輝鉬礦濕法冶金新工藝及其機理研究_圖文

1、分類號VDC博士學位論文 輝鉬礦濕法冶金新工藝及密級其機l 73S 259理研究The research on novel hydrometallurgy for molybdenite concentrate and its mechanisms作者姓名:曹占芳學科專業(yè):化學工藝學院(系、所:化學化工學院指導教師:鐘宏教授答辯委員會主席地中 南大學2010年5月”.、:一:、 .1o原創(chuàng)性聲明本人聲明,所呈交的學位論文是本人在導師指導下進行的研究 工作及取得的研究成果。盡我所知,除了論文中特另tl;Dl:l以標注和致謝 的地方外,論文中不包含其他人已經(jīng)發(fā)表或撰寫過的研究成果,也不 包含為獲得

2、中南大學或其他單位的學位或證書而使用過的材料。與我 共同工作的同志對本研究所作的貢獻均已在論文中作了明確的說明。作者簽名:j嶂 日期:扯年土月立日 學位論文版權(quán)使用授權(quán)書本人了解中南大學有關(guān)保留、使用學位論文的規(guī)定,即:學校 有權(quán)保留學位論文并根據(jù)國家或湖南省有關(guān)部門規(guī)定送交學位論文, 允許學位論文被查閱和借閱;學?？梢怨紝W位論文的全部或部分內(nèi) 容,可以采用復印、縮印或其它手段保存學位論文。同時授權(quán)中國科 學技術(shù)信息研究所將本學位論文收錄到中國學位論文全文數(shù)據(jù)庫, 并通過網(wǎng)絡向社會公眾提供信息服務。期a盟翌年月受日 博士學位論文 摘要 摘要針對現(xiàn)有輝鉬礦焙燒工藝污染嚴重,且難以實現(xiàn)鉬及伴生金

3、屬高 效經(jīng)濟回收的弊端,進行了輝鉬礦常溫常壓濕法浸出和浸出液中鉬、 錸的分離富集及其機理的研究,為發(fā)展環(huán)境友好的鉬濕法冶金新工藝 提供理論基礎?；诤趼人猁}在溶液中具有高的電極電位,表現(xiàn)出很強氧化能 力的特性,對氯酸鈉和次氯酸鈉氧化分解輝鉬礦、黃銅礦等進行熱力 學計算。結(jié)果表明,氯酸鈉、次氯酸鈉氧化分解輝鉬礦、黃銅礦等過 程的G0值均為負值,且絕對值較大,說明氯酸納、次氯酸鈉都能 應用于對輝鉬礦的氧化分解。研究了氯酸鈉氧化分解輝鉬礦的行為與規(guī)律,發(fā)明了一種使用電 解氯化鈉鹽水生成的氯酸鈉電解液為氧化劑、在酸性水溶液條件下高 效氧化分解輝鉬礦精礦的新方法。以氯酸鈉為氧化劑,在 C(NaCl=0

4、.71mol/L,C(H2S04=73.3L,NaCl03/MoS2=3.6(mol/m01, L/S=30,T=70,攪拌速率為400r/min,t-6h的條件下,鉬的浸 出率為98.62%,錸的浸出率為99.52%,銅的浸出率為99.77%,鐵的 浸出率為99.28%,實現(xiàn)了多種硫化礦物的全分解。在對氯酸鈉氧化 分解輝鉬礦研究的基礎上,將電化學合成的氯酸鈉電解液,不經(jīng)凈化、 結(jié)晶等操作,調(diào)整酸度后直接用來浸出輝鉬礦。優(yōu)化確定采用的氯酸 鈉電解合成工藝條件為:槽電壓3.O V,電流密度653.2A/m2,攪拌 速度100r/min,Na2Cr207濃度3g/L,pH=6.7,溫度75,電解時

5、 間35h,此時電解液含氯酸鈉290.90g/L,含次氯酸鈉7.08g/L,鉬、 錸浸出率分別為98.51%和99.56%。采用氯酸鈉電解液濕法氧化分解 輝鉬礦的方法具有氧化劑生產(chǎn)成本低、使用安全等優(yōu)點。浸出動力學 研究表明浸出過程符合收縮核模型,表觀活化能Ea=104.6kJ/mol,過 程受化學反應控制。氯化鈉濃度4mol/L,碳酸鈉6g/L,碳酸氫銨5g/L,緩沖體系pH=8.59.5, 室溫的條件下,電解240min時鉬浸出率可達99.35%,錸浸出率為 99.79%,電流效率為62.75而非緩沖體系電氧化工藝達到同樣鉬浸 出率時電流效率僅為40.44%。通過緩沖體系的應用,使鉬精礦中

6、鉬、 錸選擇性高效氧化浸出,而黃銅礦基本不浸出,浸出渣中銅含量為 10.84%,回收率達到97.93%。緩沖體系中電氧化工藝是一種更為高效 環(huán)保的輝鉬礦選擇性電氧化分解工藝。該工藝特別適用于德興銅礦高 銅鉬精礦的的濕法分解。通過對電氧化過程陽極氧化、氧化劑變化規(guī)律的研究,建立了電 氧化浸出過程的動力學模型,揭示了緩沖體系中電氧化分解輝鉬礦的 浸出機理。結(jié)果表明,輝鉬礦在陽極上不能直接被氧化,NaCl介質(zhì) 中析氯反應起了主導作用,輝鉬礦的氧化浸出主要是借助于陽極析出 的氯氣轉(zhuǎn)化生成的氧化劑,氧化劑主要成分是NaCl0。浸出動力學 研究表明,pH=9的碳酸鹽一酸式碳酸鹽緩沖體系中,輝鉬礦的浸出表

7、觀活化能E=8.56kJ/mol,過程受固膜擴散控制。采用溶劑萃取技術(shù)對輝鉬礦浸出液中的Mo(VI、Re(VII進行了萃 取與反萃研究,建立了萃取反應模型方程,揭示了萃取劑N235對鉬、 錸金屬離子的萃取機理。在優(yōu)化的萃取條件下,氯酸鈉電解液浸出輝 鉬礦溶液經(jīng)3級萃取后,Mo(VI、Re(VII的萃取率分別達到99.84%和95.19%;采用17%的氨水為反萃劑,在優(yōu)化的反萃條件下,3級 反萃后Mo(VI、Re(VII的反萃率分別達到99.90%和99.73%。在優(yōu) 化的萃取條件下,電氧化分解輝鉬礦浸出液經(jīng)3級萃取后,Mo(VI、 Re(VII的萃取率分別達到99.77%和94.73%;采用1

8、7%的氨水為反萃 劑,在優(yōu)化的反萃條件下,3級反萃后Mo(VI、Re(VII的反萃率分 別達到99.89%和99.54%。等摩爾法實驗和紅外光譜分析表明,N235萃取Mo(VI、Re(VII離子時,叔胺基與溶液中的離子發(fā)生了配位反 應,分別以(R3NH2(M0022(S043an RaNHRe04形式進行萃取。 采用D201樹脂對反萃液中的Mo(VI、Re(VII吸附分離性能進 行了考察,建立了樹脂吸附動力學和熱力學模型,揭示了陰離子交換 樹脂對Mo(VI、Re(VII的吸附機理。靜態(tài)吸附實驗表明,D201樹脂 對Mo(VI、Re(VII的吸附容量都隨吸附時間和金屬離子初始濃度的 增加而增大。

9、靜態(tài)分離實驗表明,樹脂對溶液中的Re(VII具有良好 的吸附選擇性,溶液中Mo(VI初始濃度越大分離因子越高。對氯酸 鈉浸出體系反萃液,在吸附溫度30,pH=8,吸附時間l h條件下,IIRe(VII、Mo(VI吸附率分別為92.4l%、3.19%,分離因子為190.49; 對電氧化浸出體系反萃液,在吸附溫度30,pH=8,吸附時間1h 條件下,Re(VII、Mo(VI吸附率分別為92.18%、3.46%,分離因子 為169.56。實驗數(shù)據(jù)符合Boyd液膜擴散方程,樹脂對Mo(VI、Re(VII 的吸附過程屬于液膜擴散控制過程。吸附過程為單分子層吸附,符合 Langmuir和Freundlic

10、h等溫吸附模型,根據(jù)擬合結(jié)果計算得到的D201樹脂對Mo(VI、Re(VII的飽和吸附容量分別為4.2633mmol/g、4.2355 mmol/g。全流程技術(shù)經(jīng)濟分析表明,與傳統(tǒng)焙燒工藝相比,緩沖體系電氧 化浸出工藝是一種高效環(huán)保的輝鉬礦濕法分解工藝。對于德興銅礦的 輝鉬精礦,鉬回收率達到99.04%,錸回收率達到85.84%,銅回收率 超過97%,年凈增經(jīng)濟效益2000多萬元,減排S022681t/年,具有 明顯的經(jīng)濟效益和環(huán)境效益。關(guān)鍵詞輝鉬礦,濕法浸出,氧化分解,萃取,吸附III 博+學位論文AB STRACTThe roasting method gradually shows it

11、s shortcomings.During roasting,many valuable metals are lost due to volatilization and the S02 generated is a source of environmental pollution.The novel cold atmospheric leaching of molybdenite,the process of extraction and separation of molybdenum and rhenium in the extract,and their mechanism hav

12、e been investigated,providing theoretical basis for environment-friendly hydrometallurgy of molybdenite.Chlorate and hypochlorite in solution have high electrode potential and strong oxidative property.Thermodynamic calculations of the oxygenolysis process of molybdenite by sodium chlorate and sodiu

13、m hypochlorite were carried out.The results showed that valuesofG。 were negative and the absolute values of them were high if sodium chlorate and sodium hypochlorite were used as oxidant in the molybdenite leaching process.In the view of thermodynamic point,MoS2, CuFeS2,FeS2and ReS2etc.could be leac

14、hed by acidic chlorate system and alkaline sodium hypochlorite system theoretically.In this paper,the technology of molybdenum extraction from molybdenite concentrate by using sodium chlorate has been investigated, and a novel hydrometallurgical extraction technology of molybdenite by using sodium c

15、hlorate electrolyte was introduced.The optimized leaching conditions are as followed:C(NaCl=0.71mol/L,C(H2S04=73.3g/L, NaCl03/M082=3.6(mol/m01,L/S=30,T=70,stirring rate is 400 r/min,t-6h.Under these conditions,leaching yield of molybdenum is 98.62%,leaching yield of copper is 99.77%,leaching yield o

16、f iron is 99.28%,leaching yield of rhenium,99.52%;while leaching of molybdenite is completed,Cu,Fe,Re were almost completely leached into the liquid.The acidic sodium chlorate electrolyte by electrochemical synthesis,without purification,crystallization,but just adjust the acidity and was directly u

17、sed for leaching of molybdenite.The optimized electrosynthesis conditions of sodium chlorate are as followed:cell voltage of 3.0V current density of 653.2A/mz,stirring rate of 100r/min, IV博士學位論文concentration of potassium dichromate of 3g/L.pH=6.7,75,35h. Under this electrosynthesis conditions,sodium

18、 chlorate iS 290.90vet.。 sodium hypochlorite is 7.08L,leaching yield of molybdenum is 98.51%.and leaching yield of rhenium iS 99.56%.It was an efficient and economic wet leaching process that sodium chlorate electrolyte was used for leaching molybdenite,and it can also reduce cost largely.The kineti

19、c study showed that the process of leaching molybdenite using acid sodium chlorate system is represented by shrinking core model,the apparentleaching process.Anode oxidation and oxidant have been investigated.and dynamic model of leaching process was established.The results showed thatmolybdenite co

20、uldnt be electro.oxidated at the anode directly in the bu虢r system.The chlorine evolution reaction hasplayed a dominant role V博士學位論文in sodium chloride medium.Sodium hypochlorite iS the main oxidant of oxidation leaching,which transformed from chloration liberated at the anode.The kinetic study showe

21、d that a shrinking core model is presented to describe the dissolution and to analyze the data.It was established that the leaching process is mainly controlled by diffusion through a porous product layerthe apparent activation energy of this dissolution process was found to be 8.56kJ/m01.The studie

22、s on extraction of Mo(VI,Re(VIIin the solution and its mechani sm by using N235extractant have been investigated.For extract solution of sodium chlorate,the percentage extraction rates of Mo(VI and Re(VIIunder the optimized extraction conditions were about 99.84%and 95.19%;Stripping of molybdenum to

23、 aqueous phase was efficient when 17%ammonia liquor were applied,the Mo(VIand Re(VIIstripping efficiencies under the optimized stripping conditions were about 99.90%and 99.73%.For electric-oxidation extract solution, the percentage extraction rates of Mo(VIand Re(VIIunder the optimized extraction co

24、nditions were about 99.77%and 94.73%; Stripping of molybdenum to aqueous phase was efficient when 17% ammonia liquor were applied,the Mo(VIand Re(VIIstripping efficiencies under the optimized stripping conditions were about 99.89% and 99.54%.The results of equimolar seriers method and infrared spect

25、ral analysis indicates that the coordinate reactions in aqueous solution happened while N235extracted Mo(VIand Re(VIIions, (R3NH2(M0022(S043and R3NHRe04come into being,respectively。 The adsorption and separation capability for Mo(VIand Re(VII ions of D201resin have been investigated,adsorption kinet

26、ics and thermodynamics were revealed by analyzing adsorption data.The results showed that the adsorption capacity of D201for Mo(VIand Re(VII ions increases with increase in adsorbing time and the initial ions concentration.For dualistic mixed solution of Mo(VIand Re(VII,the separation capability of

27、D201for Re(VIIand Mo(VIhas been investigated,it indicates that D201has excellent adsorption selection for Re(VIIions,and satisfy the separation demands.For stripping solution of sodium chlorate system,the adsorption rate of Re(VIIand Mo(VIareVl博士學位論文 ABSTRACT92.4l%,3.19%,respectively,and separating

28、factor is 190.49,when adsorption condition is 30,pH=8,and absorbing time 1h;For stripping solution of electric-oxidation system,the adsorption rate of Re(VIIand Mo(VIare 92.18%,3.46%,respectively,and separating factor is 169.56,when adsorption condition is 30,pH=8,and absorbing time 1h.The experimen

29、tal data fit BoydS diffuse equation of liquid film,indicating that the adsorption is controlled by liquid film diffuse;the isothermal adsorption obeys Langmuir and Freundlich equation,especially the former equation.The saturated adsorption capacity of D201for Mo(VIand Re(VIIcalculated base on simula

30、ted results were 4.2633mmol/g,4.2355mmol/g,respectively.The results of rough cost and economic analysis for molybdenite of Dexing CopperMine showed that,compared to conventional roasting process,the overall yield of molybdenum is 99.04%,the overall yield of rhenium is 85.84%,increase the recovery fo

31、r rhenium by 25%,and more than 97%copper can be recovered,The newincreased income is over 2000million yuan per annum,the reduced quality of S02is 2681t per annllm.KEY WORDS molybdenite,hydrometallurgy,oxygenolysis,extraction, separationVlI博士學位論文 目錄 目 錄博士學位論文 目錄博士學位論文 目錄博士學位論文 目錄博士學位論文 目錄V博士學位論文 目錄1.

32、1引言第一章緒論鉬是一種稀有難熔金屬,在元素周期表中屬于第六副族,1778年瑞典化學 家用硝酸分解輝鉬礦發(fā)現(xiàn)了元素鉬,并首次分離出鉬酸和制取了若干種鉬酸鹽。 金屬鉬具有高強度、高熔點、耐腐蝕、耐磨研等優(yōu)劇2硼。工業(yè)上以二硫化鉬、 鉬酸鹽、金屬鉬、低合金鉬基材料以及高合金鋼的形式廣泛用于各部門,如機械、 汽車、航天、航空、宇宙開發(fā)、石油化工、食品、防腐、塑料、復合材料、真空 工程、化工、電氣和電子技術(shù)、冶金機械、醫(yī)藥、農(nóng)業(yè)等【71。目前己知的鉬礦物大約有20多種,但其中具有工業(yè)應用價值的僅有四種, 即輝鉬礦(MoS2、鉬酸鈣礦(CaM004,鉬酸鐵礦(Fe2033M003-7H20和鉬酸鉛礦 (

33、PbM004。所有鉬礦物中,輝鉬礦的工業(yè)價值為最高,分布最廣,約有99%的 鉬呈輝鉬礦的形式存在,占世界開采量的90%以上。輝鉬礦是鉬最主要的礦石 來源,它是一種質(zhì)軟并帶有金屬光澤的鉛灰色礦物,外觀與石墨相似,呈鱗片狀 或薄板狀的晶體,具有層狀六角型晶格,圖1.1為其結(jié)構(gòu)示意圖【3】。輝鉬礦是已 知含錸(Re最高的礦物。錸與鉬的離子半徑相近,故錸經(jīng)常置換鉬而富集于 輝鉬礦中,成為錸的主要工業(yè)來源。錸主要從鉬精礦的氧化焙燒煙氣淋洗液或濕 法浸出液中進行回收,通過萃取法或離子交換法制成高錸酸鉀或高錸酸銨,經(jīng)還 原法得到金屬錸粉【8】。錸是銀灰色的金屬,熔點高達3180,在金屬中僅次于 鎢,居第二位

34、。錸非常硬、耐腐蝕、耐磨且有良好的延展性。特別是由于其呈密 排的六方晶體結(jié)構(gòu),可在低溫下保持它的硬度和延展性且在高溫和溫度驟變情況 下保持高的強度和良好的抗蠕變性能f9J。9I 一Il 一國k。 滋夸l I 1Ll.一I:=;一涔泌廠r 麗 一 I、,I圖1-1輝鉬礦的結(jié)構(gòu)焙燒一氨浸工藝是鉬的經(jīng)典冶金工藝,焙燒使輝鉬礦中Mo氧化轉(zhuǎn)變成為氨 溶性的M003,20世紀70年代之前世界上幾乎90%純鉬化合物的生產(chǎn)都是采用該 類工藝【lo】。無論是經(jīng)典的焙燒氧化工藝還是改進的焙燒氧化工藝,以及近年來 發(fā)展起來的新的鉬冶金工藝都存在流程長、原料消耗高、金屬回收率低、環(huán)境污 染嚴重及許多貴金屬難回收或回收

35、率極低等缺點。20世紀70年代以來,國內(nèi)外竟 相開展了輝鉬礦全濕法新工藝的研究,其核心是在礦漿狀態(tài)下將輝鉬礦氧化轉(zhuǎn)化 成為鉬的氧化物或其鹽,其優(yōu)勢在于能處理各種品位的鉬礦物,適應性廣,避免 了焙燒工序從而有效解決ys02氣體的環(huán)境污染問題【12卅71。鉬礦物經(jīng)濕法分解后 可通過溶劑萃取或離子交換等新型分離技術(shù)回收,縮短了工藝流程,同時也能高 效綜合回收多種伴生有價金屬,如錸等11。全濕法分解工藝將成為一種環(huán)境友 好的輝鉬礦主要冶金方法【1823j。本課題來源于“十一五”國家科技支撐計劃項目“德興銅礦資源高效開發(fā) 利用關(guān)鍵技術(shù)研究(2007BAB22801。以德興銅礦自產(chǎn)的高銅高錸輝鉬精礦為 研

36、究對象,進行輝鉬精礦濕法分解新工藝研究,為發(fā)展環(huán)境友好的鉬濕法冶金新 工藝提供技術(shù)原型;研究萃取、離子交換等分離富集技術(shù),實現(xiàn)鉬、錸、銅的高 效分離與綜合回收。1.2輝鉬礦氧化分解工藝焙燒一氨浸工藝是鉬的經(jīng)典冶金工藝,焙燒的目的是使輝鉬礦中二硫化鉬的 鉬硫分離開來,使不溶于氨水的二硫化鉬經(jīng)過焙燒后轉(zhuǎn)化為易溶于氨水的三氧化 鉬。具體工藝流程見圖1-231。2博士學位論文 第一章緒論 輝鋁精礦T工業(yè)M003(焙砂T_一殘渣廠堿溶或酸溶回收Mo鉬酸氨溶液渣(含Cu、Fe、等硫化物純鉬酸氨溶液仲鉬酸銨=圖1-2鉬提取的經(jīng)典工藝流程該工藝是將輝鉬礦在600-,700下進行氧化焙燒,得到的鉬焙砂(主成分

37、為M003經(jīng)氨浸、凈化、酸沉、結(jié)晶等工序處理,轉(zhuǎn)化成為鉬酸銨產(chǎn)品。20世紀60-,70年代期間,世界上幾乎90%的純鉬化合物的生產(chǎn)都采用此工藝【2牝81, 主要原理見方程式1.1:MoS2+3.502=M003+2S02(11 3博士學位論文 第一章緒論浸出是使工業(yè)M003粉中可溶鉬溶于氨水,生成鉬酸銨溶液,其反應方程式 見式1.2:M003+2NH3-H20=(NH42M004+H20(1-2 其它不溶性雜質(zhì),如CalVl004、PbM004、Si02、Fe203等殘留在渣中,達到 鉬和大部分雜質(zhì)分離。氨浸出在固液比0.52.5,溫度仲胺叔胺的順序下降。季銨不能發(fā)生直接配位的反應。(4鰲合萃取劑鰲合萃取劑廣泛應用在分析化學中,具有