锂辉石浸出液提锂除杂规律研究

碳酸锂是一种基础锂盐, 不仅广泛应用于传统化工行业, 也是生产锂电池的重要原料, 近年来锂电产业蓬勃发展, 极大推动了原料碳酸锂的提取与制备研究。为了提取锂辉石中的锂来制备碳酸锂, 利用沉淀溶解-平衡理论分析锂浸出液的除杂规律。对锂辉石进行转型焙烧、酸化焙烧、浸取, 锂辉石中98%左右的锂可进入液相, 得到锂浸出液, 然后根据溶解平衡理论确定3步除杂净化条件：1）中和pH至6.5除大部分Al ³⁺和Fe ³⁺;2）加入氧化剂将Fe ²⁺氧化成Fe ³⁺, 调 pH 至8.0除Fe ³⁺;3）调pH至10.0, 加入理论量碳酸钠（以液相Ca ²⁺计）, 最终Al ³⁺、Fe ³⁺、Mg ²⁺ 等浓度低于10 ^-6 mol/L, Ca ²⁺质量分数约为2×10 ^-5。     

Ultrafiltration recovery of alginate: Membrane fouling mitigation by multivalent metal ions and properties of recycled materials

Recovery of alginate extracted from aerobic granular sludge (AGS) has given rise to a novel research direction. However, these extracted alginate solutions have a water content of nearly 100%. Alternately, ultrafiltration (UF) is generally used for concentration of polymers. Furthermore, the introduction of multivalent metal ions into alginate may provide a promising method for the development of novel nanomaterials. In this study, membrane fouling mitigation by multivalent metal ions, both individually and in combination, and properties of recycled materials were investigated for UF recovery of sodium alginate (SA). The filtration resistance showed a significantly negative correlation with the concentration of metal ions, arranged in the order of Mg²⁺ < Ca²⁺ < Fe³⁺ < Al³⁺ (filtration resistance mitigation), and the moisture content of recycled filter cake showed a marked decrease. For Ca²⁺, Mg²⁺, Fe³⁺, and Ca²⁺+Fe³⁺, the filtration resistances were almost the same when the total charge concentration was less than 5 mmol·L^-1. However, when the total charge concentration was greater than 5 mmol·L^-1, membrane fouling mitigation increased significantly in the presence of Ca²⁺ or Fe³⁺ and remained constant for Mg²⁺ with the increase of total charge concentration. The filtration resistance mitigation was arranged in the order of Fe³⁺ > Fe³⁺ + Ca²⁺ > Ca²⁺ > Mg²⁺. Three mechanisms were proposed in the presence of Fe³⁺, such as the decrease of SA concentration, change in pH, and production of hydroxide iron colloids from hydrolysis. The properties of recycled materials (filter cake) were investigated via optical microscope observation, dynamic light scattering, Fourier transform infrared, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. The results provide further insight into UF recoveries of alginate extracted from AGS.     

Simultaneous removal of total oxidizable carbon,phosphate and various metallic ions from H2O2 solution with amino-functionalized zirconia as adsorbents

Amino-functionalized zirconia was synthesized by the co-condensation method using zirconium butanol and 3-aminopropyltriethoxy silane for the simultaneous removal of various impurities from aqueous 30% H₂O₂ solution. The results of Fourier transform infrared (FTIR) and Zeta potential showed that the content of N in amino-functionalized zirconia increased with the added amount of 3-aminopropyltriethoxy silane. Accordingly, the removal efficiency of total oxidizable carbon, phosphate and metallic ions from the H₂O₂ solution increased. The adsorbent with an N content of 1.62% exhibited superior adsorption performance. The removal efficiency of 82.7% for total oxidizable carbon, 34.2% for phosphate, 87.1% for Fe³⁺, 83.2% for Al³⁺, 55.1% for Ca²⁺ and 66.6% for Mg²⁺, with a total adsorption capacity of 119.6 mg·g^–1, could be achieved. The studies conducted using simulated solutions showed that the adsorption process of phosphate on amino-functionalized zirconia is endothermic and spontaneous, and the behaviors could be well described by the pseudo-second-order model and Langmuir model with a maximum adsorption capacity of 186.7 mg·g^–1. The characterizations of the spent adsorbents by Zeta potential, FTIR and X-ray photoelectron spectroscopy revealed that the adsorption mechanism of phosphate is predominantly electrostatic attraction by the protonated functional groups and complementary ligand exchange with zirconium hydroxyl groups.     

锂电解过程中杂质元素的电化学行为

采用循环伏安法研究了锂电解过程中杂质元素的电化学行为。电解过程中杂质元素镁将优先于锂在阴极析出, 然后是金属锂的欠电位沉积形成镁锂合金, 最后才是金属锂的析出, Mg ²⁺的还原电极过程受扩散控制, 扩散系数为1.44×10 ^-5 cm ²/s;微量的Ca ²⁺即发生钙锂共沉积;在含少量氯化钠的熔盐体系中, 杂质元素钠被锂还原并形成合金, 随着电解质体系中氯化钠含量的增加, 金属锂中的钠含量有较大的增加;杂质元素铁优先于锂在阴极析出, 在阴极被还原成海绵铁使阴极钝化, 引起熔盐体系锂的析出电流急剧降低, Fe ³⁺的还原电极过程受扩散控制, 扩散系数为3.14×10 ^-5 cm ²/s。     

金属离子对水热法制备半水硫酸钙晶须的形貌及粒径的影响

以二水硫酸钙为原料,采用水热法制备了半水硫酸钙晶须。通过单因素实验得出制备半水硫酸钙晶须的较优工艺条件为：反应温度120℃、料浆质量分数2%、反应时间2h、搅拌速度200r/min,此时所得晶须产物平均直径2.4μm,长径比103.9,晶须呈长针状、规则统一,分散性好。探讨了K⁺、Mg²⁺、Cu²⁺、Fe³⁺、Al³⁺对较优工艺条件下制备的半水硫酸钙晶须形貌及粒径的影响,结果表明：金属离子对晶须产物形貌及粒径有显著影响。其中低浓度的Mg²⁺、Cu²⁺有助于获得小直径、高长径比的晶须产物;Al³⁺、Fe³⁺对晶须的生长有较强的抑制作用,特别是低浓度的Al³⁺、Fe³⁺使得晶须的形貌发生明显的变化,导致长径比较低;除K⁺外,金属离子浓度越高,所得晶须产物直径越大,长径比越小,并发生团聚现象,晶须由针状变为短棒状,分散性变差。同时探讨了金属离子的作用机理。     

过氧化氢溶液中痕量离子吸附分离用氨基功能化SBA-15的制备及性能

通过后接枝法制备了氨基功能化SBA-15介孔氧化硅(S-N),用于吸附过氧化氢溶液中的金属和阴离子及有机杂质制高纯过氧化氢.研究了接枝量对吸附剂结构和性能的影响并发现S-N中的氮含量随接枝剂用量增加而增加,最高为1.83％.S-N保留了高度有序的六方孔道结构,但比表面积和孔体积均随接枝量增加而下降.在过氧化氢溶液中,各...     

Selective removal of iron(III) from highly salted chloride acidic solutions by solvent extraction using di(2-ethylhexyl) phosphate

Metal ions including Fe³⁺, Ca²⁺, Mg²⁺, Ni²⁺, Co²⁺ and Cu²⁺ are commonly found in the leaching solution of laterite-nickel ores, and the pre-removal of Fe³⁺ is extremely important for the recovery of nickel and cobalt. Di(2-ethylhexyl)phosphate acid (D2EHPA) showed high extraction rate and selectivity of Fe³⁺ over other metal ions. The acidity of the aqueous solution is crucial to the extraction of Fe³⁺, and the stoichiometry ratio between Fe³⁺ and the extractant is 0.86:1.54. The enthalpy for the extraction of Fe³⁺ using D2EHPA was 19.50 kJ/mol. The extraction of Fe³⁺ was ≥99% under the optimized conditions after a three-stage solvent extraction process. The iron stripping effects of different reagents showed an order of H₂C₂O₄>NH₄HCO₃>HCl>NaCl>NaHCO₃>Na₂SO₃. The stripping of Fe was ≥99% under the optimized conditions using H₂C₂O₄ as a stripping reagent.     

镁铝离子共存硅酸体系的聚合行为

通过对镁铝离子共存硅酸体系中硅酸胶凝时间、单硅酸聚合反应速率以及凝胶热性能的研究,得出：在pH<;4的微酸性条件下,硅酸体系的胶凝时间随镁铝离子共存浓度的增大而减小,且铝离子在对硅酸体系的促凝过程中起主要作用。镁铝离子共存硅酸体系的单硅酸反应速率常数比不含金属离子硅酸体系的有所增大,计算得出MA_0.1+0.1硅酸体系的单硅酸平均速率常数为：k₀=7.28×10^-4,k₁=5.62×10^-4。镁铝离子共存硅酸体系凝胶的晶化转变温度与晶型转变温度,相较于不含金属离子硅酸体系的均有所降低,根据热重曲线计算出MA_0.1+0.1硅酸体系水合二氧化硅的化学式为：SiO₂·0.556 H₂O。     

转盘塔内甲基异丁基酮萃取湿法磷酸实验研究

溶剂萃取法是一种经济有效的湿法磷酸净化方法。在转盘塔中,以甲基异丁基酮（MIBK）为萃取剂,开展了净化湿法磷酸的实验研究。考察了搅拌转速、相比对磷酸萃取率、杂质离子选择性、洗涤效果和反萃效果的影响。研究结果表明：萃取过程适宜的相比（溶剂与磷酸的体积比）为4,搅拌转速为200~400 r/min,在此条件下磷酸萃取率为85%;洗涤过程的搅拌转速不应大于100 r/min,适宜的洗涤酸用量为溶剂相体积的10%~15%,在此条件下铁离子（Ⅲ）和镁离子脱除率均在90%以上、铝离子脱除率大于70%、硫酸根脱除率为50%~60%;反萃过程搅拌转速不应大于200 r/min,适宜的反萃水用量为溶剂相体积的9%~15%。MIBK对阳离子的脱除效果较好,但是对阴离子的脱除效果不佳。经过萃取、洗涤和反萃3个过程,磷酸收率为57.8%~70.3%,磷酸中铁离子（Ⅲ）含量可以达到工业级磷酸标准,但是硫酸根的含量无法达标,需要结合其他方法进一步脱除。     

Self-assembly of metal-cholesterol oxidase hybrid nanostructures and application in bioconversion of steroids derivatives

A cholesterol oxidase (COD) was hybridized with Ca²⁺, Zn²⁺, Al³⁺, Fe²⁺ and Mn²⁺. After precipitation with PO₄^3– at 4 °C for 72 h, the resulting pellets were freeze-dried. In scanning electron microscopy assays, the metal-COD complexes revealed flower-like or granular structures after hybridization. Fourier transform infrared spectroscopy assay revealed the characteristic peaks of both the enzyme and metal materials. X-ray diffraction analysis indicated that COD was encapsulated in CaHPO₄·2H₂O-, Zn₃(PO₄)₂·4H₂O-, AlPO₄-, FeP₄- and Mn₃(PO₄)₂·3H₂O-based nanostructures, respectively. Differential scanning calorimetry assay indicated significant increases in thermo-denaturation temperatures from 60.5 °C to 167.02 °C, 167.02 °C, 137.70 °C, 172.85 °C and 160.99 °C, respectively. Using steroid derivatives as substrates, this enzyme could convert cholesterol, pregnenolone, dehydroepiandrosterone, ergosterol, b-sitosterol and stigmasterol to related single products. Hybridization in metal-based nanostructures could significantly enhance the initial conversion ratio and reaction stability of the enzyme. In addition, substrate selectivity could be affected by various metal materials. Briefly, using Ca²⁺, Zn²⁺, Al³⁺, Fe²⁺ and Mn²⁺ as hybrid raw materials could help to encapsulate COD in related metal-enzyme nanostructures, and could help to promote the stability and tolerant properties of the enzyme, while also enhancing its catalytic characteristics.     

不同金属盐破乳对丁基橡胶硫化行为的影响

为考察金属盐凝固剂对丁基橡胶(isobutylene isoprene rubber,IIR)硫化行为的影响,采用流变仪研究了搅拌破乳及11种金属盐破乳后IIR的硫化历程,并分析了其硫化动力学。研究发现金属盐的阳离子及阴离子种类对硫化过程均有显著影响。与传统Ca²⁺凝固剂相比,过渡金属离子Cu²⁺、Zn²⁺破乳会延长焦烧期及正硫化时间,降低硫化表观活化能,硫化膜储能模量较高。与搅拌破乳相比,主族金属离子Ca²、Mg²⁺、Al³⁺破乳对硫化过程影响较小。阴离子Cl^-及NO₃^-有显著的硫化抑制作用,降低硫化表观速率常数,延长正硫化时间;阴离子SO₄^2-和OAc^-对IIR的硫化历程影响较小,相应的IIR硫化胶具有更高的模量。     

Density functional complexation study of metal ions with poly(carboxylic acid) ligands. Part 1. Poly(acrylic acid) and poly(α-hydroxy acrylic acid)

We have studied metal ion complexation with poly(carboxylic acid) ligands using density functional methods and a continuum-solvation model (COSMO). Geometry optimisations have been carried out for metal complexes of poly(acrylic acid-co-maleic acid), poly(methyl vinyl ether-co-maleic acid), and poly(epoxy succinic acid) oligomers. The complexation energies for Mg²⁺, Ca²⁺, Mn²⁺, and Fe³⁺ have been calculated and they have been corrected with previously determined metal specific correction parameters. The most effective ligand for all the metal ions was found to be poly(epoxy succinic acid). With Ca²⁺, poly(epoxy succinic acid) was found to form 6-coordinated complex with three metal-coordinating carboxylate oxygen, two ether oxygens, and one hydroxyl oxygen atom. All the other metals favoured 5-coordinated complexation geometry with four metal-coordinating carboxyl oxygens and one ether oxygen atom.     

Preparation of carbon-based adsorbents from sewage sludge pyrolysis to remove metals from water

The objective of this study was to evaluate the use of cheap carbon-based adsorbents from sewage sludge pyrolysis to remove Na⁺, K⁺, Ca²⁺ and Mg²⁺ from saline water. Four model solutions of NaCl, KCl, CaCl₂ and MgCl₂ that simulated seawater composition were used. The model solutions were 456.54 mmol_c L⁻¹ NaCl, 9.72 mmol_c L⁻¹ KCl, 19.96 mmol_c L⁻¹ CaCl₂ and 111.09 mmol_c L⁻¹ MgCl₂. Two carbon adsorbents, one with chemical activation, were prepared by a new method and evaluated for ion adsorption. The results indicated that carbon adsorbent without chemical activation was the most effective in removing ions from different solutions and the removal of metals followed the sequence: Na⁺ (76.78−69.66) >K⁺ (66.0−57.80) >Mg²⁺ (44.84−42.85) >Ca²⁺ (35.12−12.38). Results showed that it is to possible prepare carbon-based adsorbents from sewage sludge following inexpensive and environmentally acceptable methods.     

The effect of dopants on the activity of MoO3/ZSM-5 catalysts for the dehydroaromatisation of methane

The effect of a number of dopants – Co²⁺, Fe³⁺, Al³⁺, Ga³⁺ and P^(V) – on the catalytic activity of MoO₃/ZSM-5 dehydroaromatisation catalysts has been investigated. Promotional effects were observed with Fe³⁺, Al³⁺ and Ga³⁺, whereas P^(V) added in the form of phosphomolybdic acid decreased the benzene formation rate. Doping with Co²⁺ was not observed to produce any promotional effects, aside from an initial high conversion and burst of hydrogen which was short-lived. In the case of iron, although the benzene formation rate was close to that for the non-doped parent catalyst in the early stages, benzene formation was enhanced at longer times on stream and the addition of iron was observed to enhance methane conversion, principally through enhanced coke formation. The addition of gallium was found to produce an enhancement of benzene production in the early stages of reaction, but its principal effect was the reduction of hydrogen producing side reactions associated with the formation of coke. In comparing the effects of metal ion addition, it is notable that the impregnation solutions of Fe³⁺, Al³⁺ and Ga³⁺ are acidic. Possible effects of these dopants such as zeolite dealumination, modification of catalyst acidity and the formation of mixed molybdenum containing phases or re-dispersion of the MoO₃ phase can be advanced as potential explanations for the observed effects.     

Adsorption equilibrium,kinetics, and dynamic separation of Ca2+ and Mg2+ ions from phosphoric acid-nitric acid aqueous solution by strong acid cation resin

The separation of Ca²⁺ and Mg²⁺ ions from phosphoric acid-nitric acid aqueous solution is very significant for the neutralization process of nitrophosphate fertilizer. This paper studied the adsorption equilibrium, kinetics, and dynamic separation of Ca²⁺ and Mg²⁺ ions by strong acid cation resin, and the effects of phosphoric acid and nitric acid on the adsorption process were investigated. The results reveal that the adsorption process of Ca²⁺ and Mg²⁺ ions in pure water on resin is in good agreement with the Langmuir isotherm model and their maximal adsorption capacities are 1.86 mmol·g^-1 and 1.83 mmol·g^-1, respectively. The adsorption kinetics of Ca²⁺ and Mg²⁺ ions on resin fits better with the pseudo-first-order model, and the adsorption equilibrium in pure water is reached within 10 min contact time, while at the present of phosphoric acid, the adsorption rate of Ca²⁺ and Mg²⁺ ions on resin will go down. The dynamic separation experiments demonstrate that the designed column adsorption is able to undertake the separation of metal ions from the mix acids aqueous solution, but the dynamic operation should control the flow rate of mix acid solution. Besides nitric acid solution was proved to be effective to completely regenerate the spent resin and achieve the recyclable operation of separation process.     

尾矿酸浸液除锰工艺条件研究

金川公司尾矿酸浸液中除含有较高含量的铁和镁之外,还含有一定量的杂质锰。应用热力学原理计算并分析了硫酸锰与次氯酸钠反应的活性,以次氯酸钠为氧化剂、氧化镁为中和剂,通过正交设计与实验,得到了从该酸浸液中除锰的最佳工艺条件,并进行了除锰实验。将除锰滤液进一步除钙以及蒸发浓缩、冷却结晶得到了七水硫酸镁,其主含量为98.4%（质量分数）,符合HG/T 2680-2009《工业硫酸镁》I类一等品质量指标。     

Al3+、Na+和Mg2+对二水硫酸钙结晶的影响

采用CaHPO₄·2H₂O-H₂SO₄-H₃PO₄-H₂O体系模拟湿法磷酸生产过程,以磷矿浆成分为依据,在单因素条件下分别研究Al³⁺、Na⁺和Mg²⁺对结晶和CaSO₄·2H₂O水洗速率的影响。研究发现：添加Al³⁺有利于CaSO₄·2H₂O晶体粒径增加;添加Na⁺使得0.9% Na₂O含量的Na⁺引起CaSO₄·2H₂O晶体团聚,有利于水洗;Mg²⁺增加溶液黏度,严重影响晶体生长和水洗速率。通过X射线衍射、扫描电子显微镜对CaSO₄·2H₂O进行表征,发现其晶体生长符合非完整光滑突变界面模型,杂质离子影响反应速率和晶面生长速度。     

焙烧-水化络合法脱除镁废渣中钙杂质的研究

以含钙镁废渣为原料,采用高温焙烧-EDTA络合法脱除其中的钙杂质制备高纯氧化镁,探究了焙烧温度与时间、EDTA溶液浓度、络合温度、液固质量比与水化时间对钙杂质脱除效果的影响。利用X射线衍射(XRD)、X射线光电子能谱(XPS)等方法对样品结构进行表征。结果表明,镁废渣中钙、镁分别以碳酸钙(CaCO₃)和碱式碳酸镁[4MgCO₃·Mg(OH)₂·4H₂O]形式存在,经过高温焙烧过程分别分解为氧化钙(CaO)和氧化镁(MgO)。热力学计算表明,体系中钙、镁离子与EDTA的络合能力存在较大差异,EDTA与钙离子络合能力强,与镁离子络合能力极弱,络合作用促进CaO溶解,使钙离子进入液相,MgO停留在固相,实现钙、镁分离。在800℃、0.5 h、c(EDTA)=0.01 mol/L、液固质量比为80∶1、常温水化时间为2.0 h时,钙脱除率达到98.78%,产物经105℃烘干8.0 h,MgO纯度大于99.00%。     

高铁煤矸石酸浸液合成氧化铁红的实验研究

以高铁煤矸石为原料,先用硫酸酸浸的方法获得含有铝离子的硫酸铁溶液;采用分步沉淀的方法,使Fe3+完全转化为氢氧化铁凝胶而与Al³⁺分离;再将获得的氢氧化铁凝胶烘干后高温煅烧;最后将煅烧产物磨粉过筛,获得了氧化铁红。确定了合成氧化铁红的工艺条件是：酸浸液中铁离子的浓度为0.31 mol/L;分离Fe³⁺与Al³⁺时,氢氧化钠溶液的浓度为1 mol/L,且控制终点pH在3.0左右;干凝胶焙烧温度为800 ℃,时间为60 min。XRD及化学分析结果表明：所得产物为氧化铁红,符合GB/T 1863-2008《氧化铁颜料》的相关要求。     

Fe2+/Fe3+和Mn2+对低氧曝气过程总氮去除与转化途径的影响

为短期快速实现实际生活污水自养脱氮,采用含有厌氧氨氧化菌的实际污水处理厂活性污泥,针对Fe²⁺/Fe³⁺和Mn²⁺对低氧曝气过程中氮的去除效果进行了研究,分析确定了氮素转化的途径。研究结果表明,Fe²⁺/Fe³⁺和Mn²⁺均可提高活性污泥中厌氧氨氧化菌（AnAOB）丰度,但由于Fe²⁺/Fe³⁺对氨氧化菌（AOB）也存在一定抑制作用,因此,短期投加Fe²⁺/Fe³⁺条件下,低氧曝气过程中总无机氮去除率为25%,但投加Mn²⁺条件下总无机氮去除率可达44%。通过氮素平衡分析,发现投加Fe²⁺/Fe³⁺条件下,氮素主要通过反硝化作用去除;而投加Mn²⁺条件下,氮素主要通过厌氧氨氧化（anammox）作用去除。因此,传统活性污泥可通过短期投加Mn²⁺增强厌氧氨氧化活性,促进低氧曝气过程中氮的去除,利于快速实现一体化自养脱氮。