Method of purifying sodium bromide from waste circuit boards pyrolysis coke

A method for purifying sodium bromide from waste circuit board pyrolysis coke, characterized by the following specific steps:

• (1) carbonization conversion:
• crude bromine salt enriched from waste circuit board smelting ash is mixed with coke separated from waste circuit board pyrolysis residues to form a uniform mixture, the uniform mixture is heated to obtain carbon monoxide and crude sodium bromide, the carbon monoxide is collected and used as raw material of water gas, in which a mass of the coke is 0.1-1.0 kg per kilogram of the crude bromine salt, reaction temperature is 250-450° C., and reaction time is 1.0-2.0 h;
• (2) purification filtration:
• the crude sodium bromide obtained in step (1) is added to distilled water for purification filtration to obtain impurity residues and sodium bromide solution, the impurity residues are centralizedly treated;
• (3) vacuum exsolution:
• the sodium bromide solution obtained in step (2) is treated by vacuum exsolution to obtain sodium bromide crystal and exsolution mother liquor, and the exsolution mother liquor is returned to purification filtration process.