High-hardness metallurgical waste water reuse pretreatment method

The invention discloses a high-hardness metallurgical waste water reuse pretreatment method. Treatment is carried out by an adjusting tank, a raw water pump, a reaction tank, a flocculation tank, a sedimentation tank and a clean water tank. The high-hardness metallurgical waste water reuse pretreatment method comprises the treatment steps of: carrying out aeration oxidation on ferrous ions; then adding 30% of sodium hydroxide to regulate pH into a range of 10 to 12; precipitating out part of heavy metal ions; generating hydroxide by calcium salt and magnesium salt in water; then adding sodium carbonate solution with mass concentration of 10%; performing a replacement reaction of calcium-magnesium hydroxide and Na2CO3 to generate CaCO3 and MgCO3 precipitates so as to fulfill the aim of softening and purifying metallurgical waste water. The method disclosed by the invention is high in treatment effect and obvious in effect, effectively solves the problem of bottleneck of difficulty of the high-hardness metallur