Un nouveau procédé de séparation par flottation de la pyrrhotite monoclinique et de la galène

Domaine technique
The present invention relates to a novel process for flotation separation of monoclinic pyrrhotite and galena.

Arrière-plan artistique
Pyrrhotite is a widely distributed iron sulfide mineral that can coexist with many minerals. Due to varying degrees of iron atom deficiency, it not only changes in composition but also deviates in structure; its structure can transform from a hexagonal system to a monoclinic system. This results in different flotation behaviors of different pyrrhotites in solution. As the structure evolves from hexagonal to monoclinic, its floatability gradually improves from poor to good. Therefore, monoclinic pyrrhotite has very good floatability, making its separation from other minerals difficult. The depression of pyrrhotite and its separation from other minerals are regarded as a hot topic and a challenge in the mineral processing field.

Résumé de l'invention
The object of the present invention is to provide a novel process for flotation separation of monoclinic pyrrhotite and galena. By using this process, the flotation recovery of galena can reach over 90%, while that of monoclinic pyrrhotite is below 10%, thereby achieving separation of the two minerals.

The object of the present invention can be achieved by the following measures:

(1) Grinding the ore to a certain particle size;
(2) Adjusting the pulp pH using acetic acid and sodium acetate;
(3) Adding collector and frother to float galena, thereby achieving separation of the two minerals.

Specifically, the following conditions can be adopted:

• Grind the ore to –0.074 mm;
• Use acetic acid and sodium acetate to adjust the pulp pH within the range of 3.6–5.6 and stir for 3–8 minutes;
• The collector used is a xanthate, with a concentration in the pulp of 5×10⁻⁵ mol/L to 2.5×10⁻⁴ mol/L, and after adding the collector, stir for 1–5 minutes;
• The frother used is either ether alcohol or No. 2 oil; the dosage of ether alcohol is 10–15 mg/L, and the dosage of No. 2 oil is 12–25 mg/L; after adding the frother, stir for 1–5 minutes;
• Flotation time is 7–15 minutes.

The advantages of the present invention are: using this process, the flotation recovery of galena can reach over 90%, while that of monoclinic pyrrhotite is below 10%, thus achieving effective separation of the two minerals.

Brief Description of the Drawing

Figure 1 is a schematic flow diagram of the process for separating monoclinic pyrrhotite and galena provided by the present invention.

Exemple 1
The ore was ground to –0.074 mm. The pulp pH was adjusted to 4.0 using acetic acid and sodium acetate and stirred for 5 minutes. The collector, sodium butyl xanthate, was added to achieve a concentration of 2×10⁻⁴ mol/L, and the pulp was stirred for 2 minutes. The frother, butyl ether alcohol, was added at a dosage of 10 mg/L, and the pulp was stirred for 2 minutes. Flotation was carried out for 9 minutes. The flotation separation results are shown in Table 1.

Table 1 Flotation separation results of the mixed ore at pulp pH 4.0

Exemple 2
The ore was ground to –0.074 mm. The pulp pH was adjusted to 4.67 using acetic acid and sodium acetate and stirred for 5 minutes. The collector, sodium butyl xanthate, was added to achieve a concentration of 2×10⁻⁴ mol/L, and the pulp was stirred for 2 minutes. The frother, butyl ether alcohol, was added at a dosage of 10 mg/L, and the pulp was stirred for 2 minutes. Flotation was carried out for 9 minutes. The flotation separation results are shown in Table 2.

Table 2 Flotation separation results of the mixed ore at pulp pH 4.67

Exemple 3
The ore was ground to –0.074 mm. The pulp pH was adjusted to 5.0 using acetic acid and sodium acetate and stirred for 5 minutes. The collector, sodium butyl xanthate, was added to achieve a concentration of 2×10⁻⁴ mol/L, and the pulp was stirred for 2 minutes. The frother, butyl ether alcohol, was added at a dosage of 10 mg/L, and the pulp was stirred for 2 minutes. Flotation was carried out for 9 minutes. The flotation separation results are shown in Table 3.

Table 3 Flotation separation results of the mixed ore at pulp pH 5.0

Exemple 4
The ore was ground to –0.074 mm. The pulp pH was adjusted to 3.6 using acetic acid and sodium acetate and stirred for 5 minutes. The collector, sodium butyl xanthate, was added to achieve a concentration of 2×10⁻⁴ mol/L, and the pulp was stirred for 2 minutes. The frother, ethyl ether alcohol, was added at a dosage of 12 mg/L, and the pulp was stirred for 2 minutes. Flotation was carried out for 9 minutes. The flotation separation results are shown in Table 4.

Tableau 4 Flotation separation results of the mixed ore at pulp pH 3.6