The so-called non-cyanide flotation is not multi-metal cyanide as inhibitors when sulphide ore flotation separation. As described above, the cyanide (sodium cyanide and potassium cyanide) are highly toxic agents, as sphalerite and pyrite inhibitor, resulting in water containing cyanide tailings, caused severe environmental pollution. It is common to purify tailings water and wastewater, such as adding bleach. Economically, cyanide is more expensive. In addition, cyanide dissolves precious metals such as gold and silver . Therefore, when cyanide is used for ore containing precious metals such as gold and silver, it is not suitable for comprehensive recovery. Therefore, it is generally emphasized at home and abroad that little or no cyanide is used.
At present, in the domestic flotation of metal sulfide ore, in order to find cyanide substitutes, to achieve cyanide-free flotation process, or to minimize the amount of cyanide, did a lot of experimental research work, and achieved certain results, some flotation The plant has achieved a cyanide-free flotation process.
Most of the experimental studies used sodium sulfite (H 2 SO 3 ) sulfur disulfide (SO 2 ) sodium sulfite and sodium thiosulfate instead of cyanide to suppress sphalerite and iron sulfide. Toxic agents such small, no dissolution of gold, silver and other precious metals, but they are easily suppressed through activation of sphalerite, weak inhibition of the copper minerals, and even activation, beneficial copper? Zinc separation. The main disadvantage is that the inhibition is not strong in cyanide, the action of the agent is easy to disappear, and the amount and use conditions are difficult to control.
In addition, the following methods can be substituted for cyanide.
1. ZnSO 4 +Na 2 CO 3 (or sodium sulfide) inhibits sphalerite and pyrite, which is often used for zinc- lead and lead-lead when lead- zinc is separated.
2, P 2 S 5 + NaOH (also known as Knox method NoKes), under the conditions of PH = 8 ~ 11, for the separation and flotation of molybdenum and sulfide ore, inhibit copper, lead, zinc, iron sulfide.
3. Potassium manganate (K 2 MnO 4 ) and potassium permanganate (KMnO 4 ) can selectively inhibit pyrite at pH=7.5-9.
Domestically, the use of cyanide-free flotation has achieved better results in factories and mines. It can be seen that cyanide-free flotation is also a good indicator for selection. There are still many examples in this area, which are not introduced here.
Domestically used factories with non-cyanide flotation to achieve better results
Serial number | Factory name | Ore type | Process method | index |
1 | Fankou lead-zinc mine | vulcanization Lead-zinc mine | Na2CO3+ZnSO4 replaces cyanide, zinc-suppressed lead | Similar to the separation index of Pb-Zn obtained using cyanide (about 100 g/ton) |
2 | Xiangxi lead-zinc mine | Copper, lead and zinc Sulfide ore | Na2S2O3+FeSO4 in lead-free copper in acidic medium | Better than the index of cyanidation |
3 | Bayi Copper Mine | Copper zinc Sulfide ore | Na2SO3+Na2S replaces cyanide zinc-suppressing copper | Copper and zinc separation index is better than cyanide flotation |
4 | Yinshan Lead-Zinc Mine | vulcanization Lead-zinc mine | Using the "equal floatable" process, completely without cyanide, using zinc and zinc sulphate | Similar to the indicator of adding cyanide |
5 | Pengxian Copper Mine | Copper zinc sulfide | Reform the production process, that is, direct direct flotation to coarse concentrate re-grinding priority flotation, mixed flotation zinc and sulfur separation process, reduce the amount of collector when copper is selected, without cyanide, copper and zinc sulfur Separation | The new process increases the copper concentrate grade by 1%; the recovery rate by 1.5%; the zinc recovery by 1%; and the sulfur recovery by 2%. |
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