石墨选矿及晶体保护试验研究
摘要
我国石墨资源丰富,储量和产销量均居世界首位,而鳞片石墨由于具有独特的物理化学性能,已在冶金、电气、化工等工业部门中获得广泛应用。一方面’,大鳞片石墨(一般指+0.3mm、+0.18mm)经济价值比细粒级高,而制造坩埚及膨胀石墨等用途必须使用大鳞片石墨,细粒级的不能使用,现代的工业技术也无法生产大鳞片石墨,一旦被破坏就无法恢复。另一方面,我国大鳞片石墨储量低,在选别过程中由于复杂的再磨流程致使石墨鳞片破坏严重,产量较少,导致市场供不应求。因此,探索石墨浮选中如何保护石墨晶体不被破坏,合理选择再磨工艺,提高大鳞片产率及精矿质量,对充分发挥我国石墨资源优势具有重大的经济意义。
对鞍山岫岩石墨矿进行工艺矿物学的研究表明,该矿属于鳞片状石墨矿,固定碳含量为10.47%,主要呈鳞片状、片状单体或集合体,脉石矿物为透闪石、石英、云母、长石等。对该石墨的嵌布特征分析结果表明,该石墨矿中含有20%～30%的+0.15mm粒级的大颗粒,选矿中应注意保护大鳞片,提高石墨产品价值。
首先对该石墨矿进行粗选药剂条件试验,再以最佳药剂条件下浮选所得粗精矿为原料,研究不同再磨设备、再磨介质以及介质不同配比对保护石墨晶体的影响,结果表明,振动磨及柱介质对石墨晶体保护效果最佳。在最佳的再磨工艺条件下,进行粗精矿再磨细度、开路试验、中矿返回方式试验以及闭路试验,最终获得石墨精矿固定碳96.34%,回收率94.11%,+0.15mm级别产率16.17%(固定碳含量95.43%),尾矿固定碳0.69%的优良选别指标。
浮选机理分析表明,煤油主要以物理吸附方式吸附在石墨表面,在磨机中加入碳酸钠作为调整剂,既可以分散矿泥,还可以作为助磨剂提高磨矿效果。磨矿动力学理论研究表明,磨矿时磨矿介质的冲击力,容易使石墨鳞片发生垂直于结晶层面的断裂,此时,大鳞片石墨遭受破坏的几率大,而沿鳞片石墨结晶层面施加的碾磨或剥磨力,则容易使石墨鳞片沿结晶层面解离,此时大鳞片遭受破坏的几率小。因此选择磨剥及碾磨作用的振动磨,能更好地适应磷片石墨的层状结晶特性,既能大幅度地提高精矿品位,又能较好的保护大鳞片。
China is very rich in graphite, with reserves and production and sales volume ranking first in the world. Because of the unique physical and chemical properties, flake graphite has been widely available in the metallurgical, electrical, chemical and other industrial field. On the one hand, big flake graphite (usually+0.3 mm,+0.18 mm) has higher economic value than the fine grade,and some fields such as crucible and expanded graphite manufacturing must use big flake graphite, fine-grained level can not be used. We can not produce big flake graphite under modern industrial technology, once destroyed it can not be restored. On the other hand,big flake graphite in China is of low-scale,and the graphite flake is ususlly severely damaged due to the complex re-grinding process, leading to low yield and short market supply. Therefore, studying how to protect the graphite crystal during graphite flotation not to be destroyed and exploring reasonable re-grinding process to improve the big flake yield and the quality of concentrate has great economic significance on the full resources of graphite.
Process mineralogy studies on Graphite Mine in Anshan Xiuyan showed that the mine belonged to flake graphite ore, with fixed carbon content of 10.47%, mainly existing as scaly, single flaky or aggregates.The main gangue minerals are tremolite, quartz, mica, feldspar and so on. The results of disseminated characteristics of the graphite showed that the graphite mine contained 20%-30% of the+0.15 mm big particles.We should protect the big flake during mineral processing and improve the value of graphite products.
Firstly, research on pharmacy conditions of rough selection was carried out Then the effects of different re-grinding equipment, grinding media and different proportions of the media on the protection of graphite crystals were studied,with the crude concentrate as raw material which was obtained from crude flotation under the the best agents conditions.The results showed that the vibration mill and column media could provide The best protection effect on the crysta.Finally,on the base of the best re-grinding process conditions, the tests of the rough concentrate re-grinding degree, open trial, the way back of middlings mine and closed-circuit process were all carried out.Ultimately, high quality concentrate was obtained with concentrate fixed carbon content of 96.34%, recovery rate of 94.11%,+0.15 mm level yield of 16.17% (fixed carbon content of 95.43%), tailings fixed carbon of 0.69%.
Flotation mechanism showed that kerosene mainly adsorbed on graphite surface by physical adsorption, and adding sodium carbonate as a modifier in the mill can not only spread the sludge but also be used as aids to improve the grinding effect. Grinding kinetic theory studies showed that the impact force from grinding media may occur perpendicular fracture to the crystalline graphite flake,then would lead to more probability of big flake graphite destruction.The pan and peeling force along flake graphite crystalline level can make the flake graphite segregate easily along the dissociation level,then would decrease the probability of big flake damage.Therefore, vibration mill with the role of vibration and peeling was chosen as re-grinding equipment,which can better adapted to the layered crystalline characteristics of flake graphite.It can not only greatly improve the concentrate grade, but also provide better protection for big flake graphite.
对鞍山岫岩石墨矿进行工艺矿物学的研究表明,该矿属于鳞片状石墨矿,固定碳含量为10.47%,主要呈鳞片状、片状单体或集合体,脉石矿物为透闪石、石英、云母、长石等。对该石墨的嵌布特征分析结果表明,该石墨矿中含有20%～30%的+0.15mm粒级的大颗粒,选矿中应注意保护大鳞片,提高石墨产品价值。
首先对该石墨矿进行粗选药剂条件试验,再以最佳药剂条件下浮选所得粗精矿为原料,研究不同再磨设备、再磨介质以及介质不同配比对保护石墨晶体的影响,结果表明,振动磨及柱介质对石墨晶体保护效果最佳。在最佳的再磨工艺条件下,进行粗精矿再磨细度、开路试验、中矿返回方式试验以及闭路试验,最终获得石墨精矿固定碳96.34%,回收率94.11%,+0.15mm级别产率16.17%(固定碳含量95.43%),尾矿固定碳0.69%的优良选别指标。
浮选机理分析表明,煤油主要以物理吸附方式吸附在石墨表面,在磨机中加入碳酸钠作为调整剂,既可以分散矿泥,还可以作为助磨剂提高磨矿效果。磨矿动力学理论研究表明,磨矿时磨矿介质的冲击力,容易使石墨鳞片发生垂直于结晶层面的断裂,此时,大鳞片石墨遭受破坏的几率大,而沿鳞片石墨结晶层面施加的碾磨或剥磨力,则容易使石墨鳞片沿结晶层面解离,此时大鳞片遭受破坏的几率小。因此选择磨剥及碾磨作用的振动磨,能更好地适应磷片石墨的层状结晶特性,既能大幅度地提高精矿品位,又能较好的保护大鳞片。
China is very rich in graphite, with reserves and production and sales volume ranking first in the world. Because of the unique physical and chemical properties, flake graphite has been widely available in the metallurgical, electrical, chemical and other industrial field. On the one hand, big flake graphite (usually+0.3 mm,+0.18 mm) has higher economic value than the fine grade,and some fields such as crucible and expanded graphite manufacturing must use big flake graphite, fine-grained level can not be used. We can not produce big flake graphite under modern industrial technology, once destroyed it can not be restored. On the other hand,big flake graphite in China is of low-scale,and the graphite flake is ususlly severely damaged due to the complex re-grinding process, leading to low yield and short market supply. Therefore, studying how to protect the graphite crystal during graphite flotation not to be destroyed and exploring reasonable re-grinding process to improve the big flake yield and the quality of concentrate has great economic significance on the full resources of graphite.
Process mineralogy studies on Graphite Mine in Anshan Xiuyan showed that the mine belonged to flake graphite ore, with fixed carbon content of 10.47%, mainly existing as scaly, single flaky or aggregates.The main gangue minerals are tremolite, quartz, mica, feldspar and so on. The results of disseminated characteristics of the graphite showed that the graphite mine contained 20%-30% of the+0.15 mm big particles.We should protect the big flake during mineral processing and improve the value of graphite products.
Firstly, research on pharmacy conditions of rough selection was carried out Then the effects of different re-grinding equipment, grinding media and different proportions of the media on the protection of graphite crystals were studied,with the crude concentrate as raw material which was obtained from crude flotation under the the best agents conditions.The results showed that the vibration mill and column media could provide The best protection effect on the crysta.Finally,on the base of the best re-grinding process conditions, the tests of the rough concentrate re-grinding degree, open trial, the way back of middlings mine and closed-circuit process were all carried out.Ultimately, high quality concentrate was obtained with concentrate fixed carbon content of 96.34%, recovery rate of 94.11%,+0.15 mm level yield of 16.17% (fixed carbon content of 95.43%), tailings fixed carbon of 0.69%.
Flotation mechanism showed that kerosene mainly adsorbed on graphite surface by physical adsorption, and adding sodium carbonate as a modifier in the mill can not only spread the sludge but also be used as aids to improve the grinding effect. Grinding kinetic theory studies showed that the impact force from grinding media may occur perpendicular fracture to the crystalline graphite flake,then would lead to more probability of big flake graphite destruction.The pan and peeling force along flake graphite crystalline level can make the flake graphite segregate easily along the dissociation level,then would decrease the probability of big flake damage.Therefore, vibration mill with the role of vibration and peeling was chosen as re-grinding equipment,which can better adapted to the layered crystalline characteristics of flake graphite.It can not only greatly improve the concentrate grade, but also provide better protection for big flake graphite.
引文
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[2]方莹,魏发灿.国外各国的石墨资源概况[J].耐火与石灰,2009,34(1)：62-63.
[3]王广驹.世界石墨生产、消费及国际贸易[J].中国非金属矿工业导刊,2006,(1)：61-65.
[4]杜庆洪,杨绍军.中国石墨行业现状及发展趋势[J].中国非金属矿工业导刊,2001,(6)：8-9.
[5]苑金生.我国石墨行业发展存在问题及改进措施[J].中国非金属矿工业导刊,2008,(1)：20-22.
[6]王志强,朱伯铨,方斌祥等.不同粒度的鳞片石墨对低碳镁碳耐火材料性能的影响[J].材料导报,2008,22(9)：139-144.
[7]S.Shaji, V.Radhakrishnan. An investigation on surface grinding using graphite as lubricant. International Journal of Machine Tools&Manufacture,42(2002)733-740.
[8]曹宏.浅论天然石墨行业的现状和发展方向[N].科技创业,2008(3)：71-72。
[9]陈小伟,牟春博,张慧.一种制备可膨胀石墨的新方法[J].中国非金属矿工业导刊,2009(1)：71-72
[10]Xianjunlu and E.Forssberg. Flotation selectivity and upgrading of Woxna fine graphite concentrate, Minerals Engineering,2001 (14) 1541-1543.
[11]屈启龙,谢建宏,王冠甫等.高碳钒矿综合回收石墨试验研究[J].矿业快报,2007(4)：35-37.
[12]刘渝燕,刘建国,魏健.某晶质石墨矿提高精矿大片产率及品位的选矿工艺研究[J].非金属矿,2003,26(1)：50-51.
[13]董凤芝.隐晶质石墨浮选研究[J].矿产保护与利用,1997(1)：15-18.
[14]肖奇,张清岑,刘建平等.某地隐晶质石墨高纯化试验研究[J].矿产综合利用,2005(2)：3-6.
[15]X.J.Lu, E.Forssberg. Preparation of high-purity and low-sulphur graphite from Woxna fine graphite concentrate by alkali roasting. Minerals Engineering 15(2002)755-757.
[16]Tegist Chernet, Mervi Wiik, Harri Lehto. The effect of micro-grinding and micro-graphite flotation to upgrade the quality of calcite concentrate, with reference to Kurikka calcite marble deposit, Finland. Minerals Engineering,19(2006)372-375.
[17]张清岑,刘建平,肖奇.微晶石墨除杂脱硅研究.非金属矿[J],2004,27(4)：1-3.
[18]李玉峰,赖奇,魏亚林等.细鳞片石墨的提纯研究[J].化工技术与开发,2007(10)：10-12.
[19]周春为,俞平胜,余志伟.宜黄细晶质石墨酸法提纯实验研究[J].东华理工学院学报,2007,30(2)：185-188.
[20]米国民,曹宪滨.鳞片石墨选矿工艺的进展[J].非金属矿,1993(1)：20-22
[21]谢朝学.保护大鳞片石墨选矿的研究[J].中国非金属矿工业导刊,2005(1)：45-48.
[22]司亚梅,吕一波.磨机中磨矿介质的运动规律[J].、中国非金属矿工业导刊,2006(5)：40-43.
[23]岳成林.小规模鳞片石墨矿浮选工艺研究[J].中国矿业,2007(12)：81-83.
[24]吴一善.鳞片石墨的浮选新工艺研究[J].非金属矿,1992,17(5).
[25]B.C.ACHARYA, D.S.RAO, S.PRAKASH. Processing of low grade graphite ores of orissa, India, Minerals Engineering,1996 (9) 1165-1169.
[26]衰慧珍,谢朝学.充填式浮选机选别鳞片石墨矿研究[J].非金属矿,1995(4)：18-32.
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