含铅渣(FeO/SiO_2=1.6,CaO/SiO_2=0.6)的挥发动力学分析

高温下含铅渣中易挥发组分的挥发对其物理化学性能测定的准确性和冶炼过程顺行都至关重要。为揭示FeO/SiO_2=1.6、CaO/SiO_2=0.6的PbO-FeO-CaO-SiO_2-ZnO含铅渣系的高温挥发特性及PbO含量变化对该体系铅渣挥发特性的影响规律,采用热重—差热分析,建立了不同PbO含量的含铅渣高温挥发动力学模型;并结合挥发后渣化学元素、XRD检测及热力学计算,揭示铅渣高温挥发规律。结果表明:高温下该铅渣体系剧烈失重主要是含铅物质挥发所致。该体系不同含铅量渣挥发趋势一致,在700～1 450℃高温段挥发最显著。含40%PbO渣的挥发率最高达33.59%,这与挥发后渣900～1 100℃水淬物相几乎检测不到Pb_2ZnSi_2O_7、Pb_2FeSi_2O_7含铅相是一致的;高铅渣挥发本征动力学分析可知,FeO/SiO_2=1.6、CaO/SiO_2=0.6的PbO-FeOCaO-SiO_2-ZnO系含铅渣的高温挥发机理函数符合Avrami-Erofeev方程,挥发过程受PbO随机成核和随后气泡生长控制,在实际冶炼过程中控制铅渣的形核长大过程可抑制高铅渣的挥发率。     

FeO/SiO2=1.6，CaO/SiO2=0.6含铅渣的挥发特性及动力学分析

高温下含铅渣中易挥发组分的挥发对其物理化学性能测定的准确性和冶炼过程顺行都至关重要。为揭示FeO/SiO2=1.6,CaO/SiO2=0.6的PbO-FeO-CaO-SiO2-ZnO含铅渣系的高温挥发特性及PbO含量变化对该体系铅渣挥发特性的影响规律,本文采用热重-差热分析,建立了不同PbO含量的含铅渣高温挥发动力学模型;并结合挥发后渣化学元素、XRD检测及热力学计算,揭示铅渣高温挥发规律。研究结果表明：高温下该铅渣体系剧烈失重的主要是由含铅物质挥发所致。该体系不同含铅量渣挥发趋势一致,在700℃~1450℃高温段其挥发最显著。含40%PbO渣的挥发率最高达33.59%,这与挥发后渣900-1100℃水淬物相几乎检测不到Pb2ZnSi2O7、Pb2FeSi2O7含铅相是一致的;高铅渣挥发本征动力学分析可知,FeO/SiO2=1.6,CaO/SiO2=0.6的PbO-FeO-CaO-SiO2-ZnO系含铅渣的高温挥发机理函数符合Avrami-Erofeev方程,挥发过程受PbO随机成核和随后气泡生长控制。因而,在实际冶炼过程中控制铅渣的形核长大过程可抑制高铅渣的挥发率。     

含锰废旧聚合物锂离子电池还原熔炼回收有价金属试验研究

以含Mn较高的废旧聚合物锂离子电池为原料, 基于CaO-Al₂O₃-SiO₂-MgO渣型直接还原熔炼工艺分离回收其中的有价金属。试验结果表明, 最佳工艺条件为: 造渣剂中CaO/SiO₂比为0.75, MgO含量5%, 造渣剂用量为电池质量的2.0倍, 焦粉用量为电池质量的0.1倍, 熔炼温度1 450 ℃, 熔炼时间15 min, 此时Co、Ni、Cu回收率分别为96.03%、96.42%、93.40%。最合适的炉渣组成为CaO/SiO₂比为0.77~1.21, Al₂O₃含量9.55%~11.92%, MgO含量4%左右。高的熔炼温度及炉渣碱度有助于Mn还原进入合金中, 但本试验条件下Mn无法充分还原, 仍主要进入炉渣中。     

B2O3对高铝低镁渣稳定性影响研究

为了明确B₂O₃对高铝低镁渣稳定性的影响,基于现场高炉渣的实际成分,通过熔体物性测定仪、Factsage软件、XPS光谱分析了B₂O₃对炉渣粘度和炉渣微观结构的影响。结果表明:随着B₂O₃含量的增加,炉渣粘度降低;当炉渣温度低于1360℃时,炉渣随着B₂O₃的增加稳定性增强;炉渣温度为1216℃, B₂O₃质量分数2.0%时,炉渣的稳定性最好。随着B₂O₃含量的增加,炉渣的液相区逐渐向MgO的区域扩大, B₂O₃的加入不仅改善了MgO含量过高引起的炉渣难熔现象,同时提高了炉渣在二元碱度波动时的稳定性。      

高炉冶金矿渣特性及其在ZTA陶瓷烧结中的作用

高炉渣是由炼铁高炉产生的一种工业废渣,其中含有CaO、Al₂O₃、SiO₂等硅酸盐成分和少量Fe₂O₃、TiO₂、ZrO₂等析晶形核剂。高炉渣在855℃热处理1 h,可形核析出1 μm左右的Ca₂Al₂SiO₇微晶,这表明高炉渣具有较高的析晶活性。向ZTA中添加质量分数为4%的高炉渣,1 550℃烧结30 min,低温下ZTA陶瓷的力学性能明显提升,抗弯强度和断裂韧性分别为650 MPa和6.03 MPa·m1/2,比相同温度下未添加高炉渣时分别提高了15%和14.2%,烧结温度降低了50℃以上。颗粒细化的高炉渣掺入ZTA陶瓷基体,烧结过程中高炉渣产生的液相促进了Al₂O₃棒晶的生长,受力过程中棒晶的拔出和裂纹的偏转有利于ZTA陶瓷力学性能的提升;高炉渣在高温下的析晶增强了ZTA陶瓷的晶界强度,进一步提高了材料的力学性能。      

MgO掺杂对高炉渣熔融调质钢渣物相组成及结构的影响

为了探明MgO掺杂对高炉渣熔融调质钢渣(混合渣)物相组成与结构的影响，采用X射线衍射仪和SEM-EDS扫描电镜对高温调质后混合渣物相组成及形貌进行了分析。结果表明，掺杂MgO能有效抑制MgFe₂O₄相和非胶凝性Ca₂Al₂SiO₇物相生成、促进MgFeAlO₄物相生成，提高混合渣熔点。MgO掺杂量2%的高温调质混合渣截面呈层状结构，内层MgFeAlO₄物相占比增加，孔洞均匀且细小；中间具有层状结构的MgFe₂O₄尖晶石包裹在MgFeAlO₄物相周围；外层Ca₂Al₂SiO₇物相孔洞均匀，致密度适中；此结构的混合渣是较好的重金属离子过滤材料。     

废旧电路板中有价金属回收试验研究

提出了一种以FeO-SiO₂-Al₂O₃-CaO渣体系为基础的废旧电路板还原熔炼工艺,从减少渣中金属损失及控制性能角度,对渣成分及结构进行调控,研究了熔剂添加量、熔炼时间、熔炼温度、炉渣组成成分对金属回收率的影响。结果表明,在熔剂添加量为原料质量30%、熔炼温度1 450 ℃、熔炼时间75 min、FeO/SiO₂比为1、渣中CaO含量8%条件下,废旧电路板中Cu、Sn回收率分别为91.98%、86.30%,贵金属Au、Ag、Pt在合金相中含量分别可达67.41 g/t、1 020.74 g/t、54.75 g/t。以该渣系为基础还原熔炼废旧电路板的工艺是可行的。     

基于共存理论的废线路板火法熔炼渣-铜平衡研究

基于炉渣结构离子分子共存理论,结合高温熔炼实验,研究了废线路板熔炼过程中铜、锡及铅在渣-铜平衡中的分配规律。以石灰为添加剂的废线路板混合料火法熔炼,其熔渣为CaO-SiO₂-Al₂O₃-FeO四元渣系。结果表明,使用熔渣结构离子分子共存理论,能较好表征该渣系组元的活度; 渣中FeO活度随着CaO含量增加先减小后增大,随着FeO含量增加而增大。渣中铜、锡及铅含量与渣中FeO活度成正比; 渣中铜、锡及铅含量随着碱度增加先降低后增加,随着FeO含量增加而增加。通过控制熔渣碱度(CaO/SiO₂)0.6~1.2、FeO含量15%~24%,可有效提高熔炼效果,使渣中铜含量低于0.7%、锡含量低于0.2%、铅含量低于0.2%。     

基于MnO-SiO2-CaO渣型的辉锑矿挥发熔炼工艺

提出以硫化锰矿作造渣剂、采用MnO-SiO₂-CaO渣型的辉锑矿挥发熔炼新工艺。试验确定的最佳工艺条件为:硫化锰矿、氧化钙和焦炭用量分别为锑精矿质量的20.01%、6.66%和4.98%,熔炼温度1 250~1 300 ℃,氧气流量0.7 L/min,熔炼时间50 min;此条件下锑锍产率5.09%,渣中Sb含量0.33%,Sb挥发率99.75%,炉渣主要由MnO、FeO、SiO₂、CaO组成,含量分别为19.11%、11.20%、34.78%和14.23%。在试验条件范围内,Mn在渣/锍两相间分配比值明显高于Fe,达到1.0。以MnS作造渣剂,采用MnO-SiO₂-CaO渣型进行辉锑矿的挥发熔炼,可望强化挥发熔池熔炼炉的顺畅运行。     

锌系统沉铁渣综合回收工艺优化研究

对侧吹烟化炉中处理锌系统沉铁渣时粉煤用量、Fe₂O₃/SiO₂比、CaO/SiO₂比、反应温度、反应时间对熔炼过程的影响进行了研究, 确定了最优工艺技术参数。结果表明, 在m_粉煤/m_渣样=1/2.8, CaO/SiO₂=0.75, Fe₂O₃/SiO₂>1, 烟化温度1 250 ℃, 烟化时间1 h条件下获得铅锌挥发率均大于96%。     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

矿用防爆轴流对旋主要通风机叶片ANSYS模态分析及应用

高效节能矿用防爆对旋主要通风机的叶片是主要通风机运行的关键部件,叶片在运行时不断受到气流的作用力,从而使叶片产生振动,当叶片振动的频率与叶片的固有频率接近时,容易产生共振从而导致叶片的断裂。一旦叶片断裂时,对主要通风机的安全运行产生致命的影响,从而导致矿山、化工等企业发生重大事故,将会产生不可估量的损失。基于有限元分析软件ANSYS,对高效节能矿用防爆轴流对旋主要通风机叶片进行模态分析及产生对应的六阶模态频率,对主要通风机叶片的运行频率、固有频率及产生的共振问题进行了原理分析,并且解决了叶片频率共振的问题,从而为主要通风机叶片结构设计提供理论依据,并对主要通风机叶片的安全运行提供保障。     

2013 NdFeB export analysis

<正>China totally exported nearly 24,000 tonsof NdFeB products during 201 3,including 18,825 tons of permanent magnet,valued USD 1.34 billion at an average price of 71.4 USD/kg;3,277 tons of NdFeB magnetic powder,valued USD 1 01 million at an average price of 30.9 USD/kg;1,334 tons of strip casting ribbon,with total export value of USD 74million at an average price of 55.3 USD/kg;and 586     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

唐口煤矿深部复杂开采工作面瓦斯分源涌出规律研究

研究工作面瓦斯涌出规律对工作面瓦斯治理有重要意义。为了得到唐口煤矿深部3号煤层复杂开采条件下工作面回采时期瓦斯涌出时空演化规律,选取6304工作面作为对象,采用实测方法研究6304工作面瓦斯涌出规律。结果表明:6304工作面瓦斯涌出量为6.534 m³/min,其中煤壁占34.27%,落煤占29.62%,采空区占36.11%;沿工作面倾向由低到高,瓦斯浓度整体为上升趋势,其中1—76号架工作面瓦斯浓度小于0.20%,76—102号架瓦斯浓度上升明显,最大为0.387%;上隅角的后部采空区是工作面的瓦斯主要涌出源,上隅角1号测点瓦斯浓度0.78%,上隅角周边3号、5号、7号、8号、9号测点瓦斯浓度平均为0.643%;周期来压时,上隅角瓦斯相对平时较高。研究为针对性的瓦斯分源监控与灾害防治提供基础。