Resourceful treatment method for desulfurization wastewater

The invention belongs to the technical field of wastewater treatment and recycling, and particularly relates to a desulfurization wastewater resourceful treatment method. According to the method, the composite calcium removal agent with specific components is selected in the primary calcium removal process, so that the calcium ions can be removed to the greatest extent under the condition that the concentration of the magnesium ions is basically not reduced in the step, namely, effective separation of the calcium ions and the magnesium ions is realized under the condition that impurity ions are not introduced, the calcium ions can be reduced to 60 mg/L or below, and the content of the magnesium ions can be reduced to 60 mg/L or below. The removal rate of magnesium ions is below 10%; the method comprises the following steps: carrying out secondary calcium removal treatment to further reduce the concentration of calcium ions to below 10mg/L, and finally carrying out nanofiltration salt separation, concentration