การกำจัดเศษหนังเจียนที่มีโครเมียมปนด้วยวิธีการเผาและกำจัดเถ้าโดยทำให้เป็นก้อนด้วยซีเมนต์ / อภิสิทธิ์ พันธุ์พฤกษ์ = The treatment of leather waste containing chromium by incineration and ash solidification with cement / Apisit Punpruek
This experiment was carried out by burning the leather waste at various fixed temperatures of 400℃, 800℃ and 1,200℃, in order to study mass balance of chromium and the ash physical and chemical properties. A study to solidify the ash by using Portland cement or a mixture of Portland cement and lime (1:1 ) as binders were also carried out. The conclusion is : The leather waste had a Cr+3 concentration of 31.1 mg/g, There was no Cr+6. Its leachate contained 20.02 mg/l of chromium which higher than the 5 mg/l standard, the leather waste was then classified as a hazardous waste and a suitable treatment should be done. From burning the leather waste at 400℃, 800℃ and 1,200℃, most of the total of chromium was found in the bottom ash. And Cr+6 was also found เท the ash. The most appropriate time for burning was 15 minutes in every temperature of incineration where the mass of the ash was almost constant and it also generated less Cr+6. By using the Ministry’s leaching method, the ash from burning at 400℃, 800℃ and 1,200℃ contained 45.72, 89.21 and 410.39 mg/l of Cr respectively. They were still classified as hazardous waste. Portland cement was found to be the most appropriate binder. The optimum mixing ratios of the ash burning at 400℃, 800℃, 1,200℃ and Portland cement were 1:3, 1:4 and 1:5 respectively. The solified products had met the standards promulgated by the Ministry of Industry. The optimum water/cement ratio were 0.5 which helped to improve the mixture workability. The estimated cost for treatment and disposal of the leather waste by burning at 400℃, 800℃ and 1,200℃ were 4,891, 4,699 and 5,654 baht/ton respectively. The most suitable method for treatment and disposal of the waste were burning at 800℃ and then solidified the ash by Portland cement.
