The addition of ferrous sulfate as a depressant for Ca-bearing minerals such as calcite and fluorite during scheelite flotation was investigated to recover scheelite from tungsten mine tailings, using Hallimond-tube flotation tests, zeta-potential measurement and Fourier-transform infrared (FT-IR) analyses. The flotation tests indicate that the selectivity of scheelite recovery was the largest over calcite and fluorite under the following conditions: 0.5 g sample, 50 g/ton AF65, 1 × 10⁻³ M sodium oleate, 1200 g/ton SF2 (sodium silicate and ferrous sulfate) depressant with the 8:2 ratio of sodium silicate and ferrous sulfate, 50 mL/min air injection rate, 5 min flotation time, and pH 8. The selectivity of scheelite flotation increased when the amount of SF2 depressant addition increased to 1200 g/ton, but it decreased by adding 1400 g/ton SF2, which would result from the precipitation of iron components. In the zeta potential results, the zeta potentials of scheelite with the collector show similar results regardless of the addition of SF2, while the change of zeta potentials of calcite and fluorite by adding NaO collector diminished when SF2 was added. In FT-IR analyses, the spectrum of NaO in scheelite results was observed regardless of the addition of SF2, while the spectra of NaO in calcite and fluorite results disappeared when SF2 was added. These results suggest that the addition of SF2 prevents the adsorption of NaO on the surface of calcite and fluorite. Therefore, the addition of SF2 could enhance the selectivity of scheelite flotation over calcite and fluorite.

中文翻译：

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硫酸亚铁对方解石和萤石上白钨矿选择性浮选的影响

利用哈里蒙德管浮选法，Zeta电位测量法和傅里叶变换红外光谱（FT- IR）分析。浮选试验表明，在以下条件下，白钨矿回收的选择性超过方解石和萤石，选择性最大：0.5 g样品，50 g /吨AF65、1×10 ^-3M油酸钠，1200 g / ton SF2（硅酸钠和硫酸亚铁）抑制剂，硅酸钠和硫酸亚铁的比例为8：2，空气注入速率为50 mL / min，浮选时间为5 min，pH为8。 SF2抑制剂的添加量增加到1200 g / ton时，白钨矿浮选增加，但SF2的添加量为1400 g / ton时，白钨矿浮选减少，这是由于铁成分的沉淀所致。在ζ电位结果中，无论添加SF 2，带捕收剂的白钨矿的ζ电位显示出相似的结果，而当添加SF 2时，通过添加NaO捕收剂，方解石和萤石的ζ电位的变化减小。在FT-IR分析中，无论添加了SF2，都观察到了白钨矿结果中的NaO光谱，加入SF2后方解石和萤石中NaO的光谱消失。这些结果表明，SF 2的添加阻止了NaO在方解石和萤石表面上的吸附。因此，添加SF2可以提高白钨矿浮选对方解石和萤石的选择性。