Patent ID: 11858822
Assignee: BEIJING UNIVERSITY OF TECHNOLOGY
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  Y | IPC C

Claim 0:
1. A method of separating and recovering bromine from a circuit board incineration ash by a two-step process:
(1) a first alkali leaching process comprising: placing the circuit board incineration ash in a sodium hydroxide solution, filtering the solution of sodium hydroxide containing the circuit board incineration ash to obtain a first leaching residue and a first leaching solution;
(2) a secondary alkali leaching process comprising: adding water to the first leaching residue obtained in step (1), and filtering to obtain a secondary leaching residue and a secondary leaching solution;
(3) a lead and zinc removal process comprising: combining the first leaching solution obtained in step (1) and the secondary leaching solution obtained in step (2) to obtain a combined leaching solution, a mass ratio of the first leaching solution to the secondary leaching solution is 1:3-3:1, adding 98% industrial concentrated sulfuric acid to the combined leaching solution until a pH of the combined leaching solution reaches 6.5-8, filtering the combined leaching solution to obtain a lead-zinc removal residue and a lead-zinc removal solution;
(4) a bromide evaporation and crystallization process comprising: conducting evaporation and crystallization of the lead-zinc removal solution obtained in step (3), to obtain a crude bromide;
(5) a lead separation process comprising: adding the lead-zinc removal residue obtained in step (3) into water to produce a solid-liquid ratio of the lead-zinc removal residue and water of 1:1-1:2 Kg/L, adding 98% industrial concentrated sulfuric acid while stirring until the pH reaches 4.5-6; filtering to obtain lead sulfate and a lead separation solution;
(6) a zinc evaporation and crystallization process comprising: conducting evaporation and crystallization of the lead separation solution obtained in step (5), to obtain a crude zinc sulfate.