Exploration Of Mechanism Of Dechroming From Wet-blue Shavings

Adopting the method of combination of acid, alkali, salt and machinery, the chrome shavings are relaxed and dechromed, as a result, the threadlike collagen fibers are prepared. The threadlike collagen fibers prepared are characterized, and the result indicates that the triple helix structure basically keep in good condition, but the partial sites are destroyed, of which the reason is that the collagen fibers are hydrolized by aicds or alki.The effects of the glucose concentration,the temperature of solution and the time for the solubility of Ca(OH)₂, the constitution of lixivium and the pH value of the solution are investigated. The results indicate that, the C6H12O6·Ca(OH)₂ produced by both Ca(OH)₂ and glucose can advance the solubility of Ca(OH)₂ evidently; After decomposition of glucose, it polymerizes to the result that the color of solution turns yellow, at the same time, the solubility of Ca(OH)₂ and the pH value of solution decline.The mechanism of organic acid on the dechroming from chrome shavings is studied in terms of the depolymerization of complex, the replacement of H⁺ and the replacement of organic acid radical anion. It is found that both the replacement of H⁺ and the replacement of organic acid anion take an important part in the course of the dechroming of organic acid.The maximum absorbed wavelength and variation of the pH of the solution of the reaction product of dechroming of oxalic acid and citrate from chrome shavings are chromium oxalic and chromium cirtrate, and the technological conditions of the dechroming with oxalic acid citrate from chrome shavings are determined.After dechroming the dry heat shrinkage temperature of the threadlike collagen fibers is 185℃, and the terminal poit shinkage temperature is 225℃, and eventually, the rate of shinkage is 44%.