氟化锰沉淀法除去硫酸锰中钙镁的工艺研究

本文采用氟化锰沉淀法脱除硫酸锰溶液中的钙、镁离子,考察了反应时间、反应温度、溶液pH值、氟化锰的用量等因素对钙镁离子脱除效果的影响。实验结果表明,当氟化锰的用量系数为1.5R、温度为90℃、pH=4、反应时间为60min时,钙、镁杂质的脱除效果最佳。反应中,适当加入硫酸铝,可使胶体颗粒絮凝成较大的颗粒而快速沉淀,并可除去溶液中少量的氟离子。     

脱盐废水中钙镁离子脱除技术的研究

以"烧碱-纯碱"的方法对脱盐废水中钙镁离子的脱除进行了研究,以原子吸收分光光度计测定脱除前后的钙镁离子含量。采用正交试验法探讨了温度、两碱用量、反应时间、陈化时间四个因素对钙镁离子脱除率的影响,综合比较找出了最优条件:25℃下,两碱用量为理论量的1.2~1.4倍,反应时间为1h,陈化时间为2h,此条件下钙镁离子脱除效果最好,钙离子脱除率达96%以上,镁离子脱除率平均可达90%。     

过硫酸铵在铁锰杂质脱除中的应用

研究了过硫酸铵在硫酸锌溶液脱除铁锰杂质中的应用,采用过硫酸铵作氧化剂,活性氧化锌和活性炭作吸附剂,从而使铁锰离子的脱除效果大为提高,达到１×１０－８（质量分数）。完全可以代替高锰酸钾氧化法用在生产中。     

络合沉淀法脱除湿法磷酸中铝镁杂质的统计分析

采用化学沉淀法脱除湿法磷酸中的铝、镁、氟杂质.采用硝酸铵和氢氟酸对粗湿法磷酸进行处理,从而使镁和铝杂质以一种很容易分离的络合物[(NH4)xMgyAlz(F,OH)6·2H2O]沉淀出来.从络合物化学式可以看出,原湿法磷酸中铵离子、铝离子和氟离子的含量对构成这种络合物的影响很明显,因此,采用这3种因素(铵离子、铝离子和氟离子加入量)来做正交回归实验设计.最后得出结论,原湿法磷酸中铝的含量是镁沉淀量的制约因素,因此,要完全脱去湿法磷酸中主要的杂质镁,可以额外地加入可溶性的铝盐,同时加入氢氟酸和硝酸铵.通过多次实验,最后得到最优的反应条件,杂质脱除也有很好的效果.因此,此方法对磷酸中杂质的脱除是有意义的.     

镁钙锌铝四元类水滑石金属含量的测定研究

论述了镁-钙-锌-铝四元合成类水滑石中含量相差悬殊的4种金属元素含量的测定方法:第一份试液,以氟化铵掩蔽铝、镁、钙离子后,用乙二胺四乙酸二钠(EDTA)标准溶液滴定锌离子;第二份试液,用缓冲溶液调节pH为3.5,加过量EDTA煮沸处理,再调节pH为4.2,促使铝离子和锌离子全部与EDTA络合,以铜离子标准溶液滴定剩余的EDTA后,用取代络合滴定法测定铝离子;第三份试液,用小体积沉淀法处理,形成碳酸钙和氢氧化镁沉淀,与溶于水的偏锌酸根(ZnO2-2)和偏铝酸根(AlO-2)分离,再使碳酸钙与氢氧化镁溶于盐酸溶液,用EDTA滴定钙-镁总量;向第四份钙-镁溶液中加入乙二醇二乙醚二胺四乙酸钡(Ba-EGTA)-硫酸钠溶液掩蔽钙离子,用EDTA标准溶液滴定镁离子,以差减法计算钙离子含量.该法准确度和精密度均较高,能满足工业分析要求.     

吸附污水钙镁离子及增粘效果

大庆油田某区块采出污水富含高浓度钙镁离子,研究钙镁离子对回注水配制聚合物溶液粘度的影响。利用草炭与NaOH配制腐殖酸钠混合液络合采出污水中的钙镁离子,降低钙镁离子对聚合物溶液粘度的影响,使采出污水达到油田回注粘度标准。研究表明,Ca⁽²⁺⁾、Mg(2+)、Mg⁽²⁺⁾含量在0(2+)含量在0²00mg/L时聚合物溶液粘度严重损失,粘度损失率分别达到最大值63.2%和70.7%;采用腐殖酸钠络合钙镁离子时,腐殖酸钠溶液用量为8.0mL时对钙离子的吸附率达到77.50%,腐殖酸钠混合液用量为6.0mL时对镁离子的吸附率达到83.60%,说明腐殖酸钠对钙、镁离子吸附效果良好。室内实验结果证实了利用腐殖酸钠络合钙镁离子防止聚合物溶液粘度降低的可行性,为现场试验提供参考。     

微波消解-EDTA滴定法测定红土镍矿中氧化镁含量

以盐酸、硝酸、氢氟酸溶解红土镍矿样品,加高氯酸冒烟除去硅和氟,采用六次甲基四胺-铜试剂消除共存离子干扰,在pH=10时,以铬黑T作指示剂,用Na2EDTA标准滴定溶液滴定钙和镁的合量;在pH=12时,以钙羧酸作指示剂,用Na2EDTA标准滴定溶液滴定钙的含量,用差减法求得镁的含量。氧化镁质量分数在5.0%~30.0%范围内,该方法加标回收率为99.4%~100.0%,重复性及再现性方程分别为r=0.005m+0.0899和R=0.0091m+0.3553。此方法适合于测定氧化镁含量在5.0%~30.0%的红土镍矿。     

吸附污水钙镁离子及增粘效果

大庆油田某区块采出污水富含高浓度钙镁离子,研究钙镁离子对回注水配制聚合物溶液粘度的影响。利用草炭与NaOH配制腐殖酸钠混合液络合采出污水中的钙镁离子,降低钙镁离子对聚合物溶液粘度的影响,使采出污水达到油田回注粘度标准。研究表明,Ca~(2+)、Mg~(2+)含量在0~200mg/L时聚合物溶液粘度严重损失,粘度损失率分别达到最大值63.2%和70.7%;采用腐殖酸钠络合钙镁离子时,腐殖酸钠溶液用量为8.0mL时对钙离子的吸附率达到77.50%,腐殖酸钠混合液用量为6.0mL时对镁离子的吸附率达到83.60%,说明腐殖酸钠对钙、镁离子吸附效果良好。室内实验结果证实了利用腐殖酸钠络合钙镁离子防止聚合物溶液粘度降低的可行性,为现场试验提供参考。     

一种铅钙锌镁铝五元类塑料热稳定剂中金属含量测定的探索

介绍了铅-钙-锌-镁-铝五元类塑料热稳定剂中金属含量的测定方法:第一份试液,以三乙醇胺掩蔽铁等离子后,调pH为12,用EDTA滴定钙离子;第二份试液,调pH为3.5,加过量EDTA煮沸处理,再调节pH为4.2,促使铝和锌全部与EDTA络合,以锌盐标准溶液滴定剩余的EDTA,加氟化铵解蔽ED-TA-Al,再用锌盐标准溶液滴定释放出的EDTA,计算出铝的含量;第三份试液,用硫酸分离铅钙和锌镁铝,沉淀用醋酸-醋酸钠溶液溶解,用EDTA滴定铅离子含量,溶液用于锌镁的分析测试;第四份试液,取除掉钙铅的溶液一份调pH为5.5,加氟化铵掩蔽铝等离子后,用EDTA滴定锌离子;第五份试液,取除掉钙铅的溶液一份调pH为8.5趁热过滤以除去锌和铝。调pH为10,用EDTA滴定镁。该法准确度和精密度均较高,能满足工业分析要求。     

氟化锰去除含锰硫酸溶液中钙、镁、锂的工艺研究

本文采用氟化锰沉淀法去除废旧锂离子电池浸出液中的钙、镁离子的同时,去除了大部分锂离子,考察了氟化锰的用量、溶液pH值、反应温度及反应时间等因素对钙、镁、锂离子沉淀率的影响.实验结果表明,当氟化锰的用量系数为1.5R2、pH=4、反应温度为60℃、反应时间为1.5 h时,钙、镁杂质的脱除效果最佳,此时钙、镁、锂的沉淀率分...     

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.     

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%。     

基于水溶性探针法测镁的高纯碳酸锂快速质检

碳酸锂生产过程及最终产品中,微量镁的掺杂会直接影响碳酸锂的产品品质及其下游产品的加工应用,而高纯碳酸锂中微量镁的快速检测仍是一个难点。研究提出利用水溶性荧光探针检测碳酸锂中微量镁的方法,以水溶性极强的三(羟甲基)氨基甲烷对2-(2-羟基苯基)苯并噁唑进行修饰,构建了具有高灵敏度和高选择性的水溶性Mg²⁺荧光探针A。该方法可实现对碳酸锂溶液中Mg²⁺的快速荧光检测,并确定了探针A被Mg²⁺所激发的荧光信号强度与Mg²⁺浓度之间的定量关系。结果表明在水溶条件下检测含镁杂质的碳酸锂时,该方法对微量镁的检出限为2.014 9μmol/L,检测工作曲线相关系数达到0.991 5,检测灵敏度高,对高纯碳酸锂中微量镁的检测时间为3.666 s,可实现对Mg²⁺的快速质检。     

阳离子类型对粉煤灰混凝土氯离子扩散性能的影响

通过快速氯离子迁移系数法(RCM法)和自然扩散法研究了钾、钠、钙、镁四种阳离子类型的氯盐对粉煤灰混凝土氯离子扩散性能的影响,基于分子动力学模拟,对比分析了K⁺、Na⁺、Ca²⁺、Mg²⁺、Cl^-五种离子在水溶液中的径向分布函数和均方位移曲线。结果表明:粉煤灰混凝土的氯离子扩散系数主要受阳离子价态的影响,价态越高,扩散系数越大;扩散系数随着氯离子浓度增加先增大后减小,随着粉煤灰掺量增加先减小后增大;阳离子类型影响氯离子扩散性能的原因是离子扩散能力不同,其中各离子水合能力强弱顺序为Mg²⁺＞Ca²⁺＞Na⁺＞K⁺>Cl^-,自扩散系数大小顺序为Mg²⁺＞Ca²⁺＞Cl^-＞K⁺>Na⁺。MgCl₂中的Mg²⁺和Cl^-对粉煤灰混凝土都有侵蚀作用,且Mg²⁺会抑制粉煤灰活性的激发。     

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。     

柴达木盆地南翼山背斜构造区卤水自然蒸发实验

柴达木盆地南翼山背斜构造区卤水属高钙、低镁的氯化钙型卤水,微量元素硼、锂、锶、碘等含量相对较高,具有较高的综合利用价值。选取南翼山背斜构造区约3 000 m处深层卤水在自然状态下蒸发结晶,分析各种离子在固、液相中的分布规律、盐类结晶规律、结晶形态及微量离子的富集规律。结果表明:在室外自然状态下蒸发时,析出的盐中发现了不常见的异性结构的石盐、钾石盐和疑似K（NH₄）Mg₂Cl₆·12H₂O的类光卤石;石盐阶段和钾石盐阶段析盐规律符合Na⁺,K⁺,Mg²⁺//Cl^-—H₂O 相图,钾石盐、光卤石、南极石阶段符合K⁺,Na⁺,Ca²⁺,Mg²⁺//Cl^- —H₂O体系25 ℃简干图;微量离子中,Li ⁺、Br^-、I^-一直富集,其他离子在蒸发后期有不同程度的析出,三氧化二硼可以富集至18.77 g/L,Li⁺最高可以富集至6.520 g/L。蒸发所得的钾混盐是提钾优质原料,实验结果可以为后期综合利用提供参考。     

鸭湖构造深部卤水自然蒸发实验研究

通过自然蒸发实验,对鸭湖背斜构造深部卤水进行了研究,得到了该卤水在自然蒸发过程中各元素富集规律及析盐规律。受高含量钙影响,卤水蒸发路线在K⁺,Na⁺,Mg²⁺//Cl^--H₂O（25 ℃）介稳相图中偏移比较明显,可与Na⁺,K⁺,Mg²⁺,Ca²⁺//Cl^--H₂O（25 ℃,对NaCl饱和）介稳相图相结合对实验数据进行分析。卤水自然蒸发过程中矿物析出顺序为：石膏→石盐→光卤石→南极石→溢晶石;光卤石产量较小并且质量不高;锂最终浓缩至质量浓度约为2.9 g/L时,硼、锶、溴、碘、铷、铯等微量元素均有析出。实验数据和结论为针对该类型卤水进行更深入的综合开发利用研究提供了依据,如前期除钙后梯度提取硼酸、碳酸锂、溴素等产品。     

Investigation of solution chemistry to enable efficient lithium recovery from low-concentration lithium-containing wastewater

In the production of lithium-ion batteries (LIBs) and recycling of spent LIBs, a large amount of low-concentration lithium-containing wastewater (LCW) is generated. The recovery of Li from this medium has attracted significant global attention from both the environmental and economic perspectives. To achieve effective Li recycling, the features of impurity removal and the interactions among different ions must be understood. However, it is generally difficult to ensure highly efficient removal of impurity ions while retaining Li in the solution for further recovery. In this study, the removal of typical impurity ions from LCW and the interactions between these species were systematically investigated from the thermodynamic and kinetics aspects. It was found that the main impurities (e.g., Fe³⁺, Al³⁺, Ca²⁺, and Mg²⁺) could be efficiently removed with high Li recovery by controlling the ionic strength of the solution. The mechanisms of Fe³⁺, Al³⁺, Ca²⁺, and Mg²⁺ removal were investigated to identify the controlling steps and reaction kinetics. It was found that the precipitates are formed by a zero-order reaction, and the activation energies tend to be low with a sequence of fast chemical reactions that reach equilibrium very quickly. Moreover, this study focused on Li loss during removal of the impurities, and the corresponding removal rates of Fe³⁺, Al³⁺, Ca²⁺, and Mg²⁺ were found to be 99.8%, 99.5%, 99%, and 99.7%, respectively. Consequently, high-purity Li₃PO₄ was obtained via one-step precipitation. Thus, this research demonstrates a potential route for the effective recovery of Li from low-concentration LCW and for the appropriate treatment of acidic LCW.     

Flux mechanism of compound flux on ash and slag of coal with high ash melting temperature

The melting temperature of Z coal ash was reduced by adding calcium–magnesium compound flux(W_(CaO)/W_(MgO)=1). In the process of simulated coal gasification, the coal ash and slag were prepared. The transformation of minerals in coal ash and slag upon the change of temperature was studied by using X-ray diffraction(XRD). With the increase of temperatures, forsterite in the ash disappears, while the diffraction peak strength of magnesium spinel increases,and the content of the calcium feldspar increases, then the content of the amorphous phase in the ash increases obviously. The species and evolution process of oxygen, silicon, aluminum, calcium, magnesium at different temperatures were analyzed by X-ray photoelectron spectroscopy(XPS). The decrease of the ash melting point mainly affects the structural changes of silicon, aluminum and oxygen. The coordination of aluminum and oxygen in the aluminum element structure, e.g., tetracoordinated aluminum oxide, was changed. Tetrahedral [AlO_4] and hexacoordinated aluminoxy octahedral [AlO_6] change with the temperature changing. The addition of Ca~(2+) and Mg~(2+) destroys silica chain, making bridge oxide silicon change into non-bridge oxysilicon; and bridge oxygen bond was broken and non-bridge oxygen bond was produced in the oxygen element structure. The addition of calcium and magnesium compound flux reacts with aluminum oxide tetrahedron, aluminum oxide octahedron and silicon tetrahedron to promote the breakage of the bridge oxygen bond. Ca~(2+) and Mg~(2+) are easily combined with silicon oxide and aluminum oxide tetrahedron and aluminum. Oxygen octahedrons combine with non-oxygen bonds to generate low-melting temperature feldspars and magnesite minerals, thereby reducing the coal ash melting temperatures. The structure of kaolinite and mullite was simulated by quantum chemistry calculation, and kaolinite molecule has a stable structure.     

轻烧粉蒸氨液中杂离子对氢氧化镁晶体的影响

以轻烧粉精制液和氨气为原料,研究了蒸氨精制液中杂质离子对氢氧化镁形貌的影响。选取阳离子NH4+、Ca2+和阴离子SO42-作为研究对象,考察了其对氢氧化镁的形貌和颗粒大小的影响。采用扫描电镜（SEM）、X射线衍射仪（XRD）和激光粒度仪对产品进行表征。结果表明,NH4+、Ca2+对氢氧化镁产品的性能影响较小,而SO42-对氢氧化镁产品的形貌和粒径影响较显著。并利用氯化钡除去溶液中的SO42-,比较未除硫、除硫后与用纯氯化镁制备的产品的差别。