Case study of mine water treatment

1、 Overview

The original treatment process for mine water in a coal mine in Shaanxi province was "grid+pre settling regulating tank+magnetic loading sedimentation". The effluent from the sedimentation tank was discharged after reaching the standard, but the salinity and some ion indicators of the effluent could not meet the relevant reuse standards.

2、 Characteristics of raw water quality

(1) The mass concentration of TDS reaches 3950mg/L, with high mineralization. Its salt components are mainly Na+, Ca2+, sulfate, acid carbonate, and chloride;

(2) The hardness is high, with a total hardness of 512mg/L measured by (CaCO3), of which the calcium hardness (measured by CaCO3) is 285mg/L, belonging to the category of extremely hard water;

(3) The raw water treated by grid, pre sedimentation regulating tank, and magnetic loading sedimentation has a clear surface, low turbidity, and low chromaticity;

(4) Mine water, as groundwater, after pre-treatment, has low organic matter content and low microbial content;

(5) The mass concentration of HCO-3 is 199 mg/L, with a high alkalinity.

3、 Process flow

4、 Running effect

The average inflow of the system is 280m3/h, the water production is 200m3/h, and the water production meets the design requirements; The system recovery rate is 71.4%, which is better than the design value (66.7%). The water temperature of the mine water is stable at around 27 ℃, with a TDS mass concentration of 3700-4000mg/L and a hardness of 450-500mg/L. The incoming water quality fluctuates little. Regular testing data shows that since the system was put into use, the TDS and ion content of the produced water have far exceeded the design requirements, and the water quality of the produced water is stable, with a desalination rate of 98%, meeting the requirements for reuse.