Feasibility of recovering metals from associated slags
The associated mineral ore accompanying Valuable Metal Compounds (VMC) have been usually treated in a smelting furnace ,such as Blast Furnace, Reverberatory, Blowing Furnace, hence the VMC were mostly concentrated into the molten associated slags and separated from liquid metals. So the associated slags become an important man-made resources (Table I), in which the VMC exist dispersively in various mineral phases with fine grain size1–4. Due to complex mineralogy and very fine mineral dissemination of the associated slags, it is difficult to recovery the VMC from the slags by metallurgical or mineral process conventionally . Based on several case studies in laboratory and practices in pilot plant on the associated slags , there occur a feasibility to recovery the VMC from the slags by a new process-Selective Precipitation Technique (SPT) on which three continuous steps are involved (in Figure 1).
Kinetics of non-isothermal precipitation process of the perovskite phase in CaO-TiO2-SiO2-Al2O3-MgO system
Kinetics of non-isothermal precipitate process and crystal growth of perovskite (CaO·TiO2) phase in CaO-TiO2-SiO2-Al2O3-MgO system were studied. The experimental results show that the relative volume fraction can be described by the equation given by Matusita et al. and the experiential expression of average crystal radius was obtained. The particle coarsening in non-isothermal process has important effects on the crystal growth of perovskite phase.
Failure analysis for poor solderability of Au surface of PCB
Nonwetting is one of the common problems and is always rejected in electronic assemblies. ENIG pads of a PCBA exhibited nonwetting after lead-free reflow soldering. With the aid of stereomicroscope, SEM&EDS and XRF, a series of analysis was performed. And after visual inspection, surface and cross section analysis, thickness measurement and solderability test, it can be inferred that oxidation of plating surface was the main reason for nonwetting, and corrosion in Ni plating caused an adverse impact on solderalibity.