In the beneficiation process, the lead-zinc ore is mainly based on flotation, and the flotation methods of lead-zinc ore and oxide lead-zinc ore are different according to the optionality of the ore. Below we introduce two kinds of lead-zinc ore flotation processes.

1. Flotation process of lead-zinc sulfide ore
Under normal conditions, the flotation process of lead-zinc sulfide ore mainly includes traditional flotation process and potential regulation flotation process. Among them, the transmission flotation process includes priority flotation, mixed flotation, equal flotation and asynchronous flotation. There are four kinds of crafts.

①Priority flotation process for lead-zinc sulfide ore
Priority flotation of lead-zinc ore usually adopts the method of first suppressing zinc and floating lead, and then activating zinc to obtain the final lead concentrate and zinc concentrate. After the minerals are ground to the particle size requirement, the lead is flotation with strong collector and high alkalinity, and excess lime and xanthate are added to suppress the newly dissociated pyrite under the condition that the pH value of the slurry is >12. The surface of the dissociated galena is protected by xanthate, and then the lead is recovered by preferential flotation; the flotation tailings are activated by copper sulfate, and the zinc sulfide rough concentrate is recovered by butyl xanthate, and refined under high alkali conditions. Coarse concentrate is selected to obtain zinc concentrate; the floating zinc tailings are thickened and then activated with sulfuric acid, and xanthate is used to recover sulfur concentrate.
The priority flotation process of lead-zinc sulfide ore is mainly suitable for separation of ore with simple composition, high grades of lead and zinc in raw ore, and large difference in floatability of lead-zinc minerals, and lead-zinc ore with coarse particle size.

②Mixed flotation process of lead-zinc sulfide ore
Mixed flotation of lead-zinc sulfide ore is to mix and flotation lead-zinc first, and then separate lead and zinc. Under the condition of not adjusting the pH value of the ore pulp, using xanthate or black powder as a collector, the lead sulfide ore and part of the zinc sulfide ore are floated at the same time to obtain a lead-zinc mixed concentrate. The tailings in the flotation process are activated with copper sulfate, and xanthate is used as a collector for mixed flotation to obtain a mixed concentrate of zinc and sulfur, and then separated by lime and cyanide flotation to obtain zinc concentrate and sulfur concentrate.

The mixed flotation process of lead-zinc sulfide ore is suitable for treating lead-zinc ore with small difference in floatability, low grade and useful minerals in aggregate or dense intergrowth.

③ Flotation process such as lead-zinc sulfide ore
The lead-zinc sulfide ore that can be floated is firstly separated from the lead-zinc sulfide with similar floatability, and then the lead-zinc separation is carried out. In the roughing stage, without adding inhibitors, lead, lead-zinc conjoint organisms and some easy-floating zinc ores can be separated, and the selected products can be separated from lead and zinc after regrinding to obtain lead concentrate and zinc concentrate.

Flotation such as sulfide lead-zinc ore is mainly used to process lead-zinc minerals that contain two parts that are easy to float and difficult to float.

④Asynchronous flotation process of lead-zinc sulfide ore
Asynchronous flotation of lead-zinc sulfide ore is different from waiting for flotation to allow all lead to be flotation at one time, and it also allows zinc and sulfur with similar floatability to float at the same time. Asynchronous flotation is to create suitable flotation conditions for galena and sphalerite in different operations step by step, and to float lead and zinc at the same time.

Asynchronous flotation of lead-zinc sulfide ore is suitable for processing fine-grained lead-zinc ore.

⑤Potential-regulated flotation process of lead-zinc sulfide ore
Potential-controlled flotation of lead-zinc ore sulfide is to control the process and even direction of the oxidation-reduction reaction on the surface of sulfide minerals in the slurry system by changing the electrochemical conditions of the flotation system during the flotation process, affecting the surface state and collection of sulfide ores. The product form and stability of the agent on the surface of sulfide ore increase the hydrophilic-hydrophobic properties of the surface of sulfide ore, thereby realizing the selective flotation separation of sulfide ore. By adding the whole dose of lime and combined inhibitor zinc sulfate + sodium sulfite to the ball mill, the selective flotation separation of galena, sphalerite and pyrite is completed in a highly alkaline slurry environment and low oxidation potential.

Potential-regulated flotation process of lead-zinc sulfide ore is suitable for separation of low-grade lead-zinc sulfide ore.

2. Flotation process of lead-zinc oxide ore
Lead-zinc oxide ore has a high oxide content, its performance is relatively fragile, and it is easy to break when mining, and the composition of this kind of minerals is complex, so it is difficult to separate. At present, the common beneficiation process mainly includes sodium oxide sulfide flotation method , Sulfur vulcanization flotation method, flocculation flotation method, heavy flotation combined separation method, etc.

①Sodium oxide sulfidation flotation process of lead-zinc oxide ore
The lead-zinc oxide ore has low floatability, and it is difficult to float the lead-zinc oxide ore with a higher index by using conventional collectors. Usually, sulfide-xanthate flotation and sulfide-amine flotation are used.

Sulfide-xanthate flotation: After the zinc oxide mineral is sulfided by sodium sulfide, copper sulfate is added as an activator, and high-grade xanthate collectors are used for flotation. Sulfide-xanthate flotation of lead-zinc oxide is suitable for processing lead oxide minerals.

Sulfidation-amine flotation: after the zinc oxide mineral is sulfided by sodium sulfide, the fatty amine collector is used for flotation. Sulfide-amine flotation of lead-zinc oxide ore is suitable for treating zinc oxide ore containing easily muddy gangue, but its process is complicated, desliming equipment is needed, and it can only be realized under the condition of a large amount of sulfuric acid cleaning and activation.

② Sulfur vulcanization flotation process of lead-zinc oxide ore
Sulfur vulcanization flotation is to use sulfur powder to vulcanize the lead-zinc oxide ore, and a sulfide film will be formed on the surface of the vulcanized mineral, so as to realize the separation of lead-zinc oxide ore. However, this process can only be realized under high temperature and high pressure conditions, so it is rarely used at present.

③ Flocculation and flotation process of lead-zinc oxide ore
The flocculation flotation of lead-zinc oxide ore involves intensive stirring of the hydrophobic fine-grained minerals with polymer compounds, and then adding collectors for flotation. Flocculation flotation is suitable for the separation of fine-grained lead-zinc oxide ore. However, because the development of polymer flocculants is difficult and costly, it has not been practically applied at present.

④Combined sorting process of heavy flotation and separation of lead-zinc oxide ore
Due to the particularity of ore properties, some lead-zinc oxide ores sometimes adopt gravity separation-flotation combined separation process to achieve the purpose of comprehensive recovery of useful minerals. The denser or magnetic minerals are recovered by gravity or magnetic separation, or the tailings are pre-thrown by gravity. Heavy flotation combined separation is suitable for ores with relatively different densities between metal minerals and gangue minerals or ores with magnetic properties.

The above is the common flotation process of lead-zinc ore. According to the nature of the ore and the degree of oxidation, the flotation process selected is also different. Therefore, it is recommended that the mine owner conduct a beneficiation test and customize a scientific and reasonable flotation process through the test report. The selection process can improve the flotation index and reduce the economic loss.