| 摘要 |
After a reducing roasting of laterite or garnierite the resulting metallic Ni and Co are extracted with an ammoniacal soln. contg. (NH4)2CO3 and (NH4)2SO4; the soln. is treated with an oxidising gas to convert unsatd. sulphur values into the sulphate form; then boiled to expel free ammonia and to decompose free (NH4)2CO3; most of the Ni is then precipitated in the form of a Ni sulphate-NH4 sulphate complex salt by addn. of H2SO4, H2SO3 or SO2; the precipitate is sepd. from the soln., the dissolved Co and the remaining Ni are precipitated in the form of a mixed Co-Ni sulphide product by adding H2S, (NH4)S, Na2S and NaHS; whilst the precipitated complex salt is dissolved in an aqs. ammoniacal soln. and high-purity Ni (Co =0.005%) is recovered. |
