The invention discloses a process for jointly preparing
cadmium sulfide from lead-
zinc smelting slag, which comprises the following steps: firstly, carrying out neutral leaching on the
lead smelting slag, carrying out filter-pressing
solid-liquid separation on leached ore pulp to obtain a leaching solution A and lead-rich
slag, returning the lead-rich slag to a
lead smelting system to recover lead,
grinding the
zinc smelting slag through wet ball milling, adding caustic soda flakes into the ore pulp to carry out alkaline leaching, and carrying out
solid-liquid separation on the leached ore pulp to obtain
cadmium sulfide; carrying out filter pressing
solid-liquid separation on the obtained leaching ore pulp to obtain a leaching solution B and
zinc-rich slag, returning the zinc-rich slag to a
lead smelting system to recover valuable metals such as zinc, silver and gold, carrying out mixed reaction on the leaching solution B and the leaching solution A, carrying out filter pressing after the reaction to obtain a
cadmium sulfide product and a cadmium-settled solution, returning part of the cadmium-settled solution to the
zinc smelting slag to carry out alkaline leaching, and recycling the cadmium-settled solution.
Sodium salt crystallization products and condensate water are produced partially through evaporative
crystallization. According to the method,
cadmium sulfide is produced through
combined treatment of neutral leaching and alkaline leaching, so that elements such as lead, zinc, gold and silver in the two materials are effectively enriched, the enrichment rate of lead and zinc and the
recovery rate of cadmium are high, and the process is short.