With the continuous growth of the global economy, the demand for lead and zinc metals is increasing day by day. However, the reserves of high-grade lead-zinc ore are decreasing year by year. At present, the efficient recycling of complex and difficult-to-select lead-zinc ore is a top priority. In recent years, there have been new developments in the research of lead-zinc ore dressing technology. Let's take a look.
Crushing and grinding operations have always been a major obstacle to energy conservation and consumption reduction in the concentrator, because of its high energy consumption, large steel consumption, and the existence of dust pollution and noise pollution. It has always been a difficult problem.
The traditional lead-zinc ore crushing and grinding process, based on the principle of more crushing and less grinding, mostly adopts a two-stage crushing + ball milling process, or a three-stage (or four-stage) crushing + ball milling process.
However, these traditional crushing and grinding processes can no longer meet the current crushing and grinding needs of poor and fine ores. In recent years, new crushing and grinding processes have been tried, including: crushing + rod mill + ball mill, crushing + semi-autogenous grinding + ball mill, crushing + semi-autogenous grinding + vertical mill, crushing + high-pressure roller mill + ball mill, etc. The application of these processes has made the crushing and grinding process more and more diversified, reducing energy consumption and steel consumption while also improving dust and noise pollution.
(1) Flotation of lead-zinc sulfide ore
The structure of sulfide lead-zinc ore is complex, and useful minerals and associated minerals are closely embedded. Commonly used flotation processes include priority flotation process, full mixed flotation process, partial mixed flotation process, equal floatable flotation process, asynchronous flotation process and branched series flotation process.
In recent years, some new project experiences have provided some new ideas for the flotation of sulfide lead-zinc ore, such as:
Silver-containing low-grade lead-zinc ore can adopt the process of priority flotation of lead and then flotation of zinc;
Complex sulfur and oxygen mixed lead-zinc ore, adopt the process of mixed flotation of sulfide ore and oxide ore;
High sulfur and high iron lead-zinc ore, adopt the flotation process of lead-sulfur mixed flotation - lead-sulfur separation - tailings and then zinc selection;
Silver-lead-zinc ore adopts silver-lead rapid flotation - asynchronous enhanced reselection - coarse concentrate re-grinding and selection process, assisted by the use of lead efficient collector BK906, which solves the problem of the same mineral affecting the mineral processing index due to the difference in floatability.
(2) Flotation of oxidized lead-zinc ore
Single oxidized lead-zinc ore is very rare, and it is generally a complex deposit containing both oxidized lead-zinc ore and sulfide lead-zinc ore. For this complex ore deposit, the new progress made in recent years is to adopt the staged flotation of flotation sulfide ore first and then flotation oxide ore. The main process flow is: lead sulfide-lead oxide-zinc sulfide-zinc oxide flotation in sequence, lead sulfide-zinc sulfide-lead oxide-zinc oxide flotation in sequence.
For the problem that some lead oxide minerals are easy to float, which will cause high lead content in zinc sulfide flotation, the solution is: use lead sulfide and lead oxide for simultaneous flotation, that is, lead sulfide + lead oxide-zinc sulfide-zinc oxide flotation in sequence.
(3) Gravity separation-flotation combined process
Gravity separation is often used as an auxiliary method for pre-selection of waste and treatment of middlings to improve the efficiency of mineral processing. For high-mud type sulfur-oxygen mixed lead-zinc ore, a combined recovery process of pre-de-sludge-mud gravity separation to recover zinc oxide-sulfur first and then oxygen flotation to recover lead and zinc can be adopted.
(4) Magnetic separation-flotation combined process
When the lead-zinc ore contains magnetic minerals such as sphalerite, pyrrhotite, and magnetite, the introduction of magnetic separation to separate magnetic minerals in the flotation process can improve the separation effect of the target mineral.
(5) Sorting-flotation combined process
Low-grade lead-zinc ore can be pre-selected and discarded using intelligent waste sorting equipment to improve the grade of the selected ore and reduce the energy consumption of grinding.
(6) Metallurgical combined process
For complex and difficult-to-select ores, conventional mineral processing technology is difficult to produce qualified concentrate products, or it is impossible to fully recycle resources. In this case, metallurgical combined processes such as biometallurgy and pyrometallurgy can be used to improve the resource recovery rate.
The above are some new developments in lead-zinc ore dressing technology. With the deepening of research on lean and fine minerals and the gradual accumulation of relevant project cases, I believe we will learn more experience from them and make greater progress in the future, making lead-zinc ore dressing simpler, allowing mining companies to obtain greater profits, and making better use of mineral resources for us.
