Influence of pulp ph on flotation of fluorite and calcite

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1 Advanced Materials Research Online: ISSN: , Vols , pp doi: / Trans Tech Publications, Switzerland Influence of pulp on flotation of fluorite and calcite Wenjuan Zhao 1,a, Dianwen Liu 1,b*, Hongshuai Li 1,c, Qicheng Feng 1,d, Guoyin Xu 1,e, Jingjie Yuan 1,f, Xiaodong Jia 1,g 1 Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming , Yunnan, China a wenjuan @163.com, b ldwkust@126.com (Corresponding Author), c @qq.com, d fqckmust@126.com, e @qq.com, f @qq.com, g @qq.com Key words: fluorite; calcite; flotation; zeta-potential; pulp ; infrared spectroscopy Abstract. Pulp value plays a significant role in the froth flotation. Especially in the flotation of fluorite, the performance of flotation will be affected greatly by pulp. MO, a new kind of modified fatty acid was used as collector, and H2SO4 and Na2CO3 were used to regulate pulp in the experiment. The mechanism of influence of pulp on flotation of fluorite and calcite was investigated by such parameters as fluorite recovery, zeta potentials and the infrared spectroscopy about minerals at different pulp values. As is shown in the results, the point of zero charge(pzc) of fluorite is =9.5 and the PZC of calcite is =8.5. The optimum pulp of the flotation of fluorite and calcite is determined as 9.5~10 and 8~9 respectively. value should be controlled above 9 to depress calcite. Finally, 9.5~10 was determined as the optimum to float the fluorite from the calcium-containing fluorite ores. Introduction Fluorite can be used in three major industries such as metallurgy, chemical industry and building materials, having an important relationship with the developing of the national economy. It mainly scatters in Asia, Africa, North America and Europe. With the increasing consumption of fluorite, high grade fluorite resources in the world are very few. At present, the fluorite ore mostly renders the characteristics with low grade, complex, associated ore. Now the fluorite ores in the world fall mostly into high silicon-calcium ones, intergrowing with quartz(sio 2 ), calcite(caco 3), schohartite and Sulfide ore. The major gangue minerals are quartz and calcite. Quartz is relatively easy to be separated from fluorite ore. But the calcite and fluorite(caf 2 ) are both the calcium-containing ores, being similar in nature, therefore, it s relatively more difficult to separate the two minerals. always plays an important role in the froth flotation [1-2], especially in the flotation of fluorite. Influence of on the flotation of fluorite and calcite was investigated in the work to discuss the mechanism of effect of on flotation of fluorite and calcite. Materials and Methods In order to investigate the mechanism of effect of on the flotation about fluorite, how the recovery and zeta-potential of fluorite and calcite change with the changing from 4 to 11 respectively was investigated. The tests were carried out in a 40ml flotation cell added with the sample of 2 grams. One rougher was adopted in the flotation experiments (Fig.2). The modified fatty acid collector (MO) was used as the collector and the was regulated by H 2 SO 4 and Na 2 CO 3. It will be mixed 2 min after dosing, and the scraping froth time should be controlled in 2 min. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-04/03/16,20:11:22)

2 Advanced Materials Research Vols The XRD patterns of the pure minerals (Fluorite and Calcite) are shown in Fig.1. Fig.1 XRD patterns of the pure minerals 1- Fluorite; 2- Calcite Fig.2 Flowsheet of the tests Results and discussion 3.1 Effect of value on fluorite flotation Effect of value on recovery of fluorite In order to investigate the influence of value on the recovery of fluorite, the experiment of flotation of fluorite was carried out under different values of 6~11. The experimental result is shown in Fig.3 Recovery(%) Fig.3 Effect of value on recovery of fluorite As is shown in Fig.3, the recovery of fluorite initially increases with the increasing of value. When the value increases to 8, the recovery of fluorite begins keeping stable. The recovery, however, of fluorite seriously decrease while the increases to 10. So it determines 8~10 as the optimum in the flotation of fluorite Effect of value on Zeta-potential of fluorite The 8~10 was determined as optimum in the flotation of fluorite from the results in Fig.3. In order to confirm the result, zeta-potential and infrared spectroscopy [3] of fluorite before and after collector adsorption under different values were investigated in the continuing tests. Results of zeta-potential and the infrared spectroscopy of fluorite are shown in Fig.4 and Fig.5, respectively.

3 616 Sustainable Development of Natural Resources Zeta potential/mv mg/L MO Deionized water Fig.4 Zeta-potential of fluorite in different media and value As is shown in Fig.5, the PZC of fluorite is =9.5. When the <9.5, the fluorite has a negatively charged surface. After collector adsorption, all the surface potential of fluorite negatively moves. Under the value of 9.5~10, the strongest negatively removing occurred to the surface potential of fluorite, which proves the optimum value of the flotation of fluorite should be controlled at 9.5~10. Fig.5 Infrared spectroscopy of fluorite before and after collector adsorption under different values. (1.pure mineral fluorite; 2. =7; 3. =6.5; =9.5) As is shown in Fig.5, after collector adsorption, the absorption peak of fluorite is changed. The absorption peak is changed slightly around =6.5, which shows that the adsorbance of collector increases slightly so that the surface characteristic of fluorite is not changed obviously. The absorption peak is greatly changed around =7 and =9.5, which shows that the adsorbance of collector increases obviously and the surface characteristic of fluorite is greatly changed. There is the largest adsorbance of collector at =9.5 which dues to an obvious shift of the absorption peak curve. To sum up, the result of infrared spectroscopy of fluorite is similar with that of the flotation of fluorite, giving a more accurate range, which determines the optimum value of the flotation of fluorite at 9.5~10.

4 Advanced Materials Research Vols Effect of value on calcite Effect of value on recovery of calcite 97 Recovery(%) Fig.6 Effect of value on recovery of calcite As is shown in Fig.6, recovery of calcite increases with the increasing of. When the value increases to 9, the recovery of calcite begins decreasing slowly. The recovery of calcite gets the top at =8~9. So the optimum value of the flotation of calcite is initially determined at 8~ Effect of value on Zeta-potential of calcite In order to verify the accuracy of the result of recovery of calcite, zeta-potential of calcite is investigated in the test. Result of the zeta-potential is shown in Fig.7. Zeta potential/mv mg/L MO Deionized water Fig.7 Zeta-potential of calcite in different media and value As is shown in Fig.7, the zeta-potential of calcite decreases with the increasing of. The PZC of calcite is =8.5. The entire surface potential of calcite negatively moves in the media of collector, which proves that the quantity of located ions(ca 2+ ) decreases with the adsorption of MO. The surface potential of calcite has the largest negatively changing around =8~9, which proves that there is the largest adsorbance of MO. Considering the results above, value should be controlled above 9 to depress calcite. Conclusions 1) According to the recovery of flotation of fluorite, a range from 8 to 10 was roughly determined as the optimum in the flotation of fluorite. 2) Results of zeta potentials and infrared spectroscopy of fluorite were similar with that of the flotation of fluorite, making a more accurate limits compared with that of recovery of fluorite. The optimum value of flotation of fluorite was limits at 9.5~10. 3) As the results of recoveries and zeta potentials, the PZC of fluorite and calcite is =9.5 and =8.5, respectively. The optimum value of the flotation of fluorite and calcite is determined at 9.5~10 and 8~9, respectively. value can be controlled above 9 to depress calcite 4) Finally, 9.5~10 was determined as the optimum to recover the fluorite from calcium-containing fluorite ores.

5 618 Sustainable Development of Natural Resources Acknowledgements This study was supported by the National Natural Science Foundation of China (Grant No ), Yunnan Provincial Young Science and Technology Reserve Talents Cultivation Fund Project(2011CZ012),the Joint Funds of the National Natural Science Foundation of China (Grant No. u ), and the Natural Science Foundation of Yunnan Province (Grant No. 2008ZC019M), also by the Doctoral Foundation Projects from the Ministry of Education of China(Grant No ). References [1] Y.Zhang, S.Song. Beneficiation of fluorite by flotation in a new chemical scheme.minerals Engineering, Vol. 13(2003), p [2] S.Song, A.Lopez-Valdivieso, C.Martinez-Martine, R.Torres-Armenta. Improving fluorite flotation from ores by dispersion processing. Minerals Engineering, Vol. 19(2006), p [3] J.S.HU, M.Misra, J.D.Miller. Characterization of adsorbed oleate species at the fluorite surface by FTIR spectroscopy. International Journal of Mineral Processing, Vol. 18(1986), p

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