A method of recovering bromide from bromine-containing smelting ash

Patent metadata

Field	Value
Publication number	US-2020392000-A1
Application number	US-201916485141-A
Country	US
Kind code	A1
Filing date	Jan 15, 2019
Priority date	Sep 17, 2018
Publication date	Dec 17, 2020
Grant date	—

Abstract

A method of recovering bromide from bromine-containing smelting ash relates to the field of high efficient separation and recovery of bromine by total wet method. It especially relates to the method of high efficiency separation of bromine salt and lead, zinc recovery of circuit board smelting ash by two-step method. It mainly comprising: sub-molten salt leaching, washing, separate Lead and zinc by adjusting the pH of industrial sulfuric acid, membrane separation and concentration, reuse of water, crude bromine salt recovery by evaporation crystallization of bromine salt. Compared with the traditional baking and recycling process of ash, the invention adopts sodium hydroxide submolten salt leaching technology and membrane separation and concentration technology, to reduce the reaction temperature and tailings discharge greatly, which has a good effect of energy saving and emission reduction.

First claim

What is claimed is:

1 . A method of recovering bromide from bromine-containing smelting ash comprising:
(1) leaching by sub-molten salt method: smelting ash containing bromine and sodium hydroxide is leached by sub-molten salt method in a sodium hydroxide system, leaching liquid and residue are obtained; (2) washing: wash the leaching residue obtained in step (1), a solid-to-liquid ratio of leaching residue:water is 1:5 to 1:10 Kg/L, water is at room temperature, washing liquid and washing residue are obtained, the washing residue is collected and treated; (3) separation of lead and zinc: merge the leaching liquid obtained in step (1) with the washing liquid obtained in step (2) to obtain a mixture, a volume ratio of leaching liquid:washing liquid is 1:3 to 3:1, add 98% industrial concentrated sulfuric acid to the mixture until the pH of the mixture reaches 6.5-8, lead-zinc separation residue and lead-zinc separation liquid are obtained; (4) membrane separation concentration: the lead-zinc separation liquid obtained in step (3) is separated and concentrated by reverse osmosis membrane to obtain concentrated solution and water, the water is returned to the washing step (2); (5) evaporation crystallization of bromine salt: the concentrated solution obtained in step (4) is evaporated and crystallized to obtain crude bromine salt; (6) lead separation: lead-zinc separation residue obtained in step (3) is mixed with water, a solid-to-liquid ratio of lead-zinc separation residue:water is 1:1 to 1:2 Kg/L, stir and add 98% concentrated industrial sulfuric acid until pH thereof reaches 4.5 to 6, and filter to get lead sulfate and lead separation solution; (7) evaporative crystallization of zinc: crude zinc sulfate is obtained by evaporation and crystallization of the lead separation solution obtained in step (6);

2 . The method of recovering bromide from bromine-containing smelting ash of claim 1 , wherein,
in step (1), a solid-to-liquid ratio of smelting ash containing bromine:sodium hydroxide system is 1:20 to 1:40 Kg/L, the sodium hydroxide system is a sodium hydroxide solution with a mass concentration of 25 to 45%, a leaching temperature is 140 to 200° C. and leaching time is 2 to 4 hours.

Assignees

• Univ Beijing Technology

Inventors

• Pan Dean
• Wu Yufeng

Classifications

• Y02P10/20

  Recycling · CPC title

• C22B13/045

  Recovery from waste materials · CPC title

• C22B19/30

  from metallic residues or scraps · CPC title

• C22B7/02

  Working-up flue dust · CPC title

• C22B7/008

  by an alkaline or ammoniacal leaching · CPC title