酸碱容量法测定碳化钙

碳化钙(电石)的测定,有采用气体发生法以测定所产生的乙炔气的体积,加以换算。此法对低含量的物料误差很大,且需一套特殊装置,并需用乙炔饱和过的氯化钠溶液,不宜采用。 用酸碱容量法进行碳化钙的测定,其方法原理系基于碳化钙与水作用,所生成的乙炔气与硝酸银反应后形成定量的硝酸,     

碳化钙中磷的测定

碳化钙 (俗称电石 )是焦炭、生石灰在电炉中于强热下生成的。碳化钙是坚硬的块状物 ,遇水时迅速分解 ,生成乙炔 ,同时大量发热。由电石制得的乙炔浓度很高。但电石中常含有S ,P ,As,Si等杂质。所以生成的乙炔气中也常含有H2 S ,PH3等 ,在参加合成反应时应予清除。乙炔是最基本的有机原料之一 ,故乙炔也被人称为“有机合成的基石” ,而其中磷的含量也应尽量小。本法将试样溶解后 ,以高氯酸冒烟将磷氧化为正磷酸 ,并以磷铋钼蓝光度法测定磷。1　实验部分1 1　主要仪器和试剂72 1型分光光度计。碳酸钠 -碳酸钾 -硼酸 ( 3+ 1 + 2 ) :将 3份…     

采用碳化钙冶炼低碳钢

现代化冶金工业寻找的不仅是技术有效的工艺，而且也是有经济效益的工艺。炼钢生产难以实现的课题之一是在浇铸前尽可能最大限度地降低非金属夹杂物，来保证连铸时良好的流动性并因此保证钢材质量。众所周知，在炉外处理过程中没有很充分地去除非金属夹杂物。因此在脱氧前用一切可能的方法合理限制钢水的氧化度从而来降低脱氧时形成的非金属夹杂物数量。碳化钙，因为是还原剂，能降低钢包渣的氧化潜力，脱氧剂的烧损和非金属夹杂物量。CaO，作为CaC2的分解产物，能提高渣碱度，提高钢水炉外处理各阶段钢水的脱硫速度和脱硫率。炼低碳钢时根据钢包添加CaC2量，会导致钢水中碳含量的增长。     

复合球团制备碳化钙数学模型研究

综合考察了复合球团制备CaC2过程中化学反应和热量传递两种因素对CaC2生成速率的影响.通过研究各级化学反应和不同环境温度对反应过程的影响规律,建立了单一含碳球团还原生成CaC2的一维模型.模型求解结果表明,在环境温度为1 923～2 073 K范围内时,整个反应的速控环节是CaC2的生成反应,且环境温度越高速控环节所受影响越低.另外,球团内部热量传递对化学反应速率影响较小,最终确定了反应时间和温度对生成CaC2速率的影响规律.     

氧化锂真空碳化钙热还原提取锂的研究

研究了以碳酸锂为原料，在低压以及温度为1273K－1423K范围内用碳化钙为还原剂还原氧化锂以提取金属锂的试验，试验考察了温度和时间对锂取率的影响，得出：从还原速度，产率，锂的纯度等指标来看，碳化钙是一种较优越的还原剂。     

光度法和滴定法在碳化钙合金测定中的应用

以碱性混合熔剂熔融试样,酸化浸取、定容,移取部分试液,通过控制测定各元素时的酸度,分别用硅钼蓝光度法测定硅,高锰酸光度法测定锰,磷铋钼蓝光度法测定磷,分析结果均在允许误差范围内。剩余试液加三乙醇胺及半胱氨酸掩蔽铁、铝及锰等元素的干扰,以氢氧化钾溶液调节批p H值大于12.5,加钙指示剂,用EDTA标准溶液滴定碳化钙量,取得了令人满意的结果,相对标准偏差小于0.2247%,满足了快速炼钢的需要。     

钢液中碳化钙脱砷的研究

在10kg真空感应炉中,用氩作为保护气体,以碳化钙为脱砷剂,作了钢液脱砷的试验。结果表明,在试验条件下脱砷率可达90％。脱砷率,主要取决于脱砷合成渣的用量,而与钢液原始含砷量,原始含碳及温度的关系不大。钢液中的氧对脱砷过程有阻碍作用。脱砷产物原为Ca_3As_2,不过它在高温下与空气作用要变成Ca_2As_2O_7。在脱砷的同时,熔池有增碳现象。文中还对一些热力学数据作了估算。     

碳化钙在铁水预处理中的应用

碳化钙作为铁水的脱硫剂，其脱硫效果取决于药剂的成分组成，粒度和流动性，气体载体以及使用的设备类型，脱硫的方法有喷吹，搅拌，喂丝，不同的方法脱硫效果是不同的，应用碳化钙代替部分金属脱硫能够取得良好的经济效益。     

真空碳化钙热还原法制备金属锶

对真空碳化钙热还原氧化锶制备金属锶过程进行热力学分析,获得真空条件下还原反应的自由能和还原反应临界温度。并以碳酸锶为原料,采用常压煅烧法获得了氧化锶后与碳化钙、氟化钙混合制团,进行还原反应,考察了还原温度、保温时间、制团压力、碳化钙过量系数等对锶还原率的影响。结果表明,碳化钙真空热还原制备金属锶在一定温度和真空度下能够进行,在真空度为0～100Pa、碳化钙过量20%、压片压力15MPa、还原温度1 300℃、保温时间3h的条件下,锶的平均收率可以达到72.8%,金属锶的纯度达到了98%～99%。     

碳化钙降低闪速炉渣含镍的研究

闪速熔炼是强氧化熔炼,反应塔的氧势很高,必然产生大量Fe_3O_4及NiO、Cu_2O等并进入渣中,故渣含有价金属高。针对镍闪速炉产生炉渣的过程,分析了炉渣中镍损失的途径,探索了使用碳化钙降低渣含镍的过程。碳化钙加入后炉渣含镍降低0.03个百分点(或～11%)。     

熔炼次数对M17返回料合金成分、组织和性能的影响

实验结果表明,M17铸造高温合金(%:0.16C、8.79Cr、5.79A1、4.93Ti、3.29Mo、15.20Co、0.78V、0.015B、0.073Zr、0.002S、0.001P、0.001 1O、0.001 0N)经25 kg真空感应炉返回重熔后,Si含量随重熔次数的增加而略有增加,合金中主要元素和其它杂质元素S、P、H的含量变化不大,而氧、氮略有增加;合金中初生碳化物由新合金中的草书体逐渐向返回合金块状转变,初生碳化物的遗传性堵塞合金凝固时的补缩通道,使返回料合金的疏松倾向增大,高温塑性下降较大。     

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.