Is mineral processing difficult? This in-depth guide explains the core concepts clearly.

Gravity separation, also known as gravity concentration, is a mineral processing method. It separates mineral particles by density based on their density differences, as particles are subjected to varying gravity, fluid force and other mechanical forces in a moving medium. This method is widely used for the separation of ferrous metals, non-ferrous metals, rare metals and coal.

Magnetic separation is a mineral processing method that separates different minerals by virtue of their magnetic differences in an inhomogeneous magnetic field. It is mostly applied to the separation of ferrous metals and rare metals. It can also remove iron impurities from non-metallic mineral raw materials, purify industrial and domestic water, and recover magnetite from heavy-medium coal separation systems.

Electric separation is a physical mineral processing method that sorts minerals and materials based on their differences in electrical properties. It can be applied to the separation of non-ferrous metal ores, rare metal ores, ferrous metal ores (iron, manganese, chromium), as well as non-metallic ores including coal powder, diamond, graphite, asbestos, kaolin and talc.

Flotation, also known as froth flotation, is a mineral separation process that separates minerals from pulp by virtue of bubble buoyancy based on differences in the physicochemical properties of mineral surfaces. It is a concentration process to float solid minerals out of aqueous suspensions (commonly referred to as ore pulp), and a selective separation process occurring at the gas-liquid-solid three-phase interface.

As the most widely used mineral processing method, flotation is applicable to nearly all types of ores. It is adopted for the separation of sulfide minerals such as gold ore, silver ore, galena, sphalerite, chalcopyrite, chalcocite and molybdenite, pentlandite, as well as oxide minerals including malachite, cerussite, smithsonite, hemimorphite, hematite, cassiterite, wolframite, ilmenite, beryl, spodumene, rare earth minerals and uranium ore.

Chemical mineral processing is a separation method that uses chemical or physicochemical techniques to extract and recover valuable components from raw ore or middlings, based on the differences in chemical properties between valuable minerals and gangue minerals. It is an effective approach for processing low-grade, fine-grained and complex refractory mineral materials, as well as removing impurities from difficult-to-treat rough concentrates.

Its basic procedures include roasting, leaching of mineral materials, solid-liquid separation, leachate purification and production of final products. This method features strong adaptability and excellent separation performance, yet it entails relatively high production costs.

Sorting is a mineral processing method. It takes advantage of the differences in ores' optical properties, electrical conductivity, magnetism, radioactivity, as well as their reflection and absorption characteristics under irradiation of various rays (such as gamma rays, neutron rays, beta rays, X-rays, ultraviolet rays, infrared rays and radio waves). Particles arranged in a single layer or line are detected one by one. The acquired signals are amplified and analyzed, and then actuators including manual operation, electromagnetic baffles or high-pressure air are used to separate valuable ores from gangue (waste rock).

This method is applied to the separation of lump and granular materials. It is commonly used for pre-concentration, roughing and cleaning of ores. At present, sorting is adopted to process ferrous metals, non-ferrous metals, rare metals, precious metals, non-metallic ores, radioactive ores, coal, building materials, seeds, food and other materials.

Microbial mineral processing, also known as bacterial mineral processing, mainly uses microorganisms such as iron-oxidizing bacteria, sulfur-oxidizing bacteria and silicate bacteria to remove iron, sulfur, silicon and other substances from minerals. Iron-oxidizing bacteria can oxidize iron, sulfur-oxidizing bacteria can oxidize sulfur, and silicate bacteria can remove silicon from bauxite through decomposition. Besides desulfurization, deironing and desiliconization, this method is also applied to recover copper, uranium, cobalt, manganese, gold and other metals.

Combined force field mineral processing is a mineral separation method that integrates magnetic field, gravity field, van der Waals force, electrostatic force, hydrophobic interaction and flotation. It applies two or more separation principles simultaneously. The main techniques include magnetic fluid separation, air dense medium fluidized bed separation, magnetic agglomeration separation, oil agglomeration separation, magnetic-flotation machine separation, flotation-gravity separation, magnetic-gravity-flotation separation and cyclone flotation.

Special mineral processing refers to mineral processing methods other than gravity separation, magnetic separation, electric separation, flotation, chemical mineral processing, sorting, microbial mineral processing and combined force field mineral processing, as well as their combined technologies.

Major special mineral processing techniques include electrochemically controlled flotation, flash flotation, selective flocculation separation, agglomeration separation, carrier flotation, microbubble flotation, friction-and-bounce separation, eddy current separation, surface flotation, oil separation and aerosol flotation.