Designing paste thickeners for copper flotation tailings, using bed depth scale-up factor

Aim: The paste thickener could increase the water recovery and reduce the environmental impacts in tailings dam. The present work aimed to find the appropriate scale-up factor for bed depth to design paste thickener for copper tailings, using a lab glass cylinder and an operating pilot column. The thickening tests were carried out on the flotation tailing samples obtained from the Sarcheshmeh and Miduk copper mines located in Iran. Based on the industrial conditions, the values of influential parameters for paste thickener used in these experiments were pH=11 and feed solid=10 %. Flocculant type was NF43U and used as 25g/t with dosage of 0.25 g/lit. The unit area of Sarcheshmeh and Miduk paste thickeners were designed as 0.057 and 0.047m2/t/day, respectively. Based on the dry feed rates to each paste thickener as 7920 and 4320 t/day, the thickener's diameters were determined as 23.9 and 16.1 meters which are similar to the actual thickener's diameters (24 and 16 meters), respectively. In addition to unit area, the bed depth is also important in the paste thickeners design. Hence, the ratio of industrial to lab unit bed volume for Sarcheshmeh paste thickener was obtained 75 which was equal to the ratio of industrial to lab bed depth (bed depth scale-up factor exclusively for copper flotation tailings). This procedure was validated by using the Miduk sample. The bed depth in the paste thickeners was determined as 7.5 meters, by using the bed depth scale-up factor which was comparable to the actual bed depth (8 meters). This research confirmed that the bed depth scale-up factor is able to correctly determine the bed depth of industrial paste thickeners for copper tailings.