| 초록 |
Various operating parameters, such as roasting temperature, time, acid concentration and role of additives were studied. Addition of moisture, during pugging, helped in the formation of insoluble ferric hydroxy sulphate that maintains the equilibrium of SOJS03 partial pressure. The double stage roasting improved the nickel extraction over the single stage isothermal roasting of the material at 700°C. An extraction of 85% nickel with 2-3% iron could be achieved at a temperature of 700°C when roasted for 15 rains, 25 wt% sulphuric acid and 20 wt% moisture in two stages. The nickel extraction was improved a further 8-10% by the addition of alkali and alkaline earth metal salts. The role of additives during roasting was also introduced.
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