Method for stabilizing fluorides and arsenic in soil

A method for stabilizing fluorides and arsenic in a soil, comprising the following steps:

• step 1, adding a calcium-containing compound to the soil contaminated by the fluorides and the arsenic, stirring uniformly, and standing for curing to obtain a first mixture;
• step 2, adding an iron-containing compound to the first mixture obtained in step 1, stirring uniformly, and standing for curing to obtain a second mixture;
• and
• step 3, adding water to the second mixture obtained in step 2, optionally adding a pH adjusting agent to adjust a gravimetric water content to 30%-40%, and standing for curing;
• wherein
• the calcium-containing compound is at least one selected from the group consisting of calcium chloride and calcium nitrate;
• the iron-containing compound is at least one selected from the group consisting of ferric sulfate, ferrous sulfate, ferric chloride, and iron oxide;
• the pH adjusting agent is at least one selected from the group consisting of calcium oxide, calcium hydroxide, and magnesium hydroxide;
• an amount of the calcium-containing compound is 0.5%-3% of a weight of the soil contaminated by the fluorides and the arsenic;
• an amount of the iron-containing compound is 0.5%-3% of the weight of the soil contaminated by the fluorides and the arsenic;
• the calcium-containing compound and the iron-containing compound have a weight ratio of 3:1 to 1:3;
• an amount of the pH adjusting agent is 0.1%-1% of the weight of the soil contaminated by the fluorides and the arsenic;
• the curing in step 1 lasts for 0.5-1.5 h;
• the curing in step 2 lasts for 0.5-1.5 h;
• and the curing in step 3 lasts for 3-6 days;
• the soil contaminated by the fluorides and the arsenic is an acid soil at a pH value of 4.5-6.5.