The alkalescent condition reduces the mass concentration of iron ions and fastens the nitration reaction of ammonia nitrogen, and leads to the concentration of nitrate.

• 偏碱性条件使铁离子质量浓度降低，同时促进了氨氮硝化反应进行，使矿井水中硝酸盐和亚硝酸盐质量浓度增加。