In order to realize the resource utilization of residue（white mud） produced by“one step acid method” extracting alumina from fly-ash，the white mud was studied for decarbonization.The roasting decarbonization flotation decarburization of white mud were conducted，the result was indicative that qualified white mud product with less than 2% firing loss could be obtained by roasting decarburization.However，the temperature need to be strictly controlled.The product was usually substandard if not controlled properly.At the same time，the process energy consumption was relatively high.Flotation decarburization could not only obtain qualified white mud，but also recover carbon resources.The influence of different flotation parameters on the decarburization efficiency was studied.The research showed that under the condition of pulp and reagent reaction time of 8 min，flotation time of 10 min，pulp density of 250 g/L，inflating volume of 140 L/h，capture agent（diesel） dosage of 4 kg/t，emulsifier（Tween-80） dosage of 1.5 kg/t，foaming agent（2-octanol） dosage of 750 g/t，firing loss of flotation white mud was 2.14%，and the carbon recovery was 89%，decarbonization efficiency was the best，flotation was the preferred white mud decarbonization method.