Достижения в области переработки и управления отходами

Preparation of Lead, Lead-Alloy and Other Salts from Exhausted Grids of Some Rechargeable Lead Batteries

Abstract

Mahmoud A Rabah1, Maie I El-Gammal2, MS Ibrahim2, Sabah M Abdel Basir3 and Omar M Helmy2

Metals of lead and some lead alloys, lead oxide, nickel and cobalt were recovered from exhausted grids of electrolyte-free rechargeable lead batteries by combining hydrometallurgy and pyrometallurgical method. The spent grids were leached in hot 2 M and 5 M nitric acid. The unleached fraction was heated with sodium carbonate to produce lead oxide. The leachants were analyzed by Inductively coupled plasma mass spectrometry (ICP). Lead was precipitated as hydroxide on cold with ammonia. Nickel and cobalt metals in solution were extracted by solvent extraction using LEWATIT MP 600 ion exchange resin. Metals loaded by the organic phase were stripped by HCl. Metal hydroxides were reduced with ascorbic acid or hydrazine hydrate to ultrafine free metals, Lead alloys were prepared by encapsulating the alloying metal oxide or organic salts in the host lead metal and heated at 800°C. The end products were investigated with Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray fluorescence (XRF), ICP and scanning electron microscope (SEM). Results revealed that the spent grids contain 94.2% lead, aluminium 0.12%, nickel 0.05% and cobalt 0.053%. The particle size of the reduced metals was found in range of 15-60 um, LEWATIT MP 600 ion exchange resin is specific adsorbent for nickel and cobalt. Distribution constant (Kd) value of the stripping step decreased in the order Ni and Co. Lead-Al-Mg alloy was prepared by heat treatment of terminal taps at 500°C. The obtained lead alloys were investigated with EDX and SEM. Lead calcium alloy was homogeneous and contain calcium particles with 5 ums.