Adsorption form of flotation reagent on mineral surface
Most flotation agents act on the surface of minerals by adsorption.The adsorption forms of flotation reagents on the mineral surface are as follows:
(1)Molecular adsorption,that is,the agent is adsorbed on the surface of minerals in the form of molecules.Such as the adsorption of neutral oil on the surface of non-polar minerals(graphite,molybdenite,etc.),the adsorption of double xanthate on the surface of sulfide minerals,and the adsorption of certain foaming agents(such as terpineol oil,fatty alcohol,etc.)on the gas-liquid Adsorption of the interface.
(2)Ion adsorption,that is,the agent is adsorbed on the surface of minerals in the form of ions.Such as the adsorption of xanthate on the surface of galena,and the adsorption of carboxylic acid collectors on the surface of fluorite and scheelite.
(3)Ion exchange adsorption refers to the equivalent exchange of a certain ion in the solution with another ion with the same charge sign on the surface of the mineral,which is adsorbed on the surface of the mineral.For example,when Cu2+is used to activate zinc blende,Cu2+is adsorbed on the surface of zinc blende from the solution,and Zn2+on the surface of zinc blende is exchanged and dissolved into the solution.
(4)Electrical adsorption,adsorption by electrostatic force.For example,the adsorption of dodecyl sulfate on the surface of goethite,and the adsorption of dodecylamine on the surface of quartz.
(5)Semi-micelle adsorption.For collectors with long hydrocarbon chains,when the mass fraction in the solution is high,after their molecules or ions are adsorbed on the surface of the mineral,under the action of Van der Waals force,the non-polar groups will associate with each other.This adsorption It is called semimicelle adsorption.For example,when the mass fraction of dodecylamine is high,it can form semimicelle adsorption on the surface of quartz.In some cases,the formation of semimicelle adsorption is beneficial to flotation.The hydrophobicity produced by the collectors forming semi-micelles on the mineral surface is stronger than the hydrophobicity produced by a single collector ion or molecule.But at this time,if the mass fraction of the collector is increased,it is possible to form multilayer adsorption of the collector on the surface of the mineral,which will reduce the hydrophobicity of the surface and reduce the recovery rate.