Na_2O-CaO-Fe_2O_3系物相关系及固相反应动力学

一、前言烧结法熟料中 Na_2O、CaO、Al_2O_3、Fe_2O_3、SiO_2的总和大于95%。组成此五元系的三元系,大部分都已研究过,但还有 Na_2O-CaO-Fe_2O_3系尚未见到研究资料。我国烧结法技术成就之一是熟料采用低碱、低石灰非饱和配料,使熟料的 Na_2O 标准溶出率大于Al_2O_3的溶出率。汪仲钧、阿拉盖良等都指出熟料中有四钙铝酸固溶体存在,这是引起 Al_2O_3损失的原因之一,但这些结果还未能说明四钙铁铝酸     

粉煤灰提取氧化铝中生料配料对熟料性能影响

正采用了三种粉煤灰生料配方制备的熟料进行溶出实验,实验结果表明:熟料溶出率都在86%以上,其中生料配比碱比[N/R]=0.95、钙比[C/S]=2.00的熟料Al2O3溶出性能接近标准溶出率。对快速冷却的熟料XRD分析,发现有β-2CaO·SiO2和γ-2CaO·SiO2两种晶型。从粉煤灰中提取氧化铝,对减轻粉煤灰污染、扩大粉煤灰利用途径具有非常重要的意义[1]。近年来,开展了从粉煤灰中,特别是高铝粉煤灰提取氧化铝科技攻关和产业化探索,初步形成了以下几种     

碱法从粉煤灰中提取铝硅的新探索

碱石灰烧结法从粉煤灰中提取氧化铝的最佳工艺条件是:生料配比[N/R]为0.95,[C/S]为2.0,烧结温度1250℃,烧结时间30min;熟料溶出温度80℃,时间30min,调整液αK为1.60±0.05,氧化铝浓度10g/L,碳酸钠浓度12g/L;采用三段脱硅,精液硅量指数>600,精液分解温度90℃,种子加量20g/L。证明用粉煤灰碱-石灰烧结法生产氧化铝技术上可行,同时,提出了碱石灰烧结法生产粗氢铝后再重溶及低浓度处理粉煤灰联合生产水玻璃的工业应用改进途径。     

铝土矿低钙烧结熟料的浸出性能研究

研究了从铝土矿低钙石灰烧结熟料中浸出氧化铝,考察了液固体积质量比、碳碱质量浓度、苛性碱质量浓度、浸出温度、浸出时间对氧化铝浸出率的影响。结果表明,铝土矿低钙烧结熟料具有较好的浸出性能,最佳条件下,氧化铝浸出率可达87.3%。     

粉煤灰提取氧化铝工艺能耗分析

介绍了粉煤灰预脱硅-碱石灰烧结法、盐酸浸取法和硫酸焙烧法提取氧化铝的工艺方法,计算和分析了以上三种工艺的理论能耗。结果表明,三种工艺中预脱硅—碱石灰烧结法能耗最高,为1 707kgce(每吨Al_2O_3,下同),其中烧结工序就占总能耗的53.67%;盐酸浸取法与硫酸焙烧法能耗较低,分别为1 396kgce和1 476kgce,比预脱硅—碱石灰烧结法分别降低了18.3%和13.5%。盐酸浸取法中42.57%的能耗集中在AlCl_3·6H_2O晶体热解工序,而Al_2(SO_4)_3·18H_2O晶体脱水能耗占硫酸焙烧法总能耗的51.38%。     

电炉轴承钢中的氧化物夹杂

文章对GCr_(15)的氧化物夹杂进行分析。采用矽钙合金脱氧,观察到塑性、链状球状三种氧化物夹杂,其中塑性夹杂是含锰的矽酸盐,链状及球状夹杂基本组成是含钙的矽酸盐。采用铝脱氧,主要观察到链状及球状氧化物夹杂,夹杂物由钙、镁的铝(矽)酸盐组成。链状夹杂有CaO·2Al_zO_3、CaO·Al_2O_3、MgO·Al_2O_3,Al_2O_3—CaO—MgO系,Al_2O_3—CaO—SiO_2系。球状夹杂有3CaO·Al_2O_3、12CaO·7Al_2O_3。上述各种夹杂物中普遍含镁、铁。用铝脱氧,随着脱氧剂铝量的增加,夹杂物中铝含量常常相应地增多。对氧化物夹杂的主要来源,形态进行分析,提出看法,以便为改善电炉钢的洁净度提供一些参考。     

粉煤灰提取氧化铝工艺能耗分析

介绍了粉煤灰预脱硅-碱石灰烧结法、盐酸浸取法和硫酸焙烧法提取氧化铝的工艺方法,计算和分析了以上三种工艺的理论能耗。结果表明,三种工艺中预脱硅—碱石灰烧结法能耗最高,为1 707kgce(每吨Al_2O_3,下同),其中烧结工序就占总能耗的53.67%;盐酸浸取法与硫酸焙烧法能耗较低,分别为1 396kgce和1 476kgce,比预脱硅—碱石灰烧结法分别降低了18.3%和13.5%。盐酸浸取法中42.57%的能耗集中在AlCl_3·6H_2O晶体热解工序,而Al_2(SO_4)_3·18H_2O晶体脱水能耗占硫酸焙烧法总能耗的51.38%。     

粉煤灰生料配比对熟料烧成温度及溶出性能的影响研究

本文以高铝粉煤灰预脱硅后脱硅灰为原料,在固定生料浆碱比0.95~1的前提下,研究了不同钙比、铁铝比对熟料烧成温度范围及溶出性能的影响。试验结果表明:高钙配比相对于低钙配比氧化铝溶出率提高1.5%~2.3%,氧化钠溶出率提高0.22%~1.5%;生料铁铝比由0.032提高至0.05可降低熟料烧成温度20℃,可扩宽熟料烧成温度范围10℃。     

烧结助剂中CaO质量分数及烧结温度对氧化铝基微波陶瓷性能的影响

选用CaO–SiO_2–TiO_2作为氧化铝陶瓷的烧结助剂,在空气气氛下经过常压烧结制备Al_2O_3陶瓷。研究了烧结助剂中CaO质量分数以及烧结温度对Al_2O_3基微波陶瓷的相组成、微观结构和介电性能的影响。结果表明:添加含CaO烧结助剂的Al_2O_3陶瓷中,出现了CaAl_(12)O_(19)第二相,相含量随着CaO质量分数的增加而增加;随着烧结助剂中CaO质量分数的增加,Al_2O_3陶瓷试样介电常数增大,品质因数先升高后降低。随着烧结温度的升高,Al_2O_3陶瓷相对密度和品质因数先升高后降低,介电常数和谐振频率温度系数增大。当烧结温度为1450℃、烧结助剂中CaO质量分数为0.4%时,烧结体的相对密度达到最大值98.61%,介电常数为9.88,品质因数值为21957GHz,谐振频率温度系数为-21.353×10~(-6)/℃。     

12 CaO·7 Al2 O3晶体结构及其氧化铝浸出性能

使用分析纯试剂配料,在1350℃保温1 h的条件下合成了A/S=5(Al2O3与Si O2质量比)的铝酸钙熟料.研究了钙铝比C/A(除去与Si O2结合的Ca O后Ca O与Al2O3的摩尔比)对熟料中12Ca O·7Al2O3晶体结构及其氧化铝浸出性能的影响,并通过X射线衍射和X射线荧光等分析手段对其作用机理进行了探讨.结果表明:由于12Ca O·7Al2O3量的增加,C/A=1.0~1.4时,石灰烧结法熟料溶出率随着C/A的提高而提高;在C/A=1.4时,熟料溶出率最高可达93.30%,此时Ca O的缺失形成了有缺陷的12Ca O·7Al2O3,且其中Ca O的物质的量小于11.3 mol;钙铝比提高到1.7时熟料溶出率又出现了下降趋势,这是由于Ca O的饱和导致12Ca O·7Al2O3晶体择优生长取向发生变化,由(211)面开始向(420)晶面转变.     

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.