硫酸化焙烧——水浸法从镍精矿中同步提取金属及矿相转化（英文）

提出低温NH₄HSO₄焙烧—水浸工艺从金川镍精矿中同步提取Ni、Cu和Co,并系统研究硫酸化焙烧和水浸出过程中一些因素对金属提取的影响。结果表明,在优化的焙烧和水浸条件下,95.7%Ni、98.9%Cu和96.8%Co被提取。利用TG-DTA、XRD、SEM和EDS等手段分析矿相的转化机理,在NH₄HSO₄及其分解的SO₃和NH3的硫酸化反应下,有价金属被转化为水溶性金属—铵配合物从而得到有效的提取。通过提高浸出温度使铁离子与铵离子结合形成NH₄[Fe₃(SO₄)₂(OH)₆]沉淀可除去浸出液中的杂质铁。在焙烧过程中收集的挥发物为(NH₄)₂SO₄和(NH₄)₂SO₃,可用作硫酸化焙烧的试剂。     

烟道气氨法脱硫液对Q235碳钢腐蚀研究

采用静态挂片、极化曲线和长期点蚀实验，研究了氨法脱硫浆液中F^-和Cl^-以及 (NH₄)₂SO₄对Q235碳钢腐蚀的影响。结果表明，Q235碳钢在含卤硫铵溶液中的均匀腐蚀速率随F^-浓度和Cl^-浓度增大均呈现先降低后增高的趋势，随着 (NH₄)₂SO₄质量分数增加，均匀腐蚀速率降低；随着F^-浓度的增大，自腐蚀倾向增加；随着Cl^-浓度以及 (NH₄)₂SO₄质量分数的增大，自腐蚀倾向均降低；Q235碳钢在氨法脱硫模拟浆液中点蚀较严重，需采取重防腐措施。     

大气污染物硫酸铵和氯化钠混合盐粒沉降对电路板铜大气腐蚀的加速机制

采用电化学阻抗 (EIS)、石英晶体微天平 (QCM) 和铜箔电阻探针 (TER) 等多种大气腐蚀测量技术,以表面沉积不同比例 (NH₄)₂SO₄和NaCl混合盐粒下的电路板铜箔为样本,在气候试验箱中模拟研究了电路板铜在模拟污染大气环境下的初期大气腐蚀行为。结果表明：在30 ℃ RH90%环境中且表面沉积量相同时,在腐蚀初期 (<30 h),(NH₄)₂SO₄和NaCl混合盐粒对铜的腐蚀性比沉积单一NaCl盐粒的体系更强;但30 h后,情况发生反转,混合盐粒对铜的腐蚀相比单一 NaCl 盐粒体系反而显著降低,且当混合比例为 1∶1 时,(NH₄)₂SO₄对NaCl 腐蚀的抑制作用最强 (抑制比达 84%)。通过腐蚀产物的 SEM、XRD、XPS 分析可知,在腐蚀前期,由于NH₄⁺对Cu的腐蚀促进作用使铜表面快速形成了较为致密的Cu_2...     

High performance of HNaV6O16·4H2O nanobelts for aqueous zinc-ion batteries with in-situ phase transformation by Zn(CF3SO3)2 electrolyte

Zn(CF₃SO₃)₂as an electrolyte has been widely used to improve the electrochemical performance for ZIBs due to that the bulky CF₃SO₃-can reduce the solvation effect of Zn²⁺and promote the ionic diffusion.Herein,we found that Zn(CF₃SO₃)₂electrolyte can induce different electrochemical mechanisms from ZnSO₄electrolyte.Compared to the ZnSO⁴electrolyte,the HNaV₆O₁₆·4H2_Oelectrode with Zn(CF₃SO₃)₂electrolyte exhibits a high capacity of 444 mAh·g^-1at 500 mA·g^-1with a capacity retention of 92.3%after 80 cycles.Even,at a high rate of 5 Ag-1,the HNaV₆O₁₆·4H₂O electrode delivers an initial discharge capacity of 328 mAh·g^-1with a capacity retention of 93.7%after 1000 cycles.Differing from the mechanism with ZnSO4 electrolyte,the excellent cycle stability of HNaV₆O₁₆·4H₂Oelectrode can be attributed to the in-situ phase transformation to ZnxV₂O₅·nH₂O based on the co-intercalation of Zn²⁺/H⁺.     

改性铁基磁性材料的制备及其对水中Cd(Ⅱ)的吸附

本文通过氨性浸出方式处理吸附Cd(Ⅱ)之后的零价铁材料(Fe≡Cd),使表面吸附的Cd(Ⅱ)脱附同时对材料改性,获得了一种新的改性铁基磁性材料(MFe)。基于紫外光谱、溶液化学和量子化学分析,证实了Fe≡Cd上的Cd(Ⅱ)与游离NH₃结合形成Cd-NH₃配合物从而实现脱附的可行性。结果表明：(NH₄)₂SO₄和NH₃·H₂O浸出可以有效脱附Fe≡Cd表面的Cd(Ⅱ)。脱附改性后材料的结构性质发生了明显改变,生成了大量吸附活性强的铁(羟基)氧化物,且—NH₂基团成功修饰在材料表面,为Cd(Ⅱ)提供了更多的吸附位点。改性磁性材料(MFe)对Cd(Ⅱ)的吸附量较Fe⁰(Q_e=23.5 mg/g)明显提升,达47.0 mg/g,且循环再生性能良好,可高效循环6次以上。     

废旧磷酸铁锂电池高值回收制备磷酸铁锂材料

针对传统湿法冶金回收废旧磷酸铁锂电池存在含磷废水排放量大、产品附加值低等问题，提出一种还原酸浸-沉淀-固相再生回收废旧磷酸铁锂正极材料的新方法。区别于传统氧化酸浸，本研究在浸出过程中加入有机还原剂，将铁元素以Fe²⁺的形式浸出到溶液中；然后，通过控制pH值制备Fe₃(PO₄)₂·8H₂O，以此作为再生LiFePO₄正极材料的前驱体，避免了后续混锂烧结过程中Fe³⁺还原不彻底、再生磷酸铁锂纯度低等问题。结果表明：通过控制浸出条件，Li⁺和Fe²⁺的浸出率分别达到98.15%和98.10%。利用氨水调控浸出液pH值，沉淀出形貌为一次片状簇拥成团状结构的Fe₃(PO₄)₂·8H₂O前驱体；最后，将Fe₃(PO₄)₂·8H₂O...     

Two sandwich-type uranyl-containing polytungstates catalyze aerobic synthesis of benzimidazoles

<正>Diversified synthetic strategies are extremely important for the structural diversity of uranium-containing polyoxometalates (U-POMs) and their functional expansion.Herein,two sandwich-type U-POMs were reported,which are Na_5.6K_6.4[(UO₂)(H₂O)(TeW₉O₃₃)]₂·21H₂O (UTeW₉)and Na_8.9K_2.7H_1.19[K_0.79(UO₂)_2.21(PW₉O₃₄     

复合电解液中TiO2纳米管阵列的制备及光生阴极保护性能

采用二次阳极氧化法在3种不同的含氟电解质 (F^-、BF₄^-、F^--BF₄^-) 中制备了 TiO₂纳米管阵列。通过SEM、XRD、UV-vis DRS、PL 等手段对所制备的 TiO₂纳米管阵列形貌、结构、光响应能力以及光生载流子分离效率进行对比研究,同时在开闭可见光条件下进行光电化学性能测试。结果显示,用含NH₄F、NH₄BF₄和H₂O 的乙二醇复合电解液制备的TiO₂纳米管阵列相比于传统单种含氟电解液,具有更规整的结构,光吸收更强,光生载流子分离效率更高,对304不锈钢具有更好的光生阴极保护作用。     

废旧锂离子电池火法冶炼富锰渣中锰和锂的提取（英文）

开展富锰渣硫酸化焙烧-水浸选择性提取锰和锂的试验,采用XRD、TG-DSC和SEM-EDS详细分析锰和锂的提取机理。结果表明,在酸浓度为82%(质量分数)、酸矿质量比1.5:1、焙烧温度800℃和焙烧时间2 h时,Mn和Li的浸出率分别达到73.71%和73.28%。焙烧过程中,富锰渣首先与浓硫酸反应形成Mn SO₄、MnSO₄·H₂O、Li₂Mg(SO₄)₂、Al₂(SO₄)₃和H₄SiO₄。随着焙烧温度的升高,H₄SiO₄和Al₂(SO₄)₃依次分解,并形成莫来石和尖晶石相。莫来石的形成有利于降低Al和Si的浸出率而增加Li的浸出率;而尖晶石的形成则会降低Mn和Li的浸出率。     

CH4-O2/H2O(g)白云石煅烧与CO2富集系统研究

白云石煅烧是皮江法炼镁的第一步，存在CO₂排放严重、能耗高等问题。为减少白云石煅烧工艺CO₂排放，创建了基于CH₄-O₂/H₂O(g)燃烧技术的白云石煅烧及其CO₂富集系统，可富集白云石分解和燃料燃烧产生的全部CO₂,实现CO₂净零排放。通过Aspen plus建立系统换热网络，探究了系统热效率和火用效率随运行参数的变化，并分别以热效率最大和火用效率最大为目标对系统进行了优化。以单炉产能为150 t/d的白云石煅烧体系为例，该工艺CH₄燃烧量为5.184 mol/(kg-CaMg(CO₃)₂),具有每年约460万吨的CO₂资源化回收潜力。热力学优化结果表明：当H₂O(g)掺入量为9.02 mol/(kg-CaMg(CO₃)₂)、CH₄燃烧温...     

Separation and Precipitation of Nickel from Acidic Sulfate Leaching Solution of Molybdenum-Nickel Black Shale by Potassium Nickel Sulfate Hexahydrate Crystallization

Nickel was separated and precipitated with potassium nickel sulfate hexahydrate [K₂Ni(SO₄)₂·6H₂O] from acidic sulfate solution, a leach solution from molybdenum-nickel black shale. The effects of the potassium sulfate (K₂SO₄) concentration, crystallization temperature, solution pH, and crystallization time on nickel(II) recovery and iron(III) precipitation were investigated, revealing that nickel and iron were separated effectively. The optimum parameters were K₂SO₄ concentration of 200 g/L, crystallization temperature of 10°C, solution pH of 0.5, and crystallization time of 24 h. Under these conditions, 97.6% nickel(II) was recovered as K₂Ni(SO₄)₂·6H₂O crystals while only 2.0% of the total iron(III) was precipitated. After recrystallization, 98.4% pure K₂Ni(SO₄)₂·6H₂O crystals were obtained in the solids. The mother liquor was purified by hydrolysis-precipitation followed by cooling, and more than 99.0% K₂SO₄ could be crystallized. A process flowsheet was developed to separate iron(III) and nickel(II) from acidic-sulfate solution.     

Electrochemical characteristics of 316l stainless steel processed with a thermally treated Ni- and Cr-rich surface coating

The influence of a thermally treated Ni-Cr rich protective coating on the corrosion behavior and contact resistance of stainless steel in a 0.1NH₂SO₄+ 2 ppmHF electrolyte at 80 °C was evaluated using electrochemicals, interfacial contact resistance (ICR) measurements and X-ray photoelectron spectroscopy. Through a low-cost, continuous production line, the Ni-rich coating film for stainless steels was developed by dipping steel samples in acrylic resin and CrO₃ solutions with different levels of NiSO₄·6H₂O added as a nickel source. Each sample was then heated at 800 for 10 min in a hydrogen-reducing environment. It was shown that an increase in residual Ni content in the surface coating noticeably lowered the interfacial contact resistance and raised the corrosion resistance, depending on the remaining nickel content and the thickness of the surface coatings. In support of the XPS depth profile, this was ascribed to the relative enrichment of the Ni element and the detectable reduction of oxygen content in the coating, which could be associated with the significant evaporation of acrylic resin that occurred during thermal treatment. The optimum Ni composition in the resultant coating film, achieved through the addition of 15 wt.% NiSO₄·6H₂O to the acrylic resin and CrO₃ solution, was estimated to be about 10 wt.%.     

Sulfate-induced hot corrosion of nickel

Nickel specimens with layers of Na₂SO₄ deposited on the metal surface have been reacted in O₂+4% SO₂ in the temperature range 660–900°C. At temperatures from 671°C (the eutectic temperature of Na₂SO₄+NiSO₄ liquid solutions) to 884°C (the melting point of Na₂SO₄), molten Na₂SO₄+NiSO₄ is formed in the scales above critical pressures of SO₃, and the molten sulfate causes accelerated hot corrosion of nickel. The rapid hot corrosion is preceded by an incubation period during which Na₂SO₄+NiSO₄ solid solutions and eventually molten sulfate are formed. The critical SO₃ pressures for formation of molten sulfate as a function of temperature have been delineated through experimental observations, and these are in agreement with theoretical estimates. When only solid solutions of Na₂SO₄+NiSO₄ can be formed, the reactions are slower than specimens with no Na₂SO₄ layer. The reaction mechanism is concluded to involve inward transport of SO₃/NiSO₄ and of oxygen through the molten sulfate distributed as a network in the NiO layer of the outer part of the scale. Beneath the NiO/molten sulfate layer, the scale consists of NiO with a network of Ni₃S₂. Sulfur, present as (Ni-S)_liq, is enriched at the metal/scale interface. Nickel diffuses outward through the Ni₃S₂ network in the inner layer to the boundary of the NiO/molten sulfate layer, where it reacts with the inwardly diffusing oxygen and SO₃/NiSO₄. The enrichment of sulfur next to the metal is concluded to be due to inward sulfur transport in the NiO+Ni-sulfide layer.     

On the reaction mechanism of nickel with SO2+O2/SO3

High-purity nickel has been reacted with 96% O₂+4% SO₂ at 700–900°C. The reaction has been studied at 700°C as a function of the total gas pressure (0.06–1 atm) and at 1 atm as a function of temperature (700–900°C). The reaction mechanism changes with the effective pressure of p(SO₃) in the gas. When NiSO₄ (NiO + SO₃ = NiSO₄) is formed on the scale surface, the scale consists of a two-phase mixture of NiO + Ni₃S₂; in addition, sulfur is enriched at the metal/scale interface. A main process in the reaction is rapid outward diffusion of nickel through the Ni₃S₂ phase in the scale; the nickel reacts with NiSO₄ to yield NiO, Ni₃S₂, and possibly NiS as an intermediate product. When NiSO₄ cannot be formed, the scale consists of NiO, and small amounts of sulfur accumulate at the metal/scale interface. It is proposed that the reaction under these conditions is primarily governed by outward grain boundary diffusion of nickel through the NiO scale, and in addition, small amounts of SO₂ migrate inward through the scale—probably along microchannels.     

The reaction of nickel with SO2 + O2/SO3 at 500–900°C

The reaction of high purity nickel with SO₂ + O₂ mixtures at 500–900°C has been studied. Measurements have been done in gas mixtures with different SO₂/O₂ ratios and as a function of the total gas pressure of the system. Rapid corrosion rates are observed under conditions where NiSO₄ may be formed on the scale surface and the primary reaction products are NiO and Ni₃S₂. Corrosion rates are faster when the Ni specimens are surrounded by a Pt catalyst. It is concluded that the reaction mechanism involves an SO₃ adsorption equilibrium on the surface followed by formation of NiSO₄. The sulfate, in turn, reacts with nickel diffusing rapidly in a sulfide network in the scale to give NiO and Ni₃S₂.     

The high temperature corrosion of nickel in SO2 at 500–800°C

The reaction of nickel with SO₂ has been studied at 500–800°C and different pressures of SO₂ (0.4–100 kPa). The reaction products are NiO and nickel sulphides. The reaction rate goes through a maximum at about 600°C at and above 13 kPa SO₂, while the maximum is absent at lower SO₂ pressures. It is concluded that the reaction takes place through different reaction paths: (i) the direct reaction of Ni with SO₂ and (ii) a reaction path via NiSO₄ as an intermediate reaction product. The latter path is the more rapid one and gives rise to the very rapid reaction rates and maximum in the reaction rate at 600°C.     

Some aspects of the mechanism of high-temperature oxidation of nickel in SO2

A number of investigations on the mechanism of reaction of nickel with SO₂ has been summarized. The calculation results of the equilibrium gas composition in homogeneous SO₂+O₂ mixtures are described over wide ranges of temperatures (500–1100°C) and initial gas compositions. The Ni–O–S phase diagram at 540°C has been compared with data on the stability of interaction products under conditions close to equilibrium. The catalytic activity of NiO has been verified to accelerate the attainment of thermodynamic equilibrium in the SO₂–O₂–SO₃ system. The most effective catalytic activity of NiO occurred at 650–800°C. A monolayer (6 Å) of NiSO₄ was detected on the scale surface by ESCA. This surface phase is assumed to be formed either as an activated complex on the NiO catalyst or as the locally stable NiSO₄ phase. Both assumptions lead to a possible recognition of the sulfate intermediate mechanism.     

Extraction of arsenic from arsenic-containing cobalt and nickel slag and preparation of arsenic-bearing compounds

The arsenic extraction from the arsenic-containing cobalt and nickel slag, which came from the purification process of zinc sulfate solution in a zinc smelting factory, was investigated. The alkaline leaching method was proposed according to the mode of occurrence of arsenic in the slag and its amphoteric characteristic. The leaching experiments were conducted in the alkaline aqueous medium, with bubbling of oxygen into the solution, and the optimal conditions for leaching arsenic were determined. The results showed that the extraction rate of arsenic was maximized at 99.10% under the optimal conditions of temperature 140 °C, NaOH concentration 150 g/L, oxygen partial pressure 0.5 MPa, and a liquid-to-solid ratio 5:1. Based on the solubilities of As₂O₅, ZnO and PbO in NaOH solution at 25 °C, a method for the separation of As in the form of sodium arsenate salt from the arsenic-rich leachate via cooling crystallization was established, and the reaction medium could be fully recycled. The crystallization rate was confirmed to reach 88.9% (calculated on the basis of Na₃AsO₄) upon a direct cooling of the hot leachate down to room temperature. On the basis of redox potentials, the sodium arsenate solution could be further reduced by sulfur dioxide (SO₂) gas to arsenite, at a reduction yield of 92% under the suitable conditions. Arsenic trioxide with regular octahedron shape could be prepared successfully from the reduced solution, and further recycled to the purification process to purify the zinc sulfate solution. Also, sodium arsenite solution obtained after the reduction of arsenate could be directly used to purify the zinc sulfate solution. Therefore, the technical scheme of alkaline leaching with pressured oxygen, cooling crystallization, arsenate reduction by SO₂ gas, and arsenic trioxide preparation, provides an attractive approach to realize the resource utilization of arsenic-containing cobalt and nickel slag.     

利用低冰镍制备铁酸镍前躯体

以低冰镍为原料,采用草酸盐共沉淀法合成颗粒细小的铁酸镍前躯体 NiFe2(C2O4)3·6H2O。NiCl2?FeCl2?(NH4)2C2O4?H2O体系的热力学研究表明：Ni2+和Fe2+的理论最佳共沉淀pH值为2,2?24C O 对Ni2+、Fe2+离子具有较强的络合作用。在理论研究的基础上,考察沉淀参数对沉淀率和前躯体粒度的影响。结果表明：最佳共沉淀条件为溶液pH=2,反应温度为45°C,(NH4)2C2O4加入量为理论值的1.2倍,PEG400加入量为3%。在此条件下,Ni2+和Fe2+的沉淀率达99.8%,所得前躯体的粒径为1~2 um。XRD和TG?DTA分析表明：所得前躯体为单相置换固溶体,反应过程中镍、铁原子相互取代。     

Corrosion Products Formed on Copper exposed to humid SO2-containing atmospheres

X-ray diffraction analyses have been performed on samples of electrolytic copper (min. 99,9% Cu) exposed to humid atmoshperes at SO₂-supplies of 10 and 100μg SO₂ per cm² surface area per hour (10 and 100 ppm SO₂. respectively). During the SO₂ -exposures copper (II) sulphate (CuSO₄ · 5 H₂O) were the only crystalline phases formed in detectable amounts. Interruption of the SO₂- supply resulted in the formation of copper (I) oxide and antlerite (CuSO₄) · 2Cu (OH)₂. During prolonged exposure brochanite (CuSO₄ · 3Cu(OH)₂) and langite (CuSO₄· 3Cu(OH)₂) and langite (CuSO₄ · Cu(OH)₂ · 2H₂O) were also formed i. E. the Cu:S ratio of the basic copper sulphates increased with time. The formation of antlerite was preceeded by formation of an unidentified intermediate compound, probably a basic copper sulphate with a Cu:S ratio of less than three, and a simultaneous transformation of the copper (II) sulphate and copper (I, II) sulphite formed during the SO₂-exposure.