响应曲面法优化赤铁矿絮凝体浮选行为研究

采用淀粉为絮凝剂对平均粒径为8 μm的赤铁矿纯矿物进行絮凝,形成平均粒径36.17 μm、絮凝体密度2.89g/cm3、絮凝体孔隙率49.12％、分形维数为1.90的絮凝体.根据Box-Behnken实验设计原理,采用响应曲面法建立pH值、捕收剂油酸钠用量、搅拌转速及三者之间交互作用对赤铁矿絮凝体回收率影响的多元回归方程,对实验结果进行了 ANOVA分析.在矿浆pH为7.76,油酸钠用量为132.22 mg/L,搅拌转速为1844 r/min,此条件下模型预测絮凝体回收率达到93.65％.通过赤铁矿浮选条件探究,得出其对絮凝体浮选的作用规律,为指导实践生产应用提供理论支撑.     

不同粒度对赤铁矿可浮性的影响

通过赤铁矿纯矿物浮选试验,研究了不同粒度对赤铁矿可浮性的影响,测定了不同粒度对捕收剂YSB的吸附量,并对不同粒径赤铁矿颗粒进行了矿粒-气泡的碰撞概率与上浮概率计算。研究结果表明,4种不同粒度赤铁矿均在转速为1900r/min,矿浆浓度为20%,pH=6~7,捕收剂YSB用量为25mg/L条件下浮选回收率达到最大值,但平均粒度10.05μm粒度的回收率要低于其它3个粗粒度。同时当颗粒的粒径降低为15μm时,矿粒-气泡的碰撞概率仅为0.35%,上浮概率为1.38%,导致浮选回收率大幅度降低。     

不同搅拌条件对微细粒赤铁矿絮凝粒径的影响研究

通过单矿物絮凝试验,考察了搅拌速度、搅拌时间、轴向距离对赤铁矿絮凝行为的影响。结果表明,在搅拌速度300r/min,搅拌时间3min,轴向距离为2.5cm时,絮凝体平均粒径为35.38μm,这为后续的浮选提供了基础,同时对于浮选装置的优化提供了依据。对搅拌速度、搅拌时间、轴向距离三个因素进行正交试验,结果表明,搅拌速度对絮凝体粒径的影响最大,搅拌时间影响最小,并对所得絮凝体的特性进行了研究。     

不同类型表面活性剂乳化煤油对低阶煤浮选的影响研究

选取阴离子表面活性剂十二烷基硫酸钠(SDS)、阳离子表面活性剂十二烷基三甲基溴化铵(DTAB)、非离子表面活性剂Tween-80三种不同类型的表面活性剂分别与煤油制成乳化煤油捕收剂，对低阶煤进行浮选试验，对比乳化前后捕收剂的浮选效果。采用激光粒度仪、接触角和傅里叶红外光谱分析仪(FTIR)分析了乳化煤油的作用机理。结果表明：在捕收剂用量为6000 g/t,单独采用煤油作捕收剂时，精煤可燃体回收率为60.07%,浮选完善指标为30.44%。采用乳化煤油的浮选效果均优于煤油，当采用Tween-80乳化煤油作捕收剂时，精煤可燃体回收率达到最大值，为88.05%,浮选完善指标31.21%。粒度分析表明，乳化作用可降低油滴粒径，煤油在水中分散的平均粒径为167μm, Tween-80乳化煤油的平均粒径为1.19μm, SDS乳化煤油的平均粒径为0.152μm, DTAB乳化煤油的平均粒径为1.52μm。结合浮选结果可知，乳化煤油油滴平均粒径1.19μm且小于3.77μm油滴占90%时，精煤可燃体回收率和浮选完善指标最高。FTIR和接触角结果表明，捕收剂有效吸附在低阶煤表面并降低含氧官能团对浮选的...     

搅拌流场对微细粒赤铁矿絮凝体特性的影响

微细粒矿物因为粒度较细使用常规的选别方法很难达到预期的分选效果,尤其是赤铁矿,赤铁矿由于其堪布粒度细,成分复杂成为世界公认的难选矿物之一。絮凝是解决矿物选别粒度的最直接的方法。本文以河北某铁选矿厂重选精矿为原矿样制取超纯赤铁矿,并对超纯赤铁矿样进行化学多元素分析,由结果可知赤铁矿纯矿物的的全铁品位为68.94%,纯度可达98.49%。以制取的超纯赤铁矿为研究对象,研究了不同搅拌槽形状、搅拌速度、作用时间以及轴向距离对絮凝体粒径和分形维数的影响,并通过计算絮凝体的强度和孔隙率说明絮凝体的特性。结果表明:搅拌槽形状为方形时,在搅拌转速为900 r/min,作用时间为3.5 min,轴向距离为2 cm的条件下能够得到絮凝体的粒径为35.44μm,分形维数为1.6589,絮凝体强度为1118.84 Pa/mm~2,孔隙率为51.70%。所得絮凝体密实程度较高,强度较好,为以后絮凝工艺的更深入研究提供了有力的依据。     

用油酸钠对赤铁矿进行剪切絮凝和浮选的研究(一)

对采用油酸钠作为选择性絮凝剂使超细(<10μm)的赤铁矿与石英分离进行了研究。影响赤铁矿絮凝物粒度的主要因素是油酸浓度、pH值、剪切速度和搅拌时间。只有当溶液中油酸的溶解度过饱和时,才能产生絮凝作用。如果在矿物颗粒周围产生油酸液滴,就会发现絮凝速度和絮凝物粒度增加。产生的赤铁矿絮凝物在300/s～2200/s的剪切速度范围内有抗破裂作用。其强度归因于碳氢链连接和疏水性的相互作用产生的引力。用油酸钠形成的疏水性絮凝物用浮选法很容易回收。含Fe15%的赤铁矿和石英混合给矿经粗选回收率达到94%,精矿品位为46%Fe。超细矿物在浮选之前进行剪切絮凝,为显著提高矿物回收率,提供了一种可能的方法。     

搅拌槽内流体特征对絮凝特性的影响

在两种不同形状的搅拌槽中研究流体特征对微细粒赤铁矿絮凝特性的影响。试验结果表明:方形槽中,在转速1 000 r/min、作用时间4 min、轴向距离为2 cm的条件下能够形成粒径35.37μm、分形维数1.628 9、沉降速度1.132 6 cm/s、密度4.62 g/cm~3、孔隙率51.83%的絮凝体;圆形槽中,在转速1 100 r/min、作用时间4 min、轴向距离1.5 cm的条件下能够形成粒径35.67μm、分形维数1.599 4、沉降速度1.063 7cm/s、密度4.51 g/cm~3、孔隙率54.38%的絮凝体。两者相比,方形槽中较小转速下就可获得更密实的絮凝体。     

基于图像处理技术的赤铁矿絮凝体-气泡矿化过程研究

为了探究赤铁矿絮凝体-气泡的矿化过程,在自制的观察装置中,以静止气泡为研究对象,通过高速 相机记录赤铁矿絮凝体在气泡表面的运动状态,得到赤铁矿絮凝体-气泡矿化过程。结果表明：气泡直径不变的条 件下,赤铁矿絮凝体粒径为 39.65 μm 时,絮凝体最先滑动至最大横向位置和最小纵向位置,瞬时滑动速度变化范围 小;赤铁矿絮凝体粒径不变的条件下,气泡直径为 636.16 μm 时,絮凝体滑动至最大横向位置和最小纵向位置的时 间最长,瞬时滑动速度变化范围大;絮凝体粒径和气泡直径不变的条件下,碰撞角度大于 60°时,絮凝体易从气泡表 面脱附。利用高速摄像仪探究并分析了絮凝体-气泡矿化规律,为指导絮凝浮选实践应用提供理论支撑。     

某微细粒赤铁矿纯矿物的絮凝试验研究

絮凝团聚可增大微细粒矿物的尺寸,有利于后续选别。以平均粒径为10.13μm的司家营赤铁矿纯矿物为试验矿样,分别考察絮凝剂种类及用量、矿浆p H、搅拌制度等因素对絮团粒度和沉降率的影响。试验结果表明:以支链淀粉为絮凝剂、用量为120 mg/L,在矿浆p H值为6、搅拌速度为1 000 r/min、搅拌时间3 min的最佳条件下,赤铁矿纯矿物可絮团至35μm左右,沉降率高于97%,指标较好,可为赤铁矿絮凝分选提供参考依据。     

铁矿石浮选过程中矿物的交互影响及机理研究

复杂矿石浮选体系中矿物间会产生交互影响,研究了在油酸钠浮选体系中,不同粒级的磁铁矿、赤铁矿和石英的交互影响,并讨论了其机理。结果表明:-45+18μm粒级磁铁矿会显著降低赤铁矿的回收率,主要是因为微细粒级矿物消耗了大量捕收剂;-18μm粒级磁铁矿能够大幅度降低石英的回收率,其原因是-18μm粒级磁铁矿在石英粗颗粒表面发生了罩盖;不同粒级磁铁矿,对赤铁矿和石英混合矿浮选会有不同的影响,由于-106+18μm粒级磁铁矿被抑制进入浮选精矿,使浮选精矿铁品位略有提高,-18μm粒级磁铁矿降低浮选精矿铁品位与矿物罩盖有关。     

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     

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     

2014 second batch of rare earth quota released

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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