高炉炉缸内碳氮化钛的生成机理研究

从热力学和热模拟试验两个方面研究了碳饱和铁浴内碳氮化钛的生成机理。利用CONFOCAL激光高温显微镜的试验数据重新确定了钛在碳饱和铁浴内的溶解度和碳氮化钛形成所需的最低钛含量。结果表明在碳饱和铁浴内生成碳化钛和氮化钛的最低钛含量较采用现行热力学数据计算的结果要低。采用长坩埚法研究了不同温度梯度条件下碳氮化钛的形成，结果发现碳氮化钛在温度梯度较大的耐火材料和铁水界面有团聚行为     

钛精矿碳热还原制备碳氮化钛的研究

以钛精矿和石墨为原料,在氮气气氛下通过碳热还原法制备出碳氮化钛(Ti CN)粉体。结合XRD、SEM、化学成分分析和TG-DSG综合热分析研究了配碳量及反应温度对钛精矿碳热还原进程的影响。研究结果表明,配碳量的增加影响逐级还原反应温度以及反应总失重,当配碳量达到23%时碳氮化钛产物中出现游离碳。钛精矿碳热还原过程中铁氧化物优先还原,钛氧化物经逐级还原形成Ti CN,还原顺序为Ti O2→Ti4O7→Ti3O5→Ti N→Ti(C,N,O)→Ti CN。得到的碳氮化钛粉体呈微米级不规则形状。     

含铌尾矿中铁与铌的分离与回收

在热力学分析的基础上,通过碳热还原和磁选分离对白云鄂博含铌尾矿中铁的回收与铌的富集进行探索性研究。结果表明,在1 000~1 100℃下,以碳为还原剂进行焙烧可以对含铌尾矿中的铁氧化物进行选择性还原。1 100℃焙烧0.5h并经湿磨后在50mT的磁场强度下磁选,可实现铁精粉与含铌矿物的分离。磁选所得铁精粉中铁品位为84.82%,铁收得率为81.95%,磁选尾矿中铌品位为1.98%,铌回收率达到95%以上。     

钛微合金钢中碳氮化钛固溶量及化学组成的计算与分析

根据相关热力学理论,提出了钛微合金钢中钛、碳、氮元素在奥氏体中的平衡固溶量及平衡沉淀析出的碳氮化钛的化学式系数的理论计算方法,对典型化学成分的钛微合金钢进行了理论计算并对计算结果进行了分析.结果表明,通常情况下在较高温度析出或未溶的碳氮化钛相当接近于TiN.     

高钛渣提取碳氮化钛的研究

在热力学分析基础上,以攀钢高钛渣为基准配制的TiO2-CaO-SiO2-Sl2O3-MgO五元合成高钛渣为主要原料,采用碳热还原法制取碳氮化钛.确定了碳化处理过程中不同气氛(氩气,氮气)下的产物,采用X-射线衍射仪和扫描电镜研究了产物的相组成和显微结构,证实了在氩气气氛下,产物主要为TiC;在氮气气氛下,产物主要为Ti(C,N);氩气气氛下碳化钛的粒度比同一实验条件氮气气氛下碳氮化钛的粒度要小2～4μm.     

碳热还原法制备Ti(C,N)粉末

研究了用淀粉作为碳源还原氢化钛制备碳氮化钛纳米粉的工艺及利用热力学计算分析了反应机理。结果表明 :在实验范围内 ,降低合成温度、缩短保温时间或提高氮气流量有利于形成氮含量高的碳氮化钛粉末。通过控制合成温度和保温时间 ,可以控制Ti(C1 -xNx)中的碳氮比 ,得到不同x值的碳氮化钛粉末。实验结果与理论计算相一致     

水解沉淀-碳热还原氮化法制备碳氮化钛粉末

以四氯化钛、炭黑为原料,利用水解沉淀-碳热还原氮化法制备了碳氮化钛粉末.利用差热分析、X射线衍射及扫描电镜等表征手段,研究了合成工艺对粉末物相、组成及形貌等的影响.结果发现:前驱体粉末经350 ℃煅烧2h后,钛以TiO2的形式存在,TiO2与炭黑形成了混合均匀的团聚体:在碳热还原氮化反应时,钛氧化物向TiCxNyOz转...     

从0.8米~3高炉解剖看钒钛烧结矿在高炉内还原过程及其渣铁形成特点

作者对钒钛烧结矿小高炉冶炼解剖试样,进行了工艺岩石学初探,提出了钒钛烧结矿在炉内还原相变历程图,研究了碳氮化钛生成机理和存在状态以及渣铁形成相变特点。指出了碳氮化钛主要在风口区渣焦接触反应生成,渣铁反应生成碳氮化钛是很次要的。渣中大量碳氮化钛固体微粒和铁珠吸附碳氮化钛包壳导致炉渣性能恶化、渣铁难分。因此,强化喷吹,改革炉型,提高炉缸氧住,消除碳氮化钛影响对强化钒钛矿高炉冶炼是很有意义的。     

惰气熔融-热导法测定高含氮量碳氮化钛粉末中氮含量

由于传统碳氮化钛中氮元素的测量方法有一定局限性,仅在氮含量5%及以下时才能保证测量精度,基于此,建立了一种惰气熔融-热导法测定高含氮量碳氮化钛粉末中氮含量的方法,可有效解决传统方法的不足,检测上限可增加至14%。检测设备使用ONH分析仪,测试条件优化为试样称取0.1 g,助熔剂采用0.65 g镍囊与0.16 g锡囊组合形式,将试样与助熔剂混合置于高温石墨坩埚内,载气可将熔融状态下释放的氮气输送至热导池进行含量测定。此外,采用“分段式升温”方法,调节仪器分析功率,由1.5 kW梯度增加至3.8 kW,可有效增加试验样品中氮元素的释放率及测量稳定性。测量结果采用钒氮合金与氮化钒铁标样确定样品中氮的校正参数,测定结果的相对标准偏差为0.3%,分析结果与蒸馏滴定法的测定结果一致,该方法的准确度及稳定性完全能满足5%～14%的高含氮量碳氮化钛的测定需要。     

通过添加钛细化S45C钢铸态奥氏体显微组织

本文研究了添加钛对铸态奥氏体（γ）结构的影响,不添加钛的铸态γ结构由粗大柱状晶粒组成。添加钛可促使等轴γ-晶粒的形成,也能细化γ结构晶粒。仅当钛加入量介于0．13％-0．17％狭小范围时,方可形成全部等轴晶和非常细小γ-晶粒结构。相图热力学计算结果表明：在此组成范围内,碳氮化钛作为初晶相结晶,通过初始碳氮化钛微粒诱导在δ-枝晶凝固过程中,从柱状晶到等轴晶转变（CET）时形成非常细小的等轴γ-晶粒结构,这些微粒是等轴δ-枝晶形核场所。试验结果表明,细小碳氮化钛的存在可以阻止包晶转变后γ-相的晶粒长大,其可导致铸态γ-结构的细化。     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.     

Seven Rare Earth Projects Involving Close to 3 Billion Yuan Investment Landed In the HighTech Zone

正On May 22,Baotou Rare Earth Industry Cooperation Consultation MeetingProject Agreement-signing Ceremony was held in Ningbo,nearly 40 enterprises from Ningbo,Guangdong,Hunan,and Shanxi participated in project consultation.After multi-lateral communication,agreements were signed for a total of 7 rare earth projects successfully.