containing 2.0 eq /L of hydrofluoric acid and 2.0 eq /L of nitric acid, and the concentration, the recovery rate and the discharge amount of the desalted solution of hydrofluoric acid and nitric acid, the amount of additional drugs and other changes in the law, the results in Table 1.

As can be seen from Table 1, when KOH concentration exceeds 1.14eq /L, hydrofluoric acid can be recovered, when the KOH concentration increases, the recovery of hydrofluoric acid concentration and recovery rate increased significantly, KOH concentration is higher, Of the hydrofluoric acid, nitric acid, the less the amount of added, reducing the cost of recovery. As can be seen from the number 6, when the use of flake KOH and neutralization, the highest recovery of hydrofluoric acid, reaching 92.5%) the same experiment was carried out using 10 L of waste acid containing hydrofluoric acid of 1.5 eq /L and nitric acid of 2.5 eq /L, and the results are shown in Table 2.

As can be seen from Table 2, when KOH concentration exceeds 1.56eq /L, hydrofluoric acid can be recovered, KOH concentration increases, the recovery of hydrofluoric acid is also increased, while the reuse of hydrofluoric acid, nitric acid supplementation decreased, with the same trend.

The same experiment was carried out using 10 L of waste acid containing hydrofluoric acid of 1.0 eq /L and nitric acid of 3.0 eq /L.

As can be seen from Table 3, when the KOH concentration exceeds 2.48 eq /L, hydrofluoric acid can be recovered, the higher the KOH concentration, the higher the recovery of hydrofluoric acid, hydrofluoric acid, And the trend is the same as in Table 1.