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The influence of composition of nonpolar oil on flotation of molybdenite
Minerals Engineering 24 (2011) 1513–1516
Contents lists available at ScienceDirect
Minerals Engineering journal homepage: www.elsevier.com/locate/mineng
Technical Note
The influence of composition of nonpolar oil on flotation of molybdenite Tingshu He a, He Wan a,⇑, Nianping Song b, Lin Guo b a b
School of Materials Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China China Molybdenum Co., Ltd., Luanchuan 471500, China
a r t i c l e
i n f o
Article history: Received 19 February 2011 Accepted 4 July 2011 Available online 28 July 2011 Keywords: Sulphide ores Flotation collectors Mineral processing
a b s t r a c t With increasing molybdenum ore mining, the difficult to treat ores, i.e., lower-grade and fine-disseminated ores have gradually increased in importance. Kerosene was widely used as the conventional collector of molybdenum flotation all along, but it does not adapt well to the flotation of molybdenite in difficult to treat ores. Meanwhile, kerosene has been cancelled from the manufacture catalogue in China, which makes large refineries no longer produce it, and in turn makes it difficult for a molybdenum flotation plant to purchase kerosene and makes it even harder for kerosene to keep a stable composition. Therefore, many molybdenum flotation plants began to apply diesel oil instead of kerosene as collector for molybdenite. However, the flotation results reveal that diesel oil from different manufacturers or being of different specifications from the same manufacturers has a different effect on the flotation of molybdenite, and pulp temperature has an obvious effect on the flotation efficiency of diesel oil. In pulp temperatures ranging from 10 to 30 °C, the flotation recovery of molybdenite increases with increasing high-boiling component in diesel oil. When pulp temperature is below 10 °C, the flotation recovery of molybdenite is related to the dispersibility of diesel oil, i.e., the proportion of high-boiling and low-boiling component in diesel oil. Therefore, a molybdenum flotation plant should not blindly apply diesel oil instead of kerosene as the collector for molybdenite, but should select diesel oil that is suitable for the properties of its ore. This technical note is helpful to better select the proper collector for a molybdenum flotation plant. Ó 2011 Elsevier Ltd. All rights reserved.
1. Introduction Molybdenite possesses excellent natural floatability (Chander and Fuerstenau, 1972; Kelebek, 1988; Zanin et al., 2009). Nonpolar hydrocarbon oil is the most applicable collector for it, such as kerosene, diesel oil, transformer oil and solar oil. Kerosene, as a conventional collector for molybdenite, has been widely used in molybdenum flotation. However, due to the fact that increasingly molybdenum ores are mined, the difficult ores, i.e., lower-grade and fine-disseminated ores have gradually increased. Meanwhile, as market demand for kerosene is declining, it has been cancelled from the manufacture catalogue in China, which makes large refineries not produce kerosene any more. At present, kerosene is hard to purchase, and it is increasingly difficult to ensure its stable composition, which leads to a harmful effect on the molybdenum production. Kerosene has some disadvantages as collector for molybdenite. Firstly, the addition amount for kerosene is 25% more than for diesel oil in the flotation process and the content of kerosene is higher than that of diesel oil in molybdenum concentrate. A large of kerosene will adsorb on molybdenum concentrate sur⇑ Corresponding author. Tel./fax: +86 29 82201271. E-mail address: [email protected] (H. Wan). 0892-6875/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.mineng.2011.07.003
faces. It is easy for the molybdenum concentrate to agglomerate during the roasting, which will reduce the efficiency of roasting. In addition, it is difficult to dewater (Cumming et al., 2000) and the further processing has strict requirements on the content of oil, water, and other impurities in the molybdenum concentrate (Ye et al., 2009; Muratore and Voevodin, 2006). Secondly, the price of kerosene is 15% higher than that of diesel oil. Finally, kerosene has a weak collecting ability for the intergrowth particles of mineral and gangue. It is difficult to obtain high recovery for processing lower-grade and fine-disseminated ores. Diesel oil has higher collecting ability than kerosene and can be easily purchased and is less expensive, so many molybdenum flotation plants began to apply diesel oil instead of kerosene as the collector for molybdenite. Many studies (Crozier, 1979; Smit and Bhasin, 1985; Xia and Peng, 2007; Wang et al., 2008; Song et al., 1999) have shown the collecting ability of hydrocarbon oil enhances as its carbon chain length increases, which contributes to the enhancement of collecting ability for coarse molybdenite and intergrowths of molybdenite with gangue. However, too long a carbon chain would bring down the dispersibility of hydrocarbon oil in pulp, causing the adverse effect of recovery decline of the valuable mineral. In order to provide a perfect substitute for kerosene, the author, in this paper, studies the influence of different kinds of diesel oil from different
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T. He et al. / Minerals Engineering 24 (2011) 1513–1516
manufacturers on the flotation of molybdenite and the influence of pulp temperature on the dispersibility of diesel oil. 2. Materials and methods 2.1. Materials and reagents The molybdenite sample used in this study was from the tungsten–molybdenum mine of Luanchuan in Henan Province, China. It is a skarn type tungsten molybdenum deposit, in which molybdenite occurs as a major phase and scheelite as a minor phase. Typically, Mo concentration ranges from 0.04% to 0.3%. These mineral samples were crushed to below 2 mm and removed to a porcelain ball mill. Then, the fraction (0.147–0.043 mm) was obtained by screening as flotation samples. The chemical analysis of the mineral sample is given in Table 1. The reagents used in this study were: diesel oil as the collector for molybdenite, diesel oil from various sources (see Table 2), pine camphor oil as the frother from China Molybdenum Co., Ltd., and sodium silicate as the dispersant/depressant of silicate minerals/ pH modifier from China Molybdenum Co., Ltd. Tap water was used in the whole experiment. 2.2. Experimental procedure Flotation was conducted in a 3L hitch groove flotation machine at a rotating speed of 1700/min. In the flotation process, a 1 kg mineral sample was added into a flotation cell for further processing. The sequence of reagent addition was regulator, collector and frother. The conditioning times for regulator, collector and frother were 2 min, 2 min and 1 min, respectively. The flotation time was 7 min. The flotation tests were undertaken at the normal pulp temperature of 20 °C and the low pulp temperature of 5 °C. 2.3. Data processing methods In order to inspect the repeatability from replicate tests, each test condition was repeated five times. Five test results gave an arithmetic average value, and the analysis of variance was used to confirm the reliability of test results. The most reliable and reasonable data will be used for making summary graphs and analyzing test results. 3. Results and discussion Six kinds of diesel oil from different manufacturers were selected to serve as the collectors of flotation, numbering from diesel oil 1 to diesel oil 6. The influences of the dosage of each kind of diesel oil at pulp temperatures of 20 °C and 5 °C respectively are shown in Figs. 1 and 2. As shown in Fig. 1, for the tests at normal pulp temperature of 20 °C, the molybdenum recovery increases with increasing the dosage of diesel oil, but the recovery curve becomes flat after the dosage is greater than 160 g/t. This indicates the optimum dosage of diesel oil as collector for the molybdenite sample is 160 g/t in this study, the molybdenum recovery from diesel oil 1 to diesel oil 6 as collector being close to 93.00%/93.00%/92.00%/90.50%/ 91.00%/89.50%. The ranking of collectors based on the recovery
from high to low is diesel oil 1, diesel oil 2, diesel oil 3, diesel oil 5, diesel oil 4 and diesel oil 6. The flotation recoveries of diesel oil 1 and 2 are nearly the same and significantly better than that of the other diesel oils at normal temperature of 20 °C. Diesel oil 1, diesel oil 3 and diesel oil 5 are of the same specification, but from different manufacturers, and their recoveries are 92.77%, 91.89% and 90.93%, respectively, which can indicate that diesel oil from different manufacturers has a different effect on the molybdenum flotation even if being the same specification. Diesel oil 3 and 4 and diesel oil 5 and 6 are of different specifications, but from the same manufacturer (Table 2), and their recoveries are 91.89%, 90.39% and 90.93%, 89.13%, respectively, which can indicate that diesel oil of different specifications has a different effect on the molybdenum flotation even if being from the same manufacturer. Thus, Fig. 1 shows that diesel oil from different manufacturers or being of different specifications from the same manufacturer has a different effect on molybdenum flotation. As shown in Fig. 2, for the tests at the pulp temperature of 5 °C, the molybdenum recovery increases with increasing the dosage of diesel oil, and the recovery curves of any diesel oil have a lower but clear gradient after the dosage is greater than 160 g/t, which is not the same as the tests at the pulp temperature of 20 °C. When the dosages of diesel oil are equal to the optimum dosages of 160 g/t at 5 °C, the molybdenum recoveries from diesel oil 1 to diesel oil 6 as collector are 90.5%/92.32%/90.67%/89.95%/90.41%/88.54%. The ranking of collectors based on the recovery from high to low is diesel oil 2, diesel oil 3, diesel oil 1, diesel oil 5, diesel oil 4 and diesel oil 6, being different from that at 20 °C. The recovery of diesel oil 2 is significantly better than that of the other diesel oils at a low pulp temperature. Compared with the tests at pulp temperature of 20 °C, the recoveries of diesel oil decrease at 5 °C, i.e., the recoveries of diesel oil 1/diesel oil 2/diesel oil 3/diesel oil 4/diesel oil 5/diesel oil 6 at 20 °C and 5 °C are 92.77%/92.61%/91.89%/ 90.39%/90.93%/89.13% and 90.50%/92.32%/90.67%/89.95%/90.41%/ 88.54%, respectively. This indicates the decrease of pulp temperature has a negative effect on the flotation of molybdenite when diesel oil was used as the collector for molybdenite. As everyone knows, nonpolar oil is generally used for the molybdenum collector, whose chain length and dispersibility are the major factors contributing to its collecting ability. The maximum length of the carbon chain is closely related to the boiling point of diesel oil. The higher the boiling point of diesel oil, the longer the maximum length of carbon chain is. When pulp temperature is above 10 °C, the dispersibility of diesel oil is excellent, the carbon chain length takes the leading role, the collecting ability of hydrocarbon oil increases with the increase of its carbon chain length, which contributes to the enhancement of collecting ability for coarse molybdenite and intergrowths of molybdenite with gangue. When pulp temperature is below 10 °C, the high-boiling component in diesel has a poor dispersibility in pulp. If the diesel oil has more high-boiling component, it is difficult to disperse in low temperature pulp, causing an adverse effect on the recovery of desired mineral particles. Adjusting the percentage of high-boiling component and the maximum length of carbon chain in diesel oil can contribute to change the dispersibility so as to eliminate the adverse influence of pulp temperature. It can be verified that crude oil components or production processes of diesel oil are different all over China, causing the diesel oil
Table 1 The chemical analysis of mineral sample. Chemical compositions
Mo
WO3
Cu
Pb
Zn
S
Al2O3
SiO2
MgO
Na2O
K2O
TFe
Wt (%)
0.12
0.07
0.007
0.005
0.016
1.81
7.89
48.50
2.86
1.08
0.82
10.12
The TFe means total content of Fe in metallic and non-metallic minerals.
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T. He et al. / Minerals Engineering 24 (2011) 1513–1516 Table 2 Diesel oil sources. Name in experiment
Manufacturer
Specification (#)
Diesel Diesel Diesel Diesel Diesel Diesel
Shanxi Yanchang Petroleum (Group) Co. Ltd. Shanxi Yanchang Petroleum (Group) Co. Ltd. China National Petroleum Corporation Lanzhou Company China National Petroleum Corporation Lanzhou Company China Petroleum and Chemical Corporation Luoyang Company China Petroleum and Chemical Corporation Luoyang Company
0
oil oil oil oil oil oil
1 2 3 4 5 6
10 0 10 0 10
Fig. 1. The influence of diesel oil from different manufacturers on flotation of molybdenite in normal pulp temperature: temperature range from 10 to 30 °C, temperature of flotation test being 20 °C.
Fig. 2. The influence of diesel oil from different manufacturers on flotation of molybdenite in low pulp temperature: temperature range from 0 to 10 °C, temperature of flotation test being 5 °C.
from different manufacturers or being of different specification from the same manufacturer, to have different composition and
average carbon chain length, and in turn to have a different effect on the flotation of molybdenite. Therefore, a molybdenum flotation
1516
T. He et al. / Minerals Engineering 24 (2011) 1513–1516
plant should not blindly apply diesel oil instead of kerosene as collector for molybdenite, but should select the diesel oil suitable for the properties of its ore, which has the optimum high-boiling component in diesel oil and proper average carbon chain length. In the paper, diesel oil 2 is the most applicable collector for molybdenite of Luanchuan. 4. Conclusions Diesel oil from different manufacturers or being of different specification from the same manufacturer has a different effect on flotation of molybdenite. The decrease of pulp temperature can reduce the dispersibility of diesel oil, especially the high-point component in diesel oil. Low pulp temperature has a negative effect on the molybdenum flotation when diesel oil is used as collector. Therefore, a molybdenum flotation plant should not blindly apply diesel oil instead of kerosene as collector for molybdenite, but should select diesel oil suitable for the properties of its ore. In this technical note, diesel oil 2 is the most applicable collector for molybdenite of Luanchuan. Acknowledgments This work was supported by China Molybdenum Co., Ltd., and Xi’an University of Architecture and Technology.
References Chander, S., Fuerstenau, D.W., 1972. On the natural flotability of molybdenite. Trans. Am. Inst. Min. Metall. Eng. 252, 62–69. Crozier, R.D., 1979. Flotation reagent practice in primary and by-product molybdenite recovery. Min. Mag. 140, 174–178. Cumming, I.W., Holdich, R.G., Smith, I.D., 2000. The rejection of oil by microfiltration of a stabilised kerosene/water emulsion. J. Membr. Sci. 169, 147–155. Kelebek, S., 1988. Critical surface tension of wetting and of flotability of molybdenite and sulphur. J. Colloid Interface Sci. 124, 504–514. Muratore, C., Voevodin, A.A., 2006. Molybdenum disulfide as a lubricant and catalyst in adaptive nanocomposite coatings. Surf. Coat. Technol. 201, 4125– 4130. Smit, F.J., Bhasin, A.K., 1985. Relationship of petroleum hydrocarbon characteristics and molybdenite flotation. Int. J. Miner. Process 15, 19–40. Song, S.X., Lopez-Valdivieso, A., Ding, Y.Q., 1999. Effects of nonpolar oil on hydrophobic flocculation of hematite and rhodochrosite fines. Powder Technol. 101, 73–80. Wang, H., Gu, G.H., Fu, J.G., Hao, Y., 2008. Study of the interfacial interactions in the molybdenite floatation system. J. China Univ. Min. Technol. 18, 82–87. Xia, Y.K., Peng, F.F., 2007. Selection of frothers from residual organic reagents for copper–molybdenite sulfide flotation. Int. J. Miner. Process. 83, 68–75. Ye, Y.P., Chen, J.M., Zhou, H.D., 2009. An investigation of friction and wear performances of bonded molybdenum disulfide solid film lubricants in fretting conditions. Wear 266, 859–864. Zanin, M., Ametov, I., Grano, S., Zhou, L., Skinner, W., 2009. A study of mechanisms affecting molybdenite recovery in a bulk copper/molybdenum flotation circuit. Int. J. Miner. Process. 93, 256–266.
Contents lists available at ScienceDirect
Minerals Engineering journal homepage: www.elsevier.com/locate/mineng
Technical Note
The influence of composition of nonpolar oil on flotation of molybdenite Tingshu He a, He Wan a,⇑, Nianping Song b, Lin Guo b a b
School of Materials Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China China Molybdenum Co., Ltd., Luanchuan 471500, China
a r t i c l e
i n f o
Article history: Received 19 February 2011 Accepted 4 July 2011 Available online 28 July 2011 Keywords: Sulphide ores Flotation collectors Mineral processing
a b s t r a c t With increasing molybdenum ore mining, the difficult to treat ores, i.e., lower-grade and fine-disseminated ores have gradually increased in importance. Kerosene was widely used as the conventional collector of molybdenum flotation all along, but it does not adapt well to the flotation of molybdenite in difficult to treat ores. Meanwhile, kerosene has been cancelled from the manufacture catalogue in China, which makes large refineries no longer produce it, and in turn makes it difficult for a molybdenum flotation plant to purchase kerosene and makes it even harder for kerosene to keep a stable composition. Therefore, many molybdenum flotation plants began to apply diesel oil instead of kerosene as collector for molybdenite. However, the flotation results reveal that diesel oil from different manufacturers or being of different specifications from the same manufacturers has a different effect on the flotation of molybdenite, and pulp temperature has an obvious effect on the flotation efficiency of diesel oil. In pulp temperatures ranging from 10 to 30 °C, the flotation recovery of molybdenite increases with increasing high-boiling component in diesel oil. When pulp temperature is below 10 °C, the flotation recovery of molybdenite is related to the dispersibility of diesel oil, i.e., the proportion of high-boiling and low-boiling component in diesel oil. Therefore, a molybdenum flotation plant should not blindly apply diesel oil instead of kerosene as the collector for molybdenite, but should select diesel oil that is suitable for the properties of its ore. This technical note is helpful to better select the proper collector for a molybdenum flotation plant. Ó 2011 Elsevier Ltd. All rights reserved.
1. Introduction Molybdenite possesses excellent natural floatability (Chander and Fuerstenau, 1972; Kelebek, 1988; Zanin et al., 2009). Nonpolar hydrocarbon oil is the most applicable collector for it, such as kerosene, diesel oil, transformer oil and solar oil. Kerosene, as a conventional collector for molybdenite, has been widely used in molybdenum flotation. However, due to the fact that increasingly molybdenum ores are mined, the difficult ores, i.e., lower-grade and fine-disseminated ores have gradually increased. Meanwhile, as market demand for kerosene is declining, it has been cancelled from the manufacture catalogue in China, which makes large refineries not produce kerosene any more. At present, kerosene is hard to purchase, and it is increasingly difficult to ensure its stable composition, which leads to a harmful effect on the molybdenum production. Kerosene has some disadvantages as collector for molybdenite. Firstly, the addition amount for kerosene is 25% more than for diesel oil in the flotation process and the content of kerosene is higher than that of diesel oil in molybdenum concentrate. A large of kerosene will adsorb on molybdenum concentrate sur⇑ Corresponding author. Tel./fax: +86 29 82201271. E-mail address: [email protected] (H. Wan). 0892-6875/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.mineng.2011.07.003
faces. It is easy for the molybdenum concentrate to agglomerate during the roasting, which will reduce the efficiency of roasting. In addition, it is difficult to dewater (Cumming et al., 2000) and the further processing has strict requirements on the content of oil, water, and other impurities in the molybdenum concentrate (Ye et al., 2009; Muratore and Voevodin, 2006). Secondly, the price of kerosene is 15% higher than that of diesel oil. Finally, kerosene has a weak collecting ability for the intergrowth particles of mineral and gangue. It is difficult to obtain high recovery for processing lower-grade and fine-disseminated ores. Diesel oil has higher collecting ability than kerosene and can be easily purchased and is less expensive, so many molybdenum flotation plants began to apply diesel oil instead of kerosene as the collector for molybdenite. Many studies (Crozier, 1979; Smit and Bhasin, 1985; Xia and Peng, 2007; Wang et al., 2008; Song et al., 1999) have shown the collecting ability of hydrocarbon oil enhances as its carbon chain length increases, which contributes to the enhancement of collecting ability for coarse molybdenite and intergrowths of molybdenite with gangue. However, too long a carbon chain would bring down the dispersibility of hydrocarbon oil in pulp, causing the adverse effect of recovery decline of the valuable mineral. In order to provide a perfect substitute for kerosene, the author, in this paper, studies the influence of different kinds of diesel oil from different
1514
T. He et al. / Minerals Engineering 24 (2011) 1513–1516
manufacturers on the flotation of molybdenite and the influence of pulp temperature on the dispersibility of diesel oil. 2. Materials and methods 2.1. Materials and reagents The molybdenite sample used in this study was from the tungsten–molybdenum mine of Luanchuan in Henan Province, China. It is a skarn type tungsten molybdenum deposit, in which molybdenite occurs as a major phase and scheelite as a minor phase. Typically, Mo concentration ranges from 0.04% to 0.3%. These mineral samples were crushed to below 2 mm and removed to a porcelain ball mill. Then, the fraction (0.147–0.043 mm) was obtained by screening as flotation samples. The chemical analysis of the mineral sample is given in Table 1. The reagents used in this study were: diesel oil as the collector for molybdenite, diesel oil from various sources (see Table 2), pine camphor oil as the frother from China Molybdenum Co., Ltd., and sodium silicate as the dispersant/depressant of silicate minerals/ pH modifier from China Molybdenum Co., Ltd. Tap water was used in the whole experiment. 2.2. Experimental procedure Flotation was conducted in a 3L hitch groove flotation machine at a rotating speed of 1700/min. In the flotation process, a 1 kg mineral sample was added into a flotation cell for further processing. The sequence of reagent addition was regulator, collector and frother. The conditioning times for regulator, collector and frother were 2 min, 2 min and 1 min, respectively. The flotation time was 7 min. The flotation tests were undertaken at the normal pulp temperature of 20 °C and the low pulp temperature of 5 °C. 2.3. Data processing methods In order to inspect the repeatability from replicate tests, each test condition was repeated five times. Five test results gave an arithmetic average value, and the analysis of variance was used to confirm the reliability of test results. The most reliable and reasonable data will be used for making summary graphs and analyzing test results. 3. Results and discussion Six kinds of diesel oil from different manufacturers were selected to serve as the collectors of flotation, numbering from diesel oil 1 to diesel oil 6. The influences of the dosage of each kind of diesel oil at pulp temperatures of 20 °C and 5 °C respectively are shown in Figs. 1 and 2. As shown in Fig. 1, for the tests at normal pulp temperature of 20 °C, the molybdenum recovery increases with increasing the dosage of diesel oil, but the recovery curve becomes flat after the dosage is greater than 160 g/t. This indicates the optimum dosage of diesel oil as collector for the molybdenite sample is 160 g/t in this study, the molybdenum recovery from diesel oil 1 to diesel oil 6 as collector being close to 93.00%/93.00%/92.00%/90.50%/ 91.00%/89.50%. The ranking of collectors based on the recovery
from high to low is diesel oil 1, diesel oil 2, diesel oil 3, diesel oil 5, diesel oil 4 and diesel oil 6. The flotation recoveries of diesel oil 1 and 2 are nearly the same and significantly better than that of the other diesel oils at normal temperature of 20 °C. Diesel oil 1, diesel oil 3 and diesel oil 5 are of the same specification, but from different manufacturers, and their recoveries are 92.77%, 91.89% and 90.93%, respectively, which can indicate that diesel oil from different manufacturers has a different effect on the molybdenum flotation even if being the same specification. Diesel oil 3 and 4 and diesel oil 5 and 6 are of different specifications, but from the same manufacturer (Table 2), and their recoveries are 91.89%, 90.39% and 90.93%, 89.13%, respectively, which can indicate that diesel oil of different specifications has a different effect on the molybdenum flotation even if being from the same manufacturer. Thus, Fig. 1 shows that diesel oil from different manufacturers or being of different specifications from the same manufacturer has a different effect on molybdenum flotation. As shown in Fig. 2, for the tests at the pulp temperature of 5 °C, the molybdenum recovery increases with increasing the dosage of diesel oil, and the recovery curves of any diesel oil have a lower but clear gradient after the dosage is greater than 160 g/t, which is not the same as the tests at the pulp temperature of 20 °C. When the dosages of diesel oil are equal to the optimum dosages of 160 g/t at 5 °C, the molybdenum recoveries from diesel oil 1 to diesel oil 6 as collector are 90.5%/92.32%/90.67%/89.95%/90.41%/88.54%. The ranking of collectors based on the recovery from high to low is diesel oil 2, diesel oil 3, diesel oil 1, diesel oil 5, diesel oil 4 and diesel oil 6, being different from that at 20 °C. The recovery of diesel oil 2 is significantly better than that of the other diesel oils at a low pulp temperature. Compared with the tests at pulp temperature of 20 °C, the recoveries of diesel oil decrease at 5 °C, i.e., the recoveries of diesel oil 1/diesel oil 2/diesel oil 3/diesel oil 4/diesel oil 5/diesel oil 6 at 20 °C and 5 °C are 92.77%/92.61%/91.89%/ 90.39%/90.93%/89.13% and 90.50%/92.32%/90.67%/89.95%/90.41%/ 88.54%, respectively. This indicates the decrease of pulp temperature has a negative effect on the flotation of molybdenite when diesel oil was used as the collector for molybdenite. As everyone knows, nonpolar oil is generally used for the molybdenum collector, whose chain length and dispersibility are the major factors contributing to its collecting ability. The maximum length of the carbon chain is closely related to the boiling point of diesel oil. The higher the boiling point of diesel oil, the longer the maximum length of carbon chain is. When pulp temperature is above 10 °C, the dispersibility of diesel oil is excellent, the carbon chain length takes the leading role, the collecting ability of hydrocarbon oil increases with the increase of its carbon chain length, which contributes to the enhancement of collecting ability for coarse molybdenite and intergrowths of molybdenite with gangue. When pulp temperature is below 10 °C, the high-boiling component in diesel has a poor dispersibility in pulp. If the diesel oil has more high-boiling component, it is difficult to disperse in low temperature pulp, causing an adverse effect on the recovery of desired mineral particles. Adjusting the percentage of high-boiling component and the maximum length of carbon chain in diesel oil can contribute to change the dispersibility so as to eliminate the adverse influence of pulp temperature. It can be verified that crude oil components or production processes of diesel oil are different all over China, causing the diesel oil
Table 1 The chemical analysis of mineral sample. Chemical compositions
Mo
WO3
Cu
Pb
Zn
S
Al2O3
SiO2
MgO
Na2O
K2O
TFe
Wt (%)
0.12
0.07
0.007
0.005
0.016
1.81
7.89
48.50
2.86
1.08
0.82
10.12
The TFe means total content of Fe in metallic and non-metallic minerals.
1515
T. He et al. / Minerals Engineering 24 (2011) 1513–1516 Table 2 Diesel oil sources. Name in experiment
Manufacturer
Specification (#)
Diesel Diesel Diesel Diesel Diesel Diesel
Shanxi Yanchang Petroleum (Group) Co. Ltd. Shanxi Yanchang Petroleum (Group) Co. Ltd. China National Petroleum Corporation Lanzhou Company China National Petroleum Corporation Lanzhou Company China Petroleum and Chemical Corporation Luoyang Company China Petroleum and Chemical Corporation Luoyang Company
0
oil oil oil oil oil oil
1 2 3 4 5 6
10 0 10 0 10
Fig. 1. The influence of diesel oil from different manufacturers on flotation of molybdenite in normal pulp temperature: temperature range from 10 to 30 °C, temperature of flotation test being 20 °C.
Fig. 2. The influence of diesel oil from different manufacturers on flotation of molybdenite in low pulp temperature: temperature range from 0 to 10 °C, temperature of flotation test being 5 °C.
from different manufacturers or being of different specification from the same manufacturer, to have different composition and
average carbon chain length, and in turn to have a different effect on the flotation of molybdenite. Therefore, a molybdenum flotation
1516
T. He et al. / Minerals Engineering 24 (2011) 1513–1516
plant should not blindly apply diesel oil instead of kerosene as collector for molybdenite, but should select the diesel oil suitable for the properties of its ore, which has the optimum high-boiling component in diesel oil and proper average carbon chain length. In the paper, diesel oil 2 is the most applicable collector for molybdenite of Luanchuan. 4. Conclusions Diesel oil from different manufacturers or being of different specification from the same manufacturer has a different effect on flotation of molybdenite. The decrease of pulp temperature can reduce the dispersibility of diesel oil, especially the high-point component in diesel oil. Low pulp temperature has a negative effect on the molybdenum flotation when diesel oil is used as collector. Therefore, a molybdenum flotation plant should not blindly apply diesel oil instead of kerosene as collector for molybdenite, but should select diesel oil suitable for the properties of its ore. In this technical note, diesel oil 2 is the most applicable collector for molybdenite of Luanchuan. Acknowledgments This work was supported by China Molybdenum Co., Ltd., and Xi’an University of Architecture and Technology.
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