Method for comprehensive recovery of magnesium-containing smelting wastewater

摘要

The present invention discloses a method for comprehensive recovery of magnesium-containing smelting wastewater. The method comprises the steps of adjusting the pH of an acid smelting wastewater containing magnesium sulfate using an alkaline material to obtain a slurry containing magnesium hydroxide and calcium sulfate; And carbonation by passing carbon dioxide gas through the slurry, followed by solid-liquid separation to obtain a solid sludge and magnesium hydrogen carbonate solution, wherein the alkaline material is a calcium-containing alkaline material. This method converts and uses calcium ions into calcium sulfate and a small amount of calcium carbonate through a deterministic process such as neutralization precipitation and carbonation carbonate, so it significantly reduces the content of calcium sulfate in regenerated water, so it scales pipes, transfer pumps, storage tanks, etc. In addition to effectively solving the problem, magnesium ions in the magnesium-containing smelting wastewater can be converted into a magnesium hydrogen carbonate solution and used again for smelting separation, thereby realizing not only circulating use of raw materials in the production process but also zero discharge of wastewater. Therefore, the resource utilization rate of the overall technology line is high, and the economic effect and social benefit are excellent.