Kinetics of nickel leaching from roasting-dissolving residue of spent catalyst with sulfuric acid

Sulfuric acid leaching process was applied to extract nickel from roasting-dissolving residue of a spent catalyst, the effect of different parameters on nickel extraction was investigated by leaching experiments, and the leaching kinetics of nickel was analyzed. The experimental results indicate that the effects of particle size and sulfuric acid concentration on the nickel extraction are remarkable; the effect of reaction temperature is mild; while the effect of stirring speed in the range of 400-1 200 r/min is negligible. Decreasing particle size or increasing sulfuric acid concentration and reaction temperature, the nickel extraction efficiency is improved. 93.5% of nickel in residue is extracted under suitable leaching conditions, including particle size （0.074-0.100） mm, sulfuric acid concentration 30% （mass fraction）, temperature 80 ~C, reaction time 180 min, mass ratio of liquid to solid 10 and stirring speed 800 r/min. The leaching kinetics analyses shows that the reaction rate of leaching process is controlled by diffusion through the product layer, and the calculated activation energy of 15.8 kJ/mol is characteristic for a diffusion controlled process.

光老化条件下印泥色料变化规律研究

研究印泥色料在人为老化条件下的变化不仅能为样本不充分或无比对样本条件下的印文形成时间检验提供可能，还可为可疑文件是否经过人为老化提供判定依据。选用亚信牌、津玉牌等4种不同品牌的印泥，复印纸、信稿纸等3种纸张分别制作了印泥印文的样本，利用UV500-Ⅱ型紫外分析仪对印泥色料进行光老化，利用薄层扫描仪对印泥色料溶解提取率的变化规律进行研究。

热老化条件下印泥色料变化规律的研究

研究印泥色料在人为老化条件下的变化不仅能为样本不充分或无比对样本条件下的印文形成时间检验提供可能，还可为可疑文件是否经过人为老化提供判定依据。本文选用亚信牌、津玉牌等4种不同品牌的印泥，复印纸和信稿纸两种纸张，分别制作了印泥印文的样本，利用HS-100型恒温恒湿试验箱对印泥色料进行热老化，利用薄层扫描仪对印泥色料溶解提取率的变化规律进行了研究。