Recovering fluorite from lead‑zinc tailings

The Shaodong Lead‑Zinc Mine in Hunan recovers fluorite from its lead‑zinc tailings. The mine processes more than 200 tonnes of raw ore per day. The deposit belongs to the medium‑low temperature hydrothermal fissure fluorite‑quartz vein type lead‑zinc polymetallic deposit. The concentrator uses a lead‑zinc selective flotation process to recover lead and zinc metals. The annual tailings discharge is 60,000–63,000 tonnes. The mineral composition of the tailings is relatively simple, mainly consisting of quartz, slate chips, and fluorite, with small amounts of calcite, feldspar, barite, muscovite, etc. The content of the main minerals (quartz, slate chips, and fluorite) is about 90%. The mass fractions of the main elements and the mineral composition of the tailings are shown in Table 4‑47 and Table 4‑48, respectively.

Table 4‑47 Mass fractions of main elements in tailings (%)

Table 4‑48 Mineral composition of tailings (%)

The Changsha Nonferrous Metals Research Institute conducted research on the utilisation of the tailings after lead‑zinc separation. Based on the characteristics of the raw material, a branch flotation process (see Figure 4‑32) was adopted to recover fluorite. The test results showed that the obtained fluorite concentrate has a grade of 98.78% CaF₂, 0.46% CaCO₃, and 0.64% SiO₂, meeting the requirements for chemical‑grade fluorite. Based on an annual tailings output of 60,000 tonnes, more than 4,500 tonnes of fluorite can be recovered each year.

Figure 4‑32 Branch flotation process for recovering fluorite from tailings

Figure 4-32 Branch flotation process