Abstract: It was studied that reducing and dyeing of Vat Olive Green B in a electrochemical system of the ferric sulfate, calcium gluconate and tartaric acid in caustic soda solution. It was discussed that the influence of concentration of each component, temperature and time of reducing and dyeing, voltage and cathode area on dyeing effect. The results shown that the optimum process is the concentration of ferric sulfate 4 g/L, the calcium gluconate 5 g/L, tartaric acid 21 g/L, sodium hydroxide 16 g/L, reducing and dyeing temperature 35 ℃, reducing and dyeing time 80 min, applied voltage 7V, and the cathode area 28 cm2. Compared with the fabric dyed by traditional process, the K/S value of the fabric dyed by the electrochemical system was improved by 7.07%. While the dyeing evenness and the color fastness of the fabric were similar.

Key words: electrochemistry, reduction, vat dyes, dyeing, Fe3+-Ca2+-tartaric acid complexes