微波溶样原子吸收光谱法测定石油添加剂中的钙、

用微波消解技术对石油添加剂进行样品前处理,原子吸收光谱测定其中的钙、镁含量,并与压力消解、干法灰化处理试样进行了对比试验。试验表明,应用微波消解技术对石油添加剂进行样品预处理,方法快速、准确,能满足快速分析的要求。     

用原子吸收法间接测定电厂水中的痕量氯离子

介绍了火焰原子吸收光谱法间接测定电厂高纯水中的痕量氯离子的方法。该法采用ＡｇＣｌ沉淀,测定剩余Ａｇ间接求出氯离子含量,方法的相对标准偏差２．３￣８．６％,上率在９４￣１０３％,灵敏度为０．０２９ｍｇ／Ｌ。     

Structure–function relationship during the early and long-term hydration of one-part alkali-activated slag

Understanding the mechanisms controlling the early (fresh) and long-term (hardened) hydration of one-part alkali-activated slags (AAS) is key to extend their use as low CO₂ substitutes for ordinary Portland cement (OPC). Their “just add water” use makes them easier and less hazardous to manipulate than the more studied two-part ones. This is due to the absence of liquid alkaline activators, which are environmentally and energy demanding. In this work, numerous experimental techniques have been linked to obtain a comprehensive physico-chemical characterization of a one-part AAS activated with Na₂CO₃ and Ca(OH)₂ powders at several water to solid ratios (w/s). Calorimetry and pH/conductivity measurements describe the functioning of the activators immediately after contact with water. Early reactivity is characterized through in situ X-ray powder diffraction (XRPD) and small amplitude oscillatory shear (SAOS) rheology, which reveal a rapid precipitation of nanometric hydration products (nano-C-A-S-H), which results in a continuous increase in the paste cohesivity until setting. Moreover, SAOS shows that rejuvenating the paste by means of shearing (performed externally to the rheometer in this study) is enough to restore the initial cohesion (i.e., workability) for long time spans until setting occurs. The long-term hydration is characterized by ex situ XRPD on aged AAS pastes, in parallel with mechanical testing on AAS mortar. A correlation can be observed between the amount of nano-C-A-S-H and the increase in compressive strength. Overall, this formulation shows satisfactory fresh and solid properties, demonstrating suitability for low- and normal-strength applications.