PAN-S分光光度法测定钢铁中的镍

在pH6～ 8范围内 ,PAN -S与Ni(Ⅱ )形成 1∶1的红色络合物 ,最大吸收峰在 5 35nm ,镍量在 0～ 2 5 μg/2 5ml符合比尔定律 ,摩尔吸光系数为 2 .84× 10 4。掩蔽干扰离子后 ,可以直接测定钢铁中的镍。     

工业煮炉水中氢氧化钠和磷酸三钠的测定

结合实践提出使用双指示剂法测定工业煮炉水中氢氧化钠和磷酸三钠浓度。     

神经网络方法用于镧系离子结构/氟化物、氢氧化物溶度积关联研究

用函数连接型神经网络（FLN）方法,以Ln3＋离子的半径、电负性、4f电子数及周期因子q（本文自定义）为参数,对调系氟化物LnF3和氢氧化物Ln（OH）3的溶度积进行非线性建模,取得了满意的结果．同时给出了两个系列目前尚缺的值,     

含金矿石中金的提取条件的探讨

本研究了氰化法提金过程中加入NaOH进行除砷预处理,从而使浸金时间缩短,浸取率提高。实验表明了采用此种方法提金的最佳条件为：浸金时间20h,浸取率可达95％,PH为9-10。     

碱激发剂对镍渣基地聚物砂浆力学性能的影响

以工业固废镍渣为原料,采用机械力化学制备单组分镍渣基地聚物。研究碱激发剂种类和碱掺量对镍渣基地聚物砂浆抗压强度的影响规律,结合XRD、SEM及EDS等试验对水化产物进行表征。结果表明：当碱激发剂为复掺Na₂SiO₃/Na₂CO₃,w_Na2O=6.5%时,单组分镍渣基地聚物28 d抗压强度可达68.96 MPa。单掺NaOH对镍渣活性激发效果有限,单掺Na₂SiO₃和复掺Na₂SiO₃/Na₂CO₃激发效果显著,单掺Na₂SiO₃和复掺Na₂SiO₃/Na₂CO₃不能使地聚物的矿物组成发生较大改变,但可以显著提高反应体系中凝胶产物的生成量,改善地聚物微观结构的致密程度。     

铝及铝合金直接化学镀镍前处理工艺研究

对不同型号的铝基体前处理中的活化工序进行了对比研究,筛选出了最适宜的前处理工艺,提出了直接化学镀镍的预处理方法,取得了较好的效果。其特点在于无浸锌层,能简化工序,改善生产环境。     

镍价格的主要影响因素及其未来价格走势分析

镍是重要的战略性矿产。研究影响镍价格的各种因素及预测未来价格走势,对于更好地了解国际镍市场,并提出应对措施是非常必要的。本文在系统收集供需形势、供应安全、市场变化、价格走势等文献资料基础上,应用Eviews软件,以协整分析为主要手段,从供需角度入手,分析不锈钢产量（镍的主要消费领域）与LME镍年均价格、LME镍库存与价格、LME镍现货结算价与国内上海物贸镍均价的关系,并结合诸如印尼禁矿等多种突发、偶发的不确定因素,深入分析影响镍价格的主要因素,对镍价格未来走势进行初步分析。结果表明,需求因素（不锈钢产量）与价格具有长期互动关系,短期内关系不明显;库存短期内具有调节价格的作用,而长期内价格变化带动库存变化。国内价格受国际价格左右,我国对镍的定价依然缺乏话语权;镍价格受主要因素影响的同时,偶然、突发等不确定因素会对镍价格造成短时间冲击;镍价格在2015年下半年还会保持上升态势,在2~3年后,价格趋于合理,2025年左右,中国镍消费将达到顶点,此后,中国需求因素对镍价格的影响将削弱。     

Ettringite and thaumasite: A chemical route for their removal from cementious artefacts

The present paper reports a new method for converting ettringite and thaumasite in non-expansible and insoluble phases, for its application in the restoration of concrete artefacts subjected to deterioration through sulphate attack. The salts were synthesized by different processes and, after characterization by means of XRD, FT-IR and optical microscopy, were treated with a series of chemicals in order to induce their decomposition. In particular, different solutions containing barium nitrate, barium hydroxide and ammonium oxalate were used to achieve the complete transformation of both phases in barite, witherite, scarbroite and whewellite. Barium hydroxide seemed to be the most appropriate reactant because the others could give rise to efflorescence within the pores of the mortars by leaving free nitrate or sulphate ions inside the materials. The experimental technique was also tested on two concrete samples collected from the bell-tower of St. Nicholas’ Cathedral in Nicosia (Sicily) with encouraging results.     

基于Keggin型杂多酸与咪唑镍配合物的超分子组装

以Keggin型杂多酸（α-SiW12O404）-和咪唑镍配离子[Ni（im6）]2＋为结构基元,合成了一种新的有机-无机杂化材料[Ni（im）62]（α-SiW12O40）.3H2O（1）,并用单晶结构分析、元素分析和红外分析法对其结构进行了表征.另外,用热重分析法和变温X射线粉末衍射法研究了该化合物的热性质.阳离子[Ni（im）62]＋和阴离子（α-SiW12O404）-通过氢键和静电作用等超分子作用力连接形成二维层状结构.     

The efficiency of chloride extraction from archaeological iron objects using deoxygenated alkaline solutions

Abstract

Chloride-contaminated archaeological iron is unstable and problematic to store and display within museum collections. Reducing its chloride ion content using aqueous desalination followed by storage in controlled relative humidity offers one treatment option. This study reports a quantitative assessment of chloride extraction by aqueous deoxygenated alkaline desalination solutions from 120 individual archaeological iron nails. The three treatment methods comprised alkaline sulphite solution (0.1 M NaOH/0.05 M Na₂SO₃) at room temperature and at 60°C and sodium hydroxide solution (0.1 M) deoxygenated using a nitrogen gas positive pressure system at room temperature. Chloride extraction was monitored using a specific ion meter. The nails were digested after treatment to measure their residual chloride content. A wide range of extraction patterns emerged, with the majority of individual treatments extracting 60–99% of the chloride present. Residual chloride levels for 87% of the objects fell below 1000 ppm and 42% were below 200 ppm. Although no treatment extracted 100% of the chloride in the object, alkaline desalination produced very significant reductions in chloride content. The impact of this on future corrosion of the objects is discussed. This quantitative and statistically viable assessment of deoxygenated desalination treatments provides evidence to support their use in conservation practice, which will impact on procedures for the preservation and management of archaeological heritage.