Method for comprehensive recovery of smelting wastewater containing magnesium

摘要

A method for comprehensive recovery of smelting wastewater containing magnesium comprises: adjusting a pH value of acid smelting wastewater containing magnesium sulfate by using an alkaline substance, so as to obtain slurry containing magnesium hydroxide and calcium sulfate, the alkaline substance being an alkaline substance containing calcium; and introducing carbon dioxide gas into the slurry to perform carbonization, and then performing solid-liquid separation to obtain solid slag and magnesium bicarbonate solution. By means of key procedures such as neutralization, precipitation, carbonization and purification, calcium ions are converted into calcium sulfate and a small amount of calcium carbonate that is to be precipitated and recycled for use, and the content of calcium sulfate in the recycled water is reduced, thereby effectively solving the problem of scaling of pipelines, conveying pumps and storage tanks; magnesium ions in the smelting wastewater containing magnesium are converted into a magnesium bicarbonate solution that can be returned for smelting separation, and accordingly, the cyclic utilization of materials in the production process is implemented, and zero emission of wastewater is achieved.