the collection and flotation of scheelite be improved, but also the flotation separation selectivity of scheelite and its associated, especially intercalated, calcium-bearing gangue can be improved.

[0029] In this invention, the calcium-containing mineral is at least one of fluorite and calcite.

[0030] In this invention, the dosage of the combined collector in the flotation stage can be adjusted as needed. Considering the effect and benefits, it is preferably 50-200 g / t.

[0031] In this invention, the pH of the pulp during the flotation stage is 9–12; preferably 9.5–11.5, and more preferably 10–11. Studies have found that at the preferred pH, the effectiveness of the combined collector can be further improved, and the separation selectivity of scheelite and calcium-bearing gangue can be further improved.

[0032] In this invention, the temperature during the flotation stage is less than 100°C, preferably 5–40°C. Thanks to the innovative use of the combined collector, this invention allows the flotation process to be adapted to different operating conditions, especially in low-temperature flotation conditions, where it achieves better results than existing processes.

[0033] In this invention, the flotation machine rotation speed in the flotation process is 1600-2000 r / min, preferably 1650-1750 r / min.

[0034] The application of the technical solution of the present invention has the following beneficial effects:

[0035] (1) The present invention shows that combining the collectors A and B can achieve synergy and can be used as collectors to effectively achieve flotation of scheelite, and can also achieve highly selective flotation separation of scheelite and calcium-containing gangue; it improves the grade and recovery rate of scheelite rough concentrate and solves the problem of excessive gangue minerals in scheelite caused by the use of existing flotation processes for low-grade scheelite.

[0036] (2) The present invention can still exhibit excellent selective collection ability of scheelite in low temperature environment, which greatly improves the flotation effect in low temperature environment.

[0037] (3) The collector described in this invention has the advantages of readily available raw materials, low cost and no secondary pollution; in addition, the collector is used in small quantities, has strong selectivity and high stability in practical applications, and has great potential for promotion and market application prospects.

[0038] (4) The flotation method described in this invention has simple steps, easy-to-control parameters, and the flotation process is carried out in a mild environment. It does not require the addition of a large amount of acid or alkali, which effectively saves costs and avoids environmental pollution problems. In addition, this invention uses a combination collector to float out the scheelite rough concentrate in the slurry. It does not require the use of a high-alkali method or the addition of a large amount of water glass and other inhibitors to suppress other gangue minerals, thus avoiding the complex separation process used to separate other gangue minerals in the subsequent scheelite beneficiation operation. Detailed Implementation

[0039] The following examples are intended to further illustrate the content of this invention, but are not intended to limit the scope of protection of the claims of this invention.

[0040] This invention provides a combined collector, specifically a combined collector for scheelite flotation. It comprises collector A of formula 1 and conventional collector B suitable for scheelite flotation.

[0041] In this invention, the collector A preferably contains two, and more preferably four or more, substituent fragments of formula a, so that it can be combined intramolecularly based on structure, thereby improving its synergistic effect with the collector B.

[0042] The collector A may further include formula 1-A.

[0043] The collector B can be a fatty acid collector commonly used in the industry.

[0044] This invention, through research, has discovered that the innovative use of a combination of collectors A and B as a collector for scheelite unexpectedly and significantly improves the separation selectivity of scheelite with other calcium-bearing minerals, resulting in high-grade scheelite and effectively improving scheelite recovery. Furthermore, this method can greatly enhance the recovery rate of scheelite using fatty acid collectors at low temperatures, while significantly inhibiting other calcium-bearing minerals without the need for inhibitors, demonstrating superior selectivity.

[0045] In this invention, the other calcium-containing minerals are at least one of fluorite and calcite.

[0046] In this invention, the fatty acid collector is oxidized paraffin soap, sodium oleate, etc.

[0047] The present invention unexpectedly discovered that the combined use of collectors A and B can synergistically improve the separation selectivity between scheelite and other calcium-bearing minerals, thereby improving the grade and recovery rate of scheelite concentrate.

[0048] In this invention, the mass ratio of collectors A and B is 0.5:1 to 3:1; more preferably 0.8:1 to 2:1.

[0049] In this invention, based on existing methods, the combined collector described in this invention can be used to collect scheelite and achieve selective flotation separation of scheelite and other calcium-bearing gangue.

[0050] For example, the flotation step is as follows: scheelite is mixed with another calcium-containing mineral to obtain a mixed ore, which is then crushed and prepared into a pulp. The flotation reagent is then added to the pulp for flotation. In this invention, the pulp can be obtained using existing grinding and pulping methods, and the flotation reagent can be added at any stage of the grinding, pulping, or pulping process.

[0051] During the flotation process, the particle size and content of the pulp are 60-90% of that of -0.074mm.

[0052] The dosage of the combined collector can be 50-200 g / t.

[0053] During the flotation process, a pH adjuster can be used to regulate the pH of the pulp. In one specific embodiment of the present invention, the pulp pH is controlled at 9–12 during the flotation stage; more further, it can be 9.5–11.5, and even more further, it can be 10–11. The acid used in the pH adjustment process can be at least one of hydrochloric acid, nitric acid, and sulfuric acid, and the base can be sodium hydroxide or sodium carbonate, etc.

[0054] In this invention, the temperature of the slurry in the flotation stage is greater than 0 and less than 100°C; preferably 5 to 40°C.

[0055] Example 1

[0056] This case study uses a combination of collectors for the flotation of pure scheelite and calcite minerals;

[0057] The mixed collector includes collector 1 and collector 2, with a mass ratio of 1.5:1. Collector 1 and collector 2 are mixed evenly in advance according to the mass ratio of 1.5:1.

[0058] Collector 1:

[0059] Collector 2: Oxidized paraffin soap

[0060] The flotation of scheelite or calcite involved the following steps: 2g of scheelite or calcite with a particle size of -74 to +38μm and 40mL of deionized water were added to a flotation cell. After stirring at 1700 rpm for 1 minute, the aforementioned mixed collector (64mg / L) was added. Stirring continued for 3 minutes, and the pulp pH was adjusted to 10.0. Stirring continued for another 2 minutes for aerated flotation, followed by 3 minutes of flotation at 10℃. Finally, the concentrate and tailings were dried and weighed separately. The calculated recoveries of scheelite and calcite were 93.42% and 5.17%, respectively, with a separation index of 88.25% (the absolute value of the difference in recovery between scheelite and calcite). This result indicates that the mixed collector has better selectivity for scheelite.

[0061] Example 2

[0062] This case study uses a collector for the flotation of pure scheelite and fluorite minerals;

[0063] The mixed collector comprises collector 1 and collector 2 in a mass ratio of 1:1. Collector 1 and collector 2 are mixed evenly in advance according to the mass ratio of 1:1.

[0064] Collector 1:

[0065] Collector 2: Sodium oleate

[0066] The flotation process for scheelite or fluorite involves the following steps: 2g of scheelite or fluorite with a particle size of -74 to +38μm and 40mL of deionized water are added to a flotation cell. After stirring at 1700 rpm for 1 minute, the aforementioned mixed collector (58mg / L) is added. Stirring continues for 3 minutes, and the pulp pH is adjusted to 10.0. Stirring continues for another 2 minutes for aerated flotation, followed by 3 minutes of flotation at 10℃. Finally, the concentrate and tailings are dried and weighed separately. The calculated recoveries for scheelite and fluorite are 93.72% and 3.66%, respectively, with a separation index of 90.10%. This result indicates that the combined collector exhibits better selectivity for scheelite.

[0067] Example 3

[0068] The flotation of a mixed ore of scheelite and fluorite involved the following steps: 2g of a mixed ore with a particle size of -74 to +38μm (mass ratio 1:1) and 40mL of deionized water were added to a flotation cell. After stirring at 1700r / min for 1min, the mixed collector described in Example 2 was added at a concentration of 58mg / L. Stirring continued for 3min, and the pulp pH was adjusted to 10.0. Stirring continued for 2min for aerated flotation, followed by 3min at 10℃. Finally, the concentrate and tailings were dried, weighed, and tested for WO3 grade. The calculated WO3 grade and recovery rate in the scheelite concentrate were 75.03% and 91.27%, respectively. This result indicates that the combined collector exhibits better selectivity for scheelite.

[0069] Example 4

[0070] This case study uses a combination of collectors for the flotation of actual scheelite ore.

[0071] The mixed collector comprises collector 1 and collector 2 in a mass ratio of 1.5:1. Collector 1 and collector 2 are mixed evenly in advance according to the mass ratio of 1.5:1.

[0072] Collector 1:

[0073] Collector 2: Oxidized paraffin soap

[0074] The scheelite was selected from a location in Hunan Province, with a WO3 grade of 0.36% and a CaF2 grade of 8.32%. The actual scheelite was ground to a fineness of -0.074 mm, with 70% of the dry ore being dry and the pulp concentration controlled at 50%. Then, 100 g / t of mixed collector was added, and after stirring for 3 minutes, the pH was adjusted to 10.5 with sodium carbonate. Stirring continued for 2 minutes, followed by aeration. Roughing flotation tests were conducted at 10℃, yielding a tungsten concentrate with a WO3 grade of 1.42% and a recovery rate of 67.51%, but with a CaF2 grade of 3.31% and a recovery rate of only 6.71%.

[0075] Example 5

[0076] This case study uses a combination of collectors for the flotation of actual scheelite ore.

[0077] The mixed collector comprises collector 1 and collector 2, with a mass ratio of 2:1.

[0078] Collector 1:

[0079] Collector 2: Sodium oleate

[0080] The scheelite was selected from a location in Jiangxi Province, with a WO3 grade of 0.33% and a CaCO3 grade of 18.71%. The actual scheelite was ground to a fineness of -0.074 mm, with 73% of the dry ore content being dry ore and the pulp concentration controlled at 45%. Then, 80 g / t of mixed collector was added, and after stirring for 3 minutes, the pH was adjusted to 10 with sodium carbonate. Stirring continued for 2 minutes, followed by aeration. Roughing flotation tests were conducted at 10℃, yielding a tungsten concentrate with a WO3 grade of 1.14% and a recovery rate of 76.28%, but with a CaCO3 grade of only 11.77% and a recovery rate of only 13.91%.

[0081] Comparative Example 1

[0082] Except for replacing the mixed collector with a single oxidized paraffin soap (in the same amount as the total amount of collector in Example 1), everything else was the same as in Example 1. The recoveries of the obtained scheelite and calcite were 53.74% and 89.47%, respectively, with a separation index of 35.73%.

[0083] Comparative Example 2

[0084] Compared with Example 1, the only difference is that collector 2 is omitted, and the amount of the remaining collector 1 is the same as the total amount of collector in Example 1. Other operations and parameters are the same as in Example 1.

[0085] The recoveries of scheelite and calcite were 15.47% and 32.75%, respectively, with a separation index of 17.28%. Collector 1 alone was practically incapable of demonstrating collecting ability.

[0086] Comparative Example 3

[0087] Except that the mixed collector was replaced with a single oxidized paraffin soap (in the same amount as the total amount of collector in Example 1), and the flotation environment was 25°C, everything else was the same as in Example 1. The recoveries of the obtained scheelite and calcite were 88.16% and 45.22%, respectively, with a separation index of 42.94%.

[0088] Example 6

[0089] Except for the flotation environment being 25°C, which differed from Example 1, everything else was consistent with Example 1. The recoveries of the obtained scheelite and calcite were 92.94% and 8.83%, respectively, with a separation index of 84.11%.

[0090] Comparison of the results of Comparative Examples 1-3 with those of Examples 1 and 6 shows that the combined collector can promote the collection of fatty acid collectors on scheelite under both low and normal temperature conditions, and has a good separation effect.

[0091] Example 7

[0092] Except for the flotation pH, which differs from Example 2, all other aspects are consistent with Example 2. The flotation recoveries of scheelite and fluorite at different pH values ​​are shown in Table 1.

[0093] Table 1. Flotation recoveries of scheelite and fluorite at different pH values

[0094] pH Scheelite recovery rate / % Fluorite recovery rate / % 9 47.37 33.65 11 93.21 3.87 12 84.59 3.15

[0095] Comparing the results in Table 1 and Example 7, it can be seen that the mixed collector has a collecting ability for scheelite over a wide pH range, but the optimal separation pH for scheelite and fluorite is 9 to 12; more preferably 10 to 11.

[0096] Comparative Example 4

[0097]

[0098] Except for replacing Formula 2-a in Example 3 with the reagent of the comparative Formula a structure described above, everything else was the same as in Example 3. After flotation with the comparative mixed collector, the WO3 grade and recovery rate were 36.78% and 57.49%, respectively. Compared with the results of Example 3, without using the main collector structure described in this invention, it is impossible to synergistically improve the selective separation of scheelite from other calcium-bearing minerals with the auxiliary collector.

[0099] Comparative Example 5

[0100] Except for replacing the combined collector with a single oxidized paraffin soap collector and adjusting the flotation temperature to 25°C room temperature, everything else was the same as in Example 4. In the obtained tungsten rough concentrate, the WO3 grade and recovery were 0.77% and 65.50%, respectively, and the CaF2 grade and recovery were 14.54% and 46.61%, respectively. Compared to the results in Example 4, without the combined collector described in this invention, scheelite and fluorite could not be separated effectively.

[0101] Example 8

[0102] Except for adjusting the flotation temperature to 25°C (room temperature), everything else was the same as in Example 4. In the obtained tungsten rough concentrate, the WO3 grade and recovery were 1.40% and 66.84%, respectively, and the CaF2 grade and recovery were 3.77% and 8.15%, respectively. Compared to the results in Example 4, temperature did not affect the flotation-promoting effect or separation effect of this combination of collectors on scheelite.

[0103] Comparative Example 6

[0104] Except for replacing the combined collector with a single sodium oleate collector and adjusting the flotation temperature to 25°C room temperature, everything else was the same as in Example 5 (e.g., the total collector dosage in the flotation stage remained unchanged). In the obtained tungsten rough concentrate, the WO3 grade and recovery were 0.62% and 68.55%, respectively, and the CaCO3 grade and recovery were 31.31% and 59.96%, respectively. Compared to the results in Example 5, without the combined collector described in this invention, scheelite and calcite could not be separated effectively.

[0105] Comparative Example 7

[0106] Except for replacing the combined collector with a single sodium oleate collector, everything else was the same as in Example 5 (e.g., the total collector dosage in the flotation stage remained unchanged). In the obtained tungsten rough concentrate, the WO3 grade and recovery were 1.12% and 43.30%, respectively, and the CaCO3 grade and recovery were 21.04% and 13.91%, respectively. Compared to the results in Example 5, sodium oleate exhibited poor collecting properties at lower temperatures; without the combined collector described in this invention, scheelite and calcite could not be effectively separated.

[0107] Therefore, considering the flotation separation effect, the combined collector in this invention can significantly improve the selective collection of scheelite, and can achieve the separation of scheelite from gangue minerals such as fluorite and calcite in a green and efficient manner.

[0108] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A combined collector for collecting scheelite, characterized in that, It is composed of collector A and collector B, wherein collector A includes formula 1-A; Formula 1-A In Formula 1-A, x is a C4-C8 alkylene group; Collector B is a fatty acid with 10-20 carbon atoms and its sodium or potassium salt; The mass ratio of collector A to collector B is 1~2:

1.

2. The combined collector as described in claim 1, characterized in that, The collector B is at least one of oleic acid and its salts, or oxidized paraffin soap.

3. The application of the combined collector according to any one of claims 1 to 2, characterized in that, It is used as a collector in the flotation of scheelite.

4. The application of the combined collector as described in claim 3, characterized in that, It is used as a collector for the selective collection of scheelite from minerals containing scheelite and other calcium-bearing minerals.

5. The application of the combined collector as described in claim 4, characterized in that, The calcium-containing mineral is at least one of fluorite and calcite.

6. The application of the combined collector as described in claim 3, characterized in that, During the flotation stage, the dosage of the combined collector is 50~200 g / t.

7. The application of the combined collector as described in any one of claims 3 to 6, characterized in that, The pH of the pulp during the flotation stage is 9-12.

8. The application of the combined collector as described in claim 7, characterized in that, The pH of the pulp during the flotation stage is 10-11.

9. The application of the combined collector as described in any one of claims 3 to 6, characterized in that, The temperature during the flotation stage is 5~40℃.

10. The application of the combined collector as described in claim 9, characterized in that, The flotation machine speed in the flotation process is 1600-2000 r / min.

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