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Combined use of high-efficiency flotation agent in black tungsten fine mud flotation
Gao Yude
Abstract: Starting from the action mechanism of black tungsten fine mud flotation agent, research on the separation of black tungsten fine mud and fluorite , calcite , quartz and other mineral flotation, and made a major breakthrough. In the slurry of pH 6.5-7.0, lead nitrate is used as the activator, water glass, aluminum sulfate and the like are combined inhibitors, and the combined collectors such as benzoic acid and tal soap are used as the donor grade WO. 3 1.62%, when the content of calcium mineral is more than 70%, and the order of -40μm is about 90%, the flotation process with WO 3 66.04% and recovery rate of 90.36% can be obtained by one selection, three selection and three sweeping processes. Concentrates, technical indicators have reached advanced levels, basically solved the technical problems of calcium-rich mineral black tungsten slurry recovery.
Key words: black tungsten fine mud; flotation; collector; inhibitor
China's tungsten resources and its rich, black tungsten ore reserves and mining scale ranks first in the world. Black tungsten ore is dense, brittle, and easy to pulverize. According to the National more than a dozen major black tungsten ore dressing plant to statistics, the coarse fraction of wolframite re-election method available good indicators fine grade wolframite recovery using gravity separation is limited granularity index is not high, The use of flotation rules may increase the recovery rate of black tungsten fines, the key is to use a reasonable process and effective flotation reagents.
Hunan Shizhuyuan wolframite ore metal Slimes, wolframite-containing (1.70%), fluorite (65.00%), calcite (10.00%), quartz (23.30%). Among them, the content of -40μm is about 90%, which belongs to calcium-containing refractory black tungsten fine mud, which is difficult to solve by re-election and general flotation process. In order to realize the separation of black tungsten ore and fluorite, calcite, quartz and other minerals, research on black tungsten fine mud flotation has been carried out, and a major breakthrough has been made, which basically solves the technical problem of black tungsten fine mud recovery in calcium-containing minerals.
1 collector and its mechanism of action
The flotation of black tungsten ore is a world problem, and it has not been well solved from the literature we have seen so far. Common collectors for black tungsten ore are fatty acids, sodium alkyl sulfate, A-22, phosphonic acid, citric acid, hydroxamic acid, and the like. In addition to the characteristics of ore, flotation process and other factors, the use of collectors is an important factor. Starting from the research of black tungsten ore collectors, a large number of exploration experiments were carried out on pure minerals. The benzene hydroxy hydroxy acid was used as the main collector.
1.1 Benzene hydroxamic acid collector
The benzoxamic acid used is a pale yellow scaly crystal which can react with various metal ions to form a stable chelate compound. Benzohydroxamic acid is an effective collector for wolframite, fluorite and calcite, with a maximum recovery of 99% for all three minerals. In the flotation system with benzyl hydroxamic acid as a collector, the wolframite has a wide flotation range, and its pH value is 4.0 to 10.5. However, in the range of different pH, benzoic acid is used for the wolframite, There is a certain difference in the collection of fluorite and calcite. When pH < 5.8, fluorite and calcite are poorly floatable, while wolframite still maintains high recovery in acidic media. It can be considered that the flotation separation of scheelite and fluorite and calcite can be carried out in the range of pH<5.8. However, due to the presence of calcite in the slurry, they can react with calcite to form carbon dioxide, whether it is adjusted with sulfuric acid or hydrochloric acid. Water and new salt. To reduce the pH of the slurry to below 5.8, a large amount of acid will be consumed, which will increase the cost of the agent and cause corrosion of the equipment, which is difficult to achieve in actual production. When the pH value is 7.5 ~ 10.0, benzoxamic acid has the same degree of harvesting ability for the three minerals. To achieve the separation of the wolframite from fluorite and calcite, effective inhibitors must be added. When pH>10.0, the floatability of the wolframite, fluorite and calcite decreased significantly.
1.2 Mechanism of action of benzyl hydroxamic acid on wolframite
Benzohydroxamic acid is a typical chelating agent. It has two tautomers, which form a chelating ligand in solution. The coordinating atoms are oxygen and nitrogen atoms, which can form strong bonds with metal ions. Used in combination to form a relatively stable chelate.
The metal ions in the black tungsten ore crystal lattice are Fe 2+ , Mn 2+ and WO 4 2- . During the crushing and grinding process, the ore is cleavage or fractured by the external force along the weakest bond of the mineral crystal structure. Fine particles of uneven and irregular surfaces. Since the particles and the specific surface area can increase the surface area, and generating an unsaturated bond is not compensated in breaks, in an aqueous solution, the surface is first positioned Tungsten ions and free OH - Hydroxy hydration generates Mn (OH) n (n is generally 4). Benzohydroxamic acid is bound to Fe 2+ and Mn 2+ on the surface of the wolframite by N and O atoms to form a chelate. The main mechanism of action is surface chemical reaction adsorption [1] . The non-polar group of benzyl hydroxamic acid is a benzene ring group, which is a short-chain compound, which is the main reason why the agent is easily soluble in water, low in hydrophobicity, and unstable in foam [2] .
1.3 Complementary and synergistic effects between collectors
The key of mineral flotation is to improve the selective adsorption of the collector on the surface of the target mineral. The single use of benzoxamic acid as the black tungsten ore collector has poor selectivity, large dosage and unstable flotation foam. To improve the collector effect, reducing the amount of benzyl hydroxamic acid, in addition to using effective inhibitors outer flotation, by selecting a test tal oil soap with coal as an auxiliary collector, shared with benzohydroxamic acid The performance complementarity and synergistic effect between the medicaments are fully exerted, the effect of the collector is enhanced, and the amount of benzoic acid is greatly reduced. When the ore grade is WO 3 1.63%, the pH is 6.5-7.0, the activator lead nitrate 300g/t, the combined inhibitor 600g/t, and the benzoic acid-based combination collector 500g/t enters. By rough selection, coarse concentrate with grade WO 3 8.76% and recovery rate of 79.03% was obtained, and the selectivity of black tungsten fine mud flotation was significantly improved [3] .
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2 inhibitors and their mechanism of action
Effective collectors must work with the appropriate effective inhibitors to make a greater difference. When the pH is 6.5-7.0, lead nitrate is used as the activator, and three pure minerals such as wolframite, fluorite and calcite are floated separately with benzoxamic acid. The test results show that the recovery rate of the wolframite is up to 99. %, but to achieve the separation of the black tungsten ore from fluorite and calcite, the corresponding inhibitor must be added. This shows that the inhibitor also plays an important role in the flotation of black tungsten fine mud, lacking effective inhibitors, and the black tungsten fine mud cannot be separated from minerals such as fluorite and calcite.
2.1 Water glass inhibition mechanism
As we all know, water glass is an inorganic colloid, which is a commonly used inhibitor in flotation operations. It has inhibitory effects on quartz, silicate minerals and calcite, and is also a dispersing agent for slime.
Water glass inhibition mechanism [4] :
(1) H 2 SiO 3 , HSiO 3 - , and SiO 3 2- in water glass are adsorbed on the surface of the mineral to suppress the hydrophilicity of the slurry. Since the adsorption capacity of various minerals adsorbing H 2 SiO 3 , HSiO 3 - , and SiO 3 2- and the degree of adsorption firmness are different, a variety of minerals can be sorted by using water glass.
(2) The negatively charged colloidal SiO 2 adsorbs on the surface of minerals such as positively charged calcite and acts as a suppressor. The adsorbed on the surface of the slime makes the mineral particles negatively charged, and the negative electricity mutually repels the role of dispersing the slime.
2.2 Water glass combined with high-priced weakly alkaline metal ions
Single use of water glass as an inhibitor, the selection of inhibition effect is poor. In order to improve the suppression effect of water glass selection, carboxymethyl cellulose, aluminum sulfate and water glass were used in the test to exert synergistic effects between the agents, and the inhibitory effect of inhibitor selection was enhanced. The inhibition mechanism of carboxymethyl cellulose is due to the interaction of hydroxyl groups introduced by etherification on each glucose unit in the molecule with Ca 2+ , and the two hydroxyl groups adsorbed on the surface of these minerals are hydrophilic and inhibit. . Therefore, carboxymethyl cellulose can inhibit minerals such as calcite and fluorite. The use of water glass in combination with aluminum sulfate improves the selective inhibition performance. Al 3+ is a high-priced weakly basic metal ion. The inhibition mechanism shared with water glass is that water glass is hydrolyzed in the slurry to form OH - , OH - and high-valent metal ions to form weak alkaline hydroxide, thus promoting water glass. Hydrolysis produces more colloidal silicates, which are also colloidal materials that are intermixed with water glass colloids to increase the selectivity of inhibition. In the black-tungsten fine mud flotation test of Shizhuyuan Mine, aluminum sulfate and water glass were used together, and obvious inhibition effect was obtained.
3 black tungsten fine mud flotation test results
The black tungsten fine mud flotation process is a rough selection, three sweeps, three selections, and the middle mine returns in sequence. The pH of the slurry was adjusted by 6.5 to 7.0 with sulfuric acid, and the dosage of each agent was shown in Table 1. The rough selection operation mainly uses a combination of water-glass-based inhibitor AD, activator lead nitrate and benzoic acid-based combined collector BH; the third stage of the selected operation uses modified Na 2 SiF 6 The inhibitor and flotation concentrate grades have been greatly improved. The results of the closed circuit test are shown in Table 2. The test results show that the combined inhibitor AD and modified Na 2 SiF 6 are effective inhibitors for the separation of fine-grained hematite and flotation of calcium-containing minerals; the combination collector BH based on benzoic acid is black. Efficient selective collector for tungsten fines flotation.
Table 1 dosage of each working agent / (g·t -1 )
operation
H 2 SO 4
AD
Pb(NO 3 ) 2
BH
Na 2 SiF 6
Rough selection
Featured one
Featured 2
Featured three
Sweep one
Sweeping two
Sweep three
1500
250
800
300
100
400
500
115
115
190
90
90
60
Table 2 Closed-circuit process test results /%
product name
Yield
WO 3 grade
Recovery rate
Flotation concentrate
Flotation tailings
Give mine
2.22
97.78
100.0
66.04
0.16
1.62
90.36
9.64
100.0
4 industrial test and production indicators
Industrial test and production indicators for 1999 are shown in Table 3. Due to changes in on-site production process conditions, the ore properties of black tungsten fine mud flotation ore are completely different from those of small test ore samples, resulting in a large difference between industrial test and production indicators and small test indicators, but compared with traditional recycling methods. A major breakthrough was made, which basically solved the technical problems of black tungsten fine mud recovery at home and abroad.
Table 3 Industrial test and production indicators /%
Project
product name
Yield
WO 3 grade
Recovery rate
Industrial test
Industrial production
Flotation concentrate
Feed mine
Flotation concentrate
Feed mine
2.49
6.38
52.74
1.93
48.91
4.40
68.07
70.89
5 conclusions
(1) The combined inhibitors AD and Na 2 SiF 6 which are common to water glass, aluminum sulfate and the like are effective inhibitors of black tungsten fine mud flotation which is rich in calcium minerals.
(2) Using a combination of common reagents such as benzoxamic acid and tal soap, the performance complementarity and synergistic effect between the agents are exerted, which not only enhances the effect of the collector, but also greatly reduces the benzoquinone. Acid dosage.
(3) The combined use of high-efficiency flotation agent in black tungsten fine mud flotation basically solves the technical problem of black tungsten fine mud flotation at home and abroad. When the ore grade contains WO 3 1.63% and the calcium mineral content is more than 70%, the unfavorable test results of WO 3 66.04% and recovery rate of 90.36% are obtained. Technical indicators have reached the international advanced level.
references
1 Wang Dianzuo. Principle and application of flotation agent. Beijing: Metallurgical Industry Press, 1992, 54
2 Zeng Weidong, Ye Zhiping. Proceedings of the 3rd Academic Conference of China Nonferrous Metals Society. 1997, 65
3 Gao Yude et al. Journal of Nonferrous Metals of Guangdong, 1994, 4(1)20
4 Zhu Yushuang, Zhu Jianguang. Black tungsten and cassiterite fine mud flotation agent. Changsha: Zhongnan Institute of Mining and Metallurgy, 1981, 160