磷矿中微量稀土提取技术研究进展

磷矿中伴生的微量稀土作为一种潜在的稀土资源,开展综合回收稀土的研究具有重要意义.简单介绍了磷矿中稀土含量及分布状况,综述了磷化工过程中回收稀土的最新研究进展,分别介绍了回收稀土的方法及现状,对未来磷矿中微量稀土提取技术研究方向进行了探讨.     

P204-P507在酸性硫酸盐溶液中对Nd3+和Sm3+的协同萃取

采用恒摩尔法、斜率法以及饱和容量法研究从硫酸介质中用P204(D2EHPA,用(HA)2表示)与P507(HEHEHP,用(HL)2表示)协同萃取Nd3 或Sm3 的性能与机理,并测定协萃反应的热力学平衡常数Ks.e,求得反应的焓变和熵变.结果表明,萃取反应呈现正协同效应,且协萃过程为放热反应,协萃配合物组成分别为Nd·(HA2)2-HL2和Sm·(HA2)2-HL2.因此,P204与P507混合使用可以改善硫酸介质下稀土的萃取分离效果.     

Synthesis and Characterization of Large Surface Area Yttrium Oxide by Precipitation Method

Rareearthoxides(REO)withlargesurfaceareahavehighchemicalreactionactivity ,soitisusedwidelyinthefieldofcatalysis ,SOFC ,advancedce ramicandsoon[1] .Inordertosatisfythedemandofthenewfunctionmaterials ,thepreparationmethodofspecialphysicalpropertyREcompoundneedstobedeveloped .Yttriumoxide ,especiallywithlargesur faceareaisaREOandwidelyusedintheabovefield .Industrially ,yttriumoxideusuallywaspreparedbythermaldecompositionofyttriumoxalateat 80 0～10 0 0℃for 2h .Itssurfaceareaisonly 2～ 4m2 ·…     

Preparation and Physicochemical Characterization of La_(1-x)Ce_xCoO_(3 δ) Perovskite Catalyst and Its Methane Catalytic Combustion

Methanecatalyticcombustionhasattractedmanyconcernsinrecentyearsbecauseofitshighefficiency ,lowenergycost ,lownitrogenoxidesemissions ,andlongtimestableoperationinleanburncondi tions[1～ 6 ] .MethanewhichisrichinChinaisthemaincomponentofnaturalgas .Successfulresearchandde velopmentofadvancedmethanecombustioncatalyticmaterialsisveryhelpfultoaddresstoday′sseriousen vironmentandenergyproblems .Oxidationcatalystsforexhaustedemissioncontrolaremainlynoblemetalsbecauseoftheirhighcatalyticactivity .H…     

HDEHP和HEH/EHP在硫酸介质中对Y3+的协同萃取及反萃行为研究

对HDEHP(二(2-乙基己基)磷酸或P204)和HEH/EHP(2-乙基己基膦酸单-2-乙基己基酯或P507)在硫酸介质中协同萃取Y3 的行为进行了研究.结果表明,HDEHP和HEH/EHP混合萃取剂萃取Y3 时具有明显的正协同效应,当水相平衡pH=1.2时,HDEHP和HEH/EHP混合萃取体系萃取Y3 的R(协萃系数,下同)为27.86,协萃系数随水相平衡pH的升高而增加,协萃反应式为:Y3 2H2A2(o) H2B2(o) Y(HA2)2(HB2)(o) 3H .另外,对负载Y3 的HDEHP和HEH/EHP混合萃取体系进行了反萃性能研究,结果表明.Y的反萃率随混合体系中HEH/EHP摩尔比的增加而增大;同时比较了相同酸度的HCl,HNO3及H2SO4对同一负载有机相的反萃性能,反萃能力为HCl>HNO3>H2SO4.     

焙烧氟碳铈矿硫酸浸出稀土的动力学(英文)

研究了硫酸浸出德昌稀土与天青石共伴生矿的焙烧矿过程。考查粒度、搅拌速度、硫酸浓度和温度对稀土浸出率的影响,并对稀土的浸出动力学进行分析。在选定的浸出条件下:粒径0.074～0.100mm、硫酸浓度1.5mol/L、液固比8:1、搅拌速度500r/min,稀土浸出反应受内扩散控制,表观活化能为9.977kJ/mol。     

Study on non-saponification extraction process for rare earth separation

The purpose of this study was to overcome the disadvantages of ammonia-nitrogen wastewater pollution and high cost of sodium saponification in rare earth separation process. The study focused on the non-saponification extraction technology with magnesia. The influences of the content and particle size of magnesia, reaction time, reaction temperature, and O/A on cerium extraction rate were also discussed. The results showed that the hydrogen ions of extractant were exchanged by rare earth ions when organic extractant and rare earth solution were mixed with magnesia powder, and then the exchanged hydrogen dissolved magnesia to make the acidity of the system stable. The magnesium ions were not participated in the extraction reaction. Non-saponification extraction process of rare earth had been realized. The cerium extraction rate could reach up to 99% in single stage within the optimal reaction conditions.     

H2O2氧化对铈锆复合氧化物性能的影响研究

以廉价白云石为原料所制备的碳酸氢镁溶液作为沉淀剂合成铈锆复合氧化物,研究沉淀过程中双氧水氧化稀土锆混合料液对铈锆复合氧化物性能的影响。采用XRD、BET、SEM、TPR、O2脉冲化学吸附技术等手段研究了不同氧化时间对铈锆复合氧化物的晶型、比表面积、微观形貌、氧化还原性质和储放氧能力的影响。结果表明:双氧水氧化稀土锆料液不仅可以有效提高铈锆复合氧化物的比表面和高温稳定性,抑制其发生分相,而且可以提高铈锆复合氧化物表面活性氧的数量。随着氧化时间的延长,铈锆复合氧化物的比表面积、老化性能及储氧量增加,氧化时间为30 min时达到最佳效果,其600℃焙烧新鲜比表面积为111.3 m2/g,1000℃老化比表面积为32.9 m2/g,500℃时储氧量为315μmol O2/g;继续延长氧化时间,比表面积、老化性能及储氧量变化不大。     

Study on preparation and application of novel saponification agent for organic phase of rare earths extraction

In view of the problem of ammonia-nitrogen wastewater pollution in rare earths extraction and separation, the novel saponification agent of organic phase, which is magnesium bicarbonate solution, was prepared with the natural rich and cheap dolomite as raw material through carbonation process. The behavior and purification of main impurities ions in the carbonation process as well as the application effect of the novel saponification agent in the extraction and separation was researched. The results showed that the concentration of Fe, Al, Si impurities ions was less than 5 ppm in the saponification agent through the development of effective removal technology, respectively. When the novel saponification agent was used in the extraction and separation, magnesium utilization rate was more than 95%, and rare earths extraction rate above 99.5% has achieved. Therefore, the technology could replace ammonia-water to saponify the organic phase in rare earth extraction and separation process.     

掺杂镧对Ni-Si甲烷裂解催化剂性能影响的研究

采用溶胶-凝胶法制备了Ni-Si催化剂,采用XRD,SEM,HRTEM等技术对催化剂的结构与物性进行了表征,并在微型固定床反应器中考察了甲烷的催化裂解性能,同时考察了稀土La丑对催化剂的甲烷催化裂解性能的影响.结果表明,掺杂稀土La提高了催化剂结晶度,促进了活性中心Ni的表面偏析,同时有利于产物碳物在Ni颗粒表面的扩散和径向迁移,促进均匀细长碳纳米管的形成,提高了催化剂的甲烷催化裂解活性和热稳定性,750℃时氢气生成率达90%,700℃下老化12 h后仍具有较高的催化裂解活性.