Dissolution of cadmium or zinc in sulphuric acid - using tungsten or molybdenum metal or carbide as catalyst

摘要

Dissolution of Cd, Zn or Cd-Zn alloys in H2SO4 is carried out in the presence of W or Mo metal or their carbides pref. in the form of powder (ca. 20 mu m) in an amt. of 1-3% w.r.t. Cd and/or Zn and pref. at 90-100 degrees C. The additive catalyses dissolution. Pref. the soln. is sepd. from the sedimented additive. If the additive is used in metallic form, the W or Mo passing into soln. is pptd. by adding Fe(III) ions and the ppte. is filtered or centrifuged off. The same additive can be used several times and pref. is reactivated by treatment with HNO3.