The invention relates to the technical field of brine
resource utilization, and discloses a method and device for preparing
sodium bromide from
potassium salt old brine, after the old brine is pretreated,
bromide ions in the old brine are oxidized into elemental
bromine in an electrolytic bath, and the old brine circulates to a flowing
electrode capacitance deionization device in the
oxidation process to remove
chloride ions; the method comprises the following steps: dissolving and extracting an oxidized
bromine simple substance, reacting with a
sodium-containing solution, adding
activated carbon into a reaction solution, concentrating and evaporating the solution to
dryness, adding desalted water, leaching, filtering, and concentrating and
drying a
sodium bromide filtrate to obtain a
sodium bromide product. According to the method, electrooxidation and extraction processes are used for
potassium salt old
halogen bromine extraction for the first time, an electrooxidation method is coupled with an existing extraction method, excellent bromine extraction efficiency is achieved, and green and environment-friendly processes are achieved. And the problems of low efficiency,
chlorine and acid use risks and environmental risks in the current old brine acidification oxidation
reaction system can be solved, and the possibility of later industrialization can be realized.