Study On Removal Of Chrome In Gelatin Extracted From Leather Ccrap

China is one of the world recognized leather producing countries, annual output more than 200 million tons, total world output 1/4. According to reports, in the traditional tanning process, the wet salt per ton of paper produced only make about 20% of the finished leather, have to produce over 600 kg of solid waste. The main components of solid wastes containing chromium waste collagen, gelatin in the boil during the course of chromium ions into the gelatin products of use. The traditional process using the first alkalized and then acidified last brewed in the process, a considerable part of the chromium ion is not isolated collagen system, so chrome gelatin products 2mg/kg not meet the requirements of industrial grade. Even the level of 25mg/kg feed is also difficult to achieve. Therefore, gelatin production process improvements, so that the products low chrome or chrome and chrome recycling is particularly important, and in line with China on the Solid Waste is not only harmless but also resources to the processing requirements.We use the first method of acidification realkalization on processing of chrome attract shavings. Impacting on the efficiency of the process to optimize the factors that determine the optimal conditions, to minimize the content of chromium products, improve the quality of gelatin.The first step is the acidification process, the impact of factors: the selection of the best acid, acid dosage, heating temperature and reaction time study, acidification experiments to determine the optimum operating conditions. The use of orthogonal experiment to find out acidification chrome shavings the best experimental conditions: oxalic acid dosage 4mL/g, temperature 100℃, reaction time is 180 minutes. In control conditions, the chromium removal rate was 75.1%.The second step is alkali treatment process, the main factors: the selection of the best base, base dosage, heating temperature and reaction time were optimized to obtain better conditions of alkaline treatment: gelatin extracted using alkaline treatment MgO The optimum solution conditions: reaction temperature 80℃, 8% MgO dosage, reaction time 6h, water 1000mL. Under optimum conditions, the chromium content can be reduced to 2mg/kg or less.The third step is to Extraction of gelatin process. Using vacuum distillation techniques to put glue solution after alkali treatment, at this stage, the main factors: pH value, mixing time, temperature, etc., has used single-factor test and experiment, to explore optimization, and this stage to determine the optimum conditions of pH 12, reaction temperature is 100℃, mixing time 15 minutes, the reaction time is 2 h. In optimum conditions, the mentioned rate of 76.2% gel.The fourth stage is the stage of chrome sludge treatment sludge generated by the analysis of chromium, at this stage, through the distillation section of chrome sludge for extraction, the chromium mud extracted from the collagen peptides, and ultimately the extraction rate can be raised collagen to 96.8%.Using the first method of acidification of alkaline processing of chrome shavings, is a convenient, practical and effective approach. Studies have shown that this method can effectively reduce chromium content in gelatin, to improve the yield of gelatin can be said for the production of chrome shavings in the use of low chrome gelatin processing, provides a new way of thinking and methods.