辉钼矿超声电氧化分解新工艺的研究
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
由于辉钼矿的焙烧氧化工艺存在着资源利用率低、金属综合回收率不高、释放的二氧化硫气体污染环境等弊端,而全湿法分解工艺操作条件苛刻、氧化剂消耗量大、运输困难、成本高,因此研究新的分解辉钼矿的分解方法势在必行。超声电氧化工艺就是以电氧化工艺为研究对象,将超声波外场强化与矿物的电氧化分解工艺有机结合,以求从根本上解决现存工艺的弊端,实现企业的清洁生产和提升企业的综合竞争能力。
     通过对电氧化工艺的机理以及试验研究的基础上,发现了电氧化工艺钼浸出率和电解电流效率低的原因:电极表面生成的惰性膜阻滞了反应的进行。而超声波产生微射流能削弱或减弱边界层,加大传质速度,破坏或溶解矿物表面的钝化膜和阻力膜,使矿物表面裸露出来,扩大反应界面。提出采用复合外场(电场+超声场)的方法来强化产物与浸出剂等的扩散、剥离、快速化学溶解或氧化来破坏惰性膜,促进辉铝矿电氧化浸出过程中电化学反应的顺畅进行。
     以石磨做电极用单因素试验和正交试验考察了电解质浓度、液固比、pH值和电解电压、电解时间对超声电氧化工艺的影响,得到了超声电氧化工艺分解辉钼矿的最佳工艺条件:在超声波作用方式为每隔15min发射3min、电解质NaCl浓度为20%、矿浆初始pH为10、电解电压为3.5v、矿浆液固比L/S为50、电解温度为25℃的条件下Mo浸出率和电解电流效率分别为:91.9%和191.8%。
     经试验研究发现石墨电极存在着能耗大、易损坏等弊端,因此对电解槽体系进行了设计与优化,优化后的电极以DSA做阳极,不锈钢做阴极,并在新的电解体系下对超声电氧化工艺条件作了进一步的试验研究,电压由3.5伏降低到了3.0伏,钼的浸出率由91.9%上升到了94.2%,电流效率上升到了196.5%。
     另外,本文阐述了超声波对电氧化过程的影响以及电流效率高的原因:超声空化作用能进一步分散矿浆,增加液固反应的活性中心,使电解产生的NaClO的利用效率增加;在超声场作用下,覆盖的硫膜极易被剥离,最终被电解产生的强氧化剂——NaClO所氧化而进入水相;矿浆中的溶解氧可以作为氧化剂参与辉钼矿的分解浸出过程;矿浆中矿物颗粒与阳极的碰撞可以导致辉钼矿的直接阳极氧化;超声空化产生强氧化性的羟基自由基(·OH,φ~0=2.8 v)直接参与氧化分解MoS_2(超声波有能量的给予,计算电流效率时未考虑了超声波电耗的消耗),同时提出了超声波作用下的反应机理。
According to the shortcomings of the roasting process (pollution of flue gas containing sulphur, poor metal comprehensive recovery) and clean process-hydrometallurgy of molybdenite, studying new decomposition method of molybdenite is necesary. Ultrasound electro-oxidation process was sudyied which can combine electric field and ultrasound on the basis of electro-oxidation process in order to solve the shortcomings of roasting process and process-hydrometallurgy.
     After studying the mechanism and experiments of electro-oxidation process,the reason of low Mo leaching rate and current efficiency was inert membranes during electro-oxidation process, which block the reaction.To promote electrochemistry reactions in electro-oxidation process for molybdenite, it's necessary that mass transfer among leaching agent, mineral and product should be strengthened by using of the coupling between electric field and ultrasound, so that inert membranes could be destroyed by the role of stripping, rapid dissolution or chemical oxidation.
     Ultrasound electro-oxidation process was studied using of carbon electrodes in self made cell. The optimal reaction conditions were obtained.The optimal conditions are as follows: the emission of ultrasonic of three minutes per 15 minutes, electrolyte concentration C_(NaCl) of 10%, pulp initial pH of 10, cell voltage of 3.5 v, temperature of 25℃, liquid to solid ratio L/S of 50. Current efficiency and Mo leaching rate can reach 91.9% and 191.8% under the optimal conditions.
     There were many shortcomings of carbon electrode according to the small size experiments. In order to further perfect the ultrasonic electro-oxidation process, its cell system was designed and optimized. Verification tests' results show that the new electrolysis device can achieve the coupling between electric field and ultrasound, and strengthen molybdenite oxidative decomposition and leaching. The voltage was decresed from 3.5V to3.0V. Mo leaching rate was increased from 91.9% to 94.2% and current efficiency increased to 196.5%.
     The influence of ultrasound to electrodes was studied. Reasonable explanation of high current efficiency in the electrolysis process in the novel process was put forward.The first reason is ultrasonic cavitation disperse pulp increasing activation center, which enhance the efficiency of hypochlorite. The second reason is inert membranes destroyed by the role of stripping, rapid dissolution and chemical oxidation entering solution. The third reason is that oxygen which dissolveing in solution decompose molybdenite. The fourth is the possibility of direct collision anodic oxidation and direct oxidation by ultrasound. The last one is that hydroxy oxidates and decomposes molybdenite. The mechanistic of decomposition molybdenite was brought forward at last.
引文
[1]李洪桂.湿法冶金学[M].长沙:中南大学出版社,2002:56-60.
    [2]佟升.钼及其合金的最新发展[J].中国钼业,1993,(4):13-16.
    [3]Yuill W A,Aria T.Process for converting molybdenite to molybdenum oxide[M].US 4551312,1985,11(5).
    [4 杨刘晓,许洁瑜.2005年中国钼工业发展状况[J].中国钼业,2006,30(2):3-6.
    [5]孙小白.试剂钼酸钠的制备[J].甘肃化工,1990,(4):6-8.
    [6]赵晓.提高钼精矿氧化焙饶合格率及钼收得率的几点措施[J].铁合金,1994,(6):32-33.
    [7]任宝江.回转窑焙烧钼精矿的生产实践[J].有色金属(冶炼部分),1999,(2):18-20.
    [8]魏守德,李文忠.回转窑焙烧钼精矿[J].铁合金,1989,(4):15-17.
    [9]McHugh L F,Barchers D E.Roasting of molybdenit concentrates containing flotation oils[M].US4523948,1985,(6):18.
    [10]任宝江.钼精矿回转窑隔层焙烧法[J].中国钼业,1999,23(3):40-42.
    [11]Sasaki I.Method for regenerating molybdenum-containing oxide fluidized-bed catalyst[M].US 6559085,2003,5(6).
    [12]Mahesh C J,May W A.Fluidized-bed roasting of molybdenites concentrates[M].US6190625,2001,2(20).
    [13]张文钲.用高新技术改造钼企业保持钼业可持续发展[J].钼业,2002,26(2):3-6.
    [14]William A Y,Tucson A.Process for converting molybdenite to molybdenum oxide[M].US4551312,1985,11(5).
    [15]James L L,John E L,Robert B C.Recovery of rhenium and molybdenum values from molybdenite concentration[M].US3770414,1973,11(6).
    [16]刘英汉.从含铼钼精矿中提取钼和铼的研究[J].江西大学学报,1989,13(1):88-95.
    [17]Trollhattan J W.Conversion of molybdenite concentrates to ferro-molybdenum and simultaneous removal of impurities by direct reduction with sulfide forming reducing[M].US4101316,1978,7(18).
    [18]赵业松.钼铁生产用氧化钼的焙烧方法[J].有色金属,1998,5(5):24-26.
    [19]Donald O B.Process for thermal dissociation of molybdenum disulfide[M].US3966459,1976,6(29).
    [20]《化工百科全书》编辑委员会.化工百科全书(第十二卷)[M].北京:化学工业出版社,1996,(3):113-118.
    [21]张相一,雷治州.提高钼酸按回收率的研究及实践[J].中国钼业,1997,21(2):76-79.
    [22]赵天丛.有色金属提取冶金手册·总论[M].北京:冶金工业出版社,1992,8(2):78-80.
    [23]Peinhard N L,Frank K F.Process for the production of molybdenum,molybdenum oxide produced from this process and use thereof[M].WO 02059042A1,2002,1(23).
    [24]赵中伟.辉钼矿湿法浸出过程某些理论问题之浅见[J].稀有金属与硬质合金,1995,122(6):1-3.
    [25]Derek G E.Hydrometallurgical production of technical grade molybdic oxide from molybdenite concentrates[M].US 3988418,1976,10(26).
    [26]Ketcham J.Pressure oxidation process for the production of molybdenum trioxide from molybdenite[M].US6149883,2000,11(21).
    [27]Sweetser J,William H,Leonard N.Process for autoclaving molybdenum disulfide [M].US5804151,1998,9(8).
    [28]魏绪钧译.用硝酸分解钼精矿[J].国外稀有金属,1983,(6):26-30.
    [29]李洪桂.辉钼精矿湿法浸出过程热力学探讨[J].钼业经济技术,991,(34):27.
    [30]张文钲.用高新技术改造钼企业,保持钼业可持续发展[J].中国钼业,2020,26(2):187-191.
    [31]Zhang Jiuxing.The Mechanism of Strengthening and Toughening of Rare Earth Molybdenum Alloy-roceeding of the13th International Plansee Seminar[J].Metallwerk,1993,5(10):14-16.
    [32]Brown I D,Altermatt D.Bond-valence parameters obtained from a systematic analysis of the inorgamic crystal structure database[J].Acta Cryst,1985,(41):244-247.
    [33]柯家俊.辉钼矿氧化浸取动力学研究[J].化工冶金,1982,(4):1-7.
    [34]曾庆衡主编.物理化学[M].长沙:中南大学出版社,1992:54-59.
    [35]刘光俊等.有色冶金进展[M].长沙:中南大学出版社,2001:121-125.
    [36]赵中伟.辉钼矿湿法浸出过程某些理论问题之浅见[J].稀有金属与硬质合金,1995,122(6):1-3.
    [37]utierrez M,Henglein A.Chemical action of pulsed ultrasound:observation of an unprecedented intensity effect[J].Journal of Physical Chemistry,1990,94(9):3625-3628.
    [38]冯若,李化茂.声化学及应用[M].合肥:安徽科技出版社,1992:23-25.
    [39]顾衍,李洪桂.辉钼矿湿法浸出新工艺研究[J].中国钼业,1997,21(5):29-33.
    [40]赵吉波.超声波强化铝酸钠溶液分解过程的机理研究[M].长沙:中南大学出版社,2004:10-15.
    [41]uttner J,Gutierrez M,Henglein A.Sonolysis of water-methanol mixtures.Journal of Physical Chemistry[J],1991,95(4):1528-1530.
    [42]向铁根.钼冶金[M].长沙:中南大学出版社,2002:69.
    [43]陈延禧编著.电解工程[M].天津:天津科学技术出版社,1993:160-163.
    [44]Prem Krishnaswamy.Kinetics of the aqueous oxidation of molybdenite and the role of crystal anisotropy on the electrochemical mechanism of the process[J].University of California,1981,4(8):10-12.
    [45]杨雨浓译.很有希望的铜精矿综合处理工艺[J].稀有金属与硬质合金,1991,106(9):24-27.
    [46]Joanna L H,Jon C B,Qi Hong.Sonoelectrochemical and sonochemical effects of cavitation:correlation with interfacial cavitation induced by 20 kHz ultrasound[J].Ultrasonics Sonochemistry,2000,(7):7-14.
    [47]Gedanken A.Using sonochemistry for the fabrication of nanomaterials[J].Ultrasonics Sonochemistry,2004,11(2):47-55.
    [48]Nakanishi M,Takatani H,Kobayashi Y.Characterization of binary gold/platinum nanoparticles prepared by sonochemistry technique[J].Applied Surface Science,2005,241(1):209-212.
    [49]黄宝茅,程光荣.用萃取法从尾矿次氯酸钠浸出液中回收钼酸氨研究[J].湿法冶金,1995,56(4):1-8.
    [50]冯若,李化茂.声化学及应用[M].合肥:安徽科技出版社,1992:20-24.
    [51]Lorime J P,Mason T J.Sonochemistry:part Ⅰ thephysical aspects[J].Chemical Society Reviews,1987,16(2):239-274
    [52]Cognet P,Wilhelm A M,Delmas H.Ultrasound in organic electro-synthesis[J].Ultrasonics Sonochemistry,2000,(7):163-167.
    [53]uttner J,Gutierrez M,Henglein A.Sonolysis of water-methanol mixtures[J].Journal of Physical Chemistry,1991,95(4):1528-1530.
    [54]Hua I,Hofmann M R.Kinetics and mechanism of the sonolytic degradation of CCl_4:intermediates and byproducts[J].Environmental Science Technology,1996,30(3):864-871.
    [55]安国驹,陈之川译.电解槽工学[M].北京:化学工业出版社,1985:250-262.
    [56]胡耀红,陈力格.DSA涂层钛阳极及其应用[J].电镀与涂饰,2003,22(5):58-59.
    [57]谢素玲.高性能多用途的DSA阳极[J].电镀与涂饰,2004,23(3):50-53.
    [58]石绍渊,孔江涛,朱秀萍.钛基Sn或Pb氧化物涂层电极的制备与表征[J].环境化学,2006,23(4):429-433.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700