离子吸附型稀土矿的除铝研究

在我国南方离子吸附型稀土生产过程中,铝的含量不仅影响稀土氧化物产品的质量,而且还增加原材料的消耗。本文探索了一套南方稀土矿生产中降低铝含量的方法,并分析对比了应用该工艺前后的结果,试验取得了满意的效果。     

The influence of temperature on rare earth flotation with naphthyl hydroxamic acid

The influence of temperature on the complex process of Bayan Obo rare earth (RE) ore flotation with a collector of naphthyl hydroxamic acid (LF8#) was investigated. Industrial test data shows that the grade and recovery of RE increase with the temperature. However, the proportion of bastnaesite in the bulk concentrate increases as the RE grade improves. Adsorption mechanism of LF8# on the surfaces of bastnaesite and monazite were confirmed via zeta potential, UV/Vis Spectrophotometer (UV/Vis), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy analyses (XPS). Although the results indicate that the total amount of the LF8# adsorption on the surface of bastnaesite and monazite decreases with increasing the temperature, the amount of stable adsorbed predominance of characteristic bonds (C(O)N) from LF8# uptake on bastnaesite surfaces increases significantly at high temperatures. This conclusion indicates that the adsorption stability increases with increasing the temperature. For monazite, the amount of characteristic elements C and N in LF8# does not increase as the temperature increases on the mineral surface, but the proportion of characteristic bonds increases, which shows that the adsorption stability of LF8# on the surface of monazite also increases, but it is not as significant as bastnaesite, which may be one of the reasons that the floatability of bastnaesite is better than those of monazite. Pulp dispersion results show that the temperature improve the dispersions of both the gangue and RE minerals. This improved the flotation selectivity so that it favored RE minerals. The calculated bubble size distribution confirms that higher temperatures generate smaller bubbles, thereby increasing the bubble-particle collision probability and the recovery of RE minerals.     

伯氨树脂对稀土矿酸浸出液中钍的吸附研究

合成了一种伯胺树脂,对钍具有很好的选择性,当钍浓度为125mg/L时,吸附钍的分配比达到2.48×103。与铁和铈的分离系数分别为1.29×104和9.7×104,吸附钍的最佳[SO42-]=1.0mol/L,[H+]=0.1mol/L,接触时间5min。对钍的去除率大于99%,处理液中钍浓度<0.001mg/L。     

Adsorption of rare earth elements on organic matter in coal

The occurrence modes of rare earth elements(lanthanide and yttrium,abbreviated as REY) in coal are impo rtant both for coal geochemistry studies and the application potential of REY as a by-product of coalbased resources.In this study,the adsorption behaviors of REY on organic matter in coal were investigated by leaching tests using REY solution and ultra-low ash coal samples.On this basis,the adsorption mechanism of REY on organic matter in coal was also studied by molecular simulation calculat...     

Adsorption behavior of rare earth elements using polyethyleneglycol (phosphomolybdate and tungstate) heteropolyacid sorbents in nitric solution

A new type of crystalline sorbent was prepared by the reaction of polyethyleneglycol (PEG) with phosphomolybdic (PMo) and phosphotungstic (PW) heteropolyacids. The morphology of the obtained sorbents was studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It has been shown that a complexing reaction occurs between PEG and the heteropolyacids. By using these sorbents, the adsorption behaviors of rare earth elements in nitric solution were studied. The effects of temperature, contact time, nitric acid and initial metal ion concentration on the adsorption were investigated. In 0.1–5.0 mol L^− 1HNO₃, the adsorption percentage decreases with the increase of acid concentration. H,PEG400,PW and H,PEG400,PMo exhibited a different selectivity for rare earth metals, with H,PEG400,PW adsorbing in the order of La³⁺ > Y³⁺ > Pr³⁺ > Gd³⁺ > Sm³⁺, and H,PEG400,PMo in the order of Y³⁺ > La³⁺ > Pr³⁺ > Gd³⁺ > Sm³⁺. The experimental maximum adsorption capacities of the sorbents are in the range of 90–225 mg g^− 1 for Y³⁺, La³⁺, Pr³⁺, Sm³⁺ and Gd³⁺. In all cases, the maximum adsorption capacities of H,PEG400,PW are near to those of H,PEG400,PMo. The equilibrium data were evaluated according to the Freundlich and Langmuir isotherms and the Langmuir equation gave a better fit and modeled the adsorption well.     

自增韧氮化硅及其陶瓷轧辊制备技术的研究

介绍近年来氮化硅陶瓷的研究进展,分析、介绍采用自增韧氮化硅材料制备陶瓷轧辊的技术和应用前景。     

黑色风化物的物理化学性质及稀土配分研究

某稀土矿产生的黑色风化物，是一种稀土以胶态相赋存的新稀土资源。黑色风化物主要由锰、铁，稀土和铅组成，形成锰铁氧化物非晶质的高聚合度无机高分子。黑色风化物强烈地选择铈族轻稀土，与矿区产的矿石和氟碳铈矿稀土配分相近，但黑色风化物含中重稀土最高，矿石次之，氟碳铈矿最低。     

金属钕及氧化钕中稀土杂质光谱测定

在色散０．２５ｍｍ／ｍｍ光栅光谱仪上,以控制气氛直流电弧粉末地测定了金属钕及氧化钕中氧化镧、氧化铈、氧化镨、氧化钐、氧化钆、氧化镝和氧化钇。采用正交设计实验,确定了测定条件。测定的下限对氧化铈、氧化镨为０．０５％,氧化镧、氧化钐、氧化钆、氧化镝和氧化钇为０．０３％,相对标准偏差为６％￣１８％。     

工艺参数对熔配法制备Al-10Ce中间合金的影响

用熔配法制备了Al-10Ce中间合金,采用X射线衍射相分析(XRD)等技术对Al-10Ce中间合金的相组成进行了分析,试验结果表明:Al-10Ce中间合金由Al、Ce、Al4Ce三相组成。且通过试验从熔体温度、溶解时间、搅拌方式等三方面分析了用熔配法制备Al-10%Ce中间合金的工艺参数,确证了参数选择的可行性和合理性。     

Report on Rare Earth Market Evolution and Involvement of Rhone－Poulenc in the Market

ＲｅｐｏｒｔｏｎＲａｒｅＥａｒｔｈＭａｒｋｅｔＥｖｏｌｕｔｉｏｎａｎｄＩｎｖｏｌｖｅｍｅｎｔｏｆＲｈｏｎｅ－ＰｏｕｌｅｎｃｉｎｔｈｅＭａｒｋｅｔＭａｔｔｈｅｗｓＪＤ；ＶａｎｄｅｒｓｔｒｉｃｈｔＪＰ（Ｒｈｏｎｅ－ＰｏｕｌｅｎｃＲａｒｅＥａｒｔｈｓａｎｄ...     

Effect of Rare Earths on Precipitation Kinetics of Niobium Carbide in Microalloyed Steel

ＥｆｅｃｔｏｆＲａｒｅＥａｒｔｈｓｏｎＰｒｅｃｉｐｉｔａｔｉｏｎＫｉｎｅｔｉｃｓｏｆＮｉｏｂｉｕｍＣａｒｂｉｄｅｉｎＭｉｃｒｏａｌｏｙｅｄＳｔｅｌＹｅＷｅｎ（叶文），ＬｉｕＹｏｎｇｈｕａ（刘勇华），ＬｉｎＱｉｎ（林勤），ＣｈｅｎＮｉｎｇ（陈宁）（Ｄｅ...     

Rare earth oxides and their supported noble metals in application of environmental catalysis

Volatile organic compounds(VOCs),methane,carbon monoxide,soot,automotive exhaust,and nitrogen oxides are harmful to the atmosphere and human health.It is urgent to strictly control their emissions.Heterogeneous catalysis is an effective pathway for the removal of these pollutants,and the critical issue is the development of novel and high-performance catalysts.In this review,we briefly summarize the preparation methods,physicochemical properties,catalytic activities,and related reaction mechanis...     

The Characteristics of Adsorption and Desorption of Rare Earth Elements by the Main Types of Soils of China

The adsorption-desorption behavior of the mixed rare earth elements(RE)on the main types ofsoils of China,kaolinite and synthetic oxides was studied.The isothermal adsorption of RE was fitted toLangmuir.Freundlich and Temkin equations.The main factors determining the RE adsorption capacity ofthe soils are the type of clay mineral and the content of amorphous iron oxide in the soils.The above two fac-tors and the pH of soil determine the RE adsorption ability of the soils.The soil and synthetic iron,manga-nese oxides strongly adsorb RE specifically.     

Genesis of nanocrystalline Ho2O3 via thermal decomposition of holmium acetate: Structure evolution and electrical conductivity properties

This study focuses on the preparation of nanostructured holmium oxide via the decomposition of holmium acetate precursor utilizing the non-isothermal strategy. Thermogravimetric analysis(TGA) was used to follow up the various thermal events involved in the decomposition process. Dehydration completes approximately at 150℃, which is followed by the decomposition of the anhydrous acetate leading to the formation of holmium oxide. Based on the TGA results the acetate precursor was heated non-isothermally at the temperature range of 150 e700℃. The obtained solids were characterized using powder X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Fourier transform infrared spectroscopy(FT-IR), field-emission scanning electron microscopy(FE-SEM) and transmission electron microscopy(TEM). It is found that nanocrystalline Ho_2 O_3 starts to form at 500℃ and presents the only phase detected at the 500 e700℃ range. The electrical conductivity of the solids that form at the temperature range of 300 e700℃ was investigated. The obtained values were correlated with the observed structural modifications accompanying the heat treatment. The electrical conductivity of the Ho_2 O_3 samples prepared at 500, 600 and 700℃ reaches the values of 1.92 × 10~(-7), 1.61 × 10~(-7) and 8.33 × 10~(-8) Ω~(-1)cm~(-1) at a measuring temperature of 500℃, respectively. These values are potentially advantageous for high-resistivity devices.     

Effects of iron and temperature on solubility of light rare earth sulfates in multicomponent system of Fe2(SO4)3-H3PO4-H2SO4 synthetic solution

Numerous light rare earth elements (LREE) minerals containing Fe and P were processed by sulfuric acid roasting method, and the leaching solution mainly comprises LREE sulfate, Fe₂(SO₄)₃, H₃PO₄, and H₂SO₄, however, the solubility data of LREE sulfates in this system is few. This work studies the solubility of LREE sulfates in independent LREE sulfate system RE₂(SO₄)₃-Fe₂(SO₄)₃-H₃PO₄-H₂SO₄ (RE = La, Ce, Pr or Nd) and mixed LREE sulfates system (La,Ce,Pr,Nd)₂(SO₄)₃-Fe₂(SO₄)₃-H₃PO₄-H₂SO₄ at different temperature (25–65 °C) and concentrations of Fe₂(SO₄)₃ (Fe₂O₃, 0–50.13 g/L), H₂SO₄ (0.5 mol/L), and H₃PO₄ (P₂O₅, 20.34 g/L) based on the industrial operating condition at low liquid and solid ratio 2:1. The solubility of each LREE sulfate in the independent system (La₂O₃, 12.25–20.88 g/L; CeO₂, 41.93–62.35 g/L; Pr₆O₁₁, 37.34–56.69 g/L; Nd₂O₃, 26.60–37.63 g/L) is much higher than that of the mixed system (La₂O₃, 6.95–11.03 g/L; CeO₂, 10.63–21.51 g/L; Pr₆O₁₁, 11.56–20.36 g/L; Nd₂O₃, 12.36–19.79 g/L) under the same other conditions. The results also indicate that, in the two systems, both Fe and the temperature have negative effects on the solubility of LREE sulfates. That may occur due to the complication reactions between the complexes of RESO₄⁺ and Fe(SO₄)₂^–. However, the influence degree of temperature and iron concentration on the LREE sulfates solubility varies in the two systems and among different LREE species. This research is of theoretical significance for optimizing the conditions of the sulfuric acid process for recovering the LREE from the mixed LREE bearing minerals as well as the single LREE containing secondary rare earth scraps.     

Comparative studies on promotional effect of Pr6O11,Nd2O3 and Sm2O3 on Ni-SiO2 for pressurized carbon dioxide reforming of methane

The 7 wt% rare earth metal oxide promoted Ni-SiO₂ catalysts of Ni-7Pr₆O₁₁-SiO₂,Ni-7Nd₂O₃-SiO₂,and Ni-7Sm₂O₃-SiO₂ were prepared by the complex-decomposition method,and were comparatively evaluated for pressurized carbon dioxide reforming of methane(CRM) under severe conditions of 750℃,1.0 MPa,CH₄/CO₂=1,and gas hourly space velocity of 53200 mL/(g·h).The addition of r...     

Effects of lanthanum on hot deformation behaviour of Mn-Cr-Mo bainitic rail steel

Effects of lanthanum(La) as micro-alloying element on the hot deformation behaviour of the high strength Mn-Cr-Mo bainitic rail steel were investigated under a range of deformation conditions. The results indicate that La increases the flow stress by 10-30 MPa through strengthening nanoscale strain induced precipitation(SIP) θ-(Fe,La)3 C during hot deformation. The hot deformation activation energy increases by 10-40 kJ/mol due to the "Zener effect" of SIP and the dynamic recrystallization(DRX) is retarded due to the competitive behaviour between SIP and DRX. Bainite plates in the DRX domain can be refined by adding La, resulting in the improvement of hot workability. The DRX domain with peak power dissipation efficiency of 52% is determined to be the optimal processing region for Mn-Cr-Mo-La bainitic rail steel.     

Studies on Rare Earth Complexes with Ethylene-1,2-Dioxydiacetic Acid

ＳｔｕｄｉｅｓｏｎＲａｒｅＥａｒｔｈＣｏｍｐｌｅｘｅｓｗｉｔｈＥｔｈｙｌｅｎｅ－１，２－ＤｉｏｘｙｄｉａｃｅｔｉｃＡｃｉｄＸｕｅＷｅｎ－Ｍｅｉ；（薛文梅）；ＣｕｉＹｕ－Ｘｉｎ；（崔育新）；ＹａｎｇＲｕ－Ｄｏｎｇ；（杨汝栋）（ＤｅｐａｒｔｍｅｎｔｏｆＣ...     

Mineralogical and Petrological Studies on Carbonatite Dykes in Bayan Ebo，Nei Mongol，China and Their Implication to Rare Earth Mineralization

ＭｉｎｅｒａｌｏｇｉｃａｌａｎｄＰｅｔｒｏｌｏｇｉｃａｌＳｔｕｄｉｅｓｏｎＣａｒｂｏｎａｔｉｔｅＤｙｋｅｓｉｎＢａｙａｎＥｂｏ，ＮｅｉＭｏｎｇｏｌ，ＣｈｉｎａａｎｄＴｈｅｉｒＩｍｐｌｉｃａｔｉｏｎｔｏＲａｒｅＥａｒｔｈＭｉｎｅｒａｌｉｚａｔｉｏｎＺｈ...     

Effect of rare earth on the performance of Ru/MgAl-LDO catalysts for ammonia synthesis

A series of MgAl-layered double oxides (LDO) doped with different rare-earth elements (Y, La, and Ce) were synthesized by the calcination of Mg–Al layered double hydroxides, and Ru, which were used to prepare ammonia synthesis catalysts. The as-obtained oxides and catalysts were characterized by XRD, TEM, TPD, TPR and XPS to understand their catalytic performances in ammonia synthesis. The H₂-TPR and HRTEM studies reveal that Ru/Y-LDO catalyst possesses more active Ru metal and small particle size. The XPS demonstrates that the electronic interaction between Y and Ru metals is stronger, which can be tentatively explained by most of Y inserted into the hydrotalcites structure. CO₂-TPD demonstrates that Ru/Y-LDO catalyst shows stronger basic site densities than catalysts doped with Ce and La. Higher activity of the Ru/Y-LDO catalyst can be attributed to smaller particle size, more active metal (Ru) and strong Ru–support interaction.