Most commonly used anion collectors are weak organic acids (or their salts), which are in a molecular or ionic state depending on the dissociation constant and the media state of the slurry. Action thereof with the mineral surface, generated by the physical adsorption of molecules of the van der Waals force, electrostatic force or adsorption generated electric double layer, most of these agents can form insoluble compounds with an alkaline earth metal and heavy metal ions, may be mineral surface Chemical adsorption and surface chemical reactions occur. According to the existing research, it is considered that the double layer adsorption and chemical adsorption are the main mechanism of action. γ i =2 γ i c i exp [- nF ξ + ¢ ] RT In the middle  γ i — the adsorption density of the species (here, the sulfonate ion); Fe 3+ 2.9 to 3.8 Al 3+ 3.8 ~ 8.4 P b 2+ 6.5 to 12.8 Mn 2+ 8.5 to 9.4 Mg 2+ 10.9 ~ 11.4 Ca 2+ 12 or more. These boundary demarcation pH pH and the formation of hydroxides quite consistent. When the concentration of the collector changes, the above pH boundary also changes accordingly. It can be seen that the mechanism of flotation of quartz after activation by metal ions can be explained by double layer adsorption or chemisorption. Wire Rope,Rigging Equipment,Wire Rope Sling,Lifting Shackles Shandong Shenli Rigging Co.,LTD. , https://www.shenliriggingcn.com
The study of the adsorption of A on the surface of the mineral layer on the surface of the mineral layer on the action of the anion collector and the non-sulfurized ore shows that when the concentration of the anion collector is low, the ions are adsorbed by the electrostatic force, which is called "counter-concentration ion adsorption". At high concentrations, the hydrocarbon chains of the collector ions interact to form a semi-colloidal state called "half micelle adsorption."
Is to sulfonate type collector typical oxide - aluminum oxide adsorbing an example will be described. The adsorption density of sodium dodecyl sulfate on the surface of alumina and the relationship between the potentiostatic potential and the equilibrium concentration. When the concentration of the collector is <5 X 10 -5 mol , the sulfonic acid ions are adsorbed on the alumina surface in a single state; when the concentration is high, the sulfonate The adsorption density of acid ions increases, close to each other, and combines with each other by the attraction between the non-polar end molecules to form a half micelle. At this time, the adsorption density is about one tenth of that of the monolayer. The adsorption density of the collector ions, for example, for sulfonate ions, can be calculated using the Stern-Graham equation:
r i — the radius of the ion (ie, the tared ion);
 c i — the concentration of the solution;
n — the ion price;
Ξ -dynamic potential;
R — gas constant;
F — Faraday constant;
 ¢ — Characteristic adsorption energy level.
 In addition to static electricity, there are so-called specificity of "specific adsorption" is mainly by static electricity, high concentrations occur at low concentrations, and therefore we should consider "specific adsorption bit" ¢. When the semi-micelle is adsorbed, the ¢ is mainly van der Waals force. ¢ per mole of CH 2 group a value of about 2.60 kJ. Specific to the adsorption of sulfonic acid ions, when the concentration is less than 5 × 10 -5 mol / L , ¢ =0 . Concentration of the zeta potential change is about 3 × 10 -4 mo1, equivalent to about one-tenth of a single layer of the cover, is about ¢ 2.93kJ, when all of the single cover, ¢ = 30.98kJ.
 As the concentration increases, the critical micelle concentration ( CMC ) is reached . The critical micelle concentration, if the hydrocarbon chain is longer, the lower the critical concentration of micelles formed, because the hydrocarbon chain length is stronger due to the mutual association. The micelles formed in the aqueous solution have a structure in which the polar group faces outward and the non-polar group is inward, so that the concentration of the agent above CMC is unfavorable for flotation.
B Electrostatic force adsorption and mineral surface electrical anion collectors are important parameters when adsorbed on the mineral surface by electrostatic attraction.
Adsorption mechanism of the electrostatic force, to move the floating potential relationship may be the most obvious goethite. The zero point of goethite is pH = 6.7 . When the pH is < 6.7 , the surface potential is positive. At this time, the anion collectors RSO - 4 and RSO - 3 are adsorbed on the surface of the mineral to capture. Beryl, chromite, garnet and the like often flotation to adjust the surface potential to a positive value, then the anionic collector (sulfonates) flotation.
When the molecular weight of the anion is increased, that is, using a longer hydrocarbon chain collector, the pH range of the flotation is expanded. In addition, the amount of collector is increased, and the pH range of the flotation is also expanded, which may gradually exceed the physical adsorption range, and exhibit a semi-micelle effect.
In addition, if the collector hydrocarbon chain is too short, such as octanoic acid, even if the concentration is high, the flotation recovery rate is still limited. This indicates that the short chain does not have enough interaction force to form the half-micelle adsorption, that is, it is always only the physical adsorption that maintains the electrostatic force.
The electrostatic attraction of the collector anion on the surface of the mineral is disturbed by other anions in the solution and may compete with the collector anion for the position of the electric double layer. For example, at pH < 1.8 , the surface of the quartz is positively charged, but at this point the addition of the anionic collector is still not floating and can be explained by the competition of anions. When the salt is added as 1 x 10 -4 mo1 / L, the medium was adjusted to pH <1.8, the amount of HCI required to join enough of the medium anionic CI - ratio of anionic collector RSO - 3 concentration 1000 times. Since a large amount of CI - occupies the positive charge region of the quartz surface, the RSO - 3 cannot approach the surface for trapping. [next]
 When C is chemically adsorbed on the mineral surface , the collector is chemically adsorbed on the surface of the mineral in addition to physical adsorption by electrostatic force, van der Waals force, etc. In many cases, chemisorption has a decisive influence on flotation.
When more polar groups chemically reactive with the mineral collector effect, chemical adsorption occurs often, e.g., fatty acids and calcium, barium, minerals of iron, arsenic acid, and phosphonic acids containing tin, iron The role of the substance, the action of complex collectors such as hydroxamic acid and amino acid with iron and copper oxides, the action of amine-based cation collectors and copper-containing and zinc minerals. Some less chemically active collectors, such as hydrocarbyl sulfonate hydrocarbyl sulfates, can also undergo chemisorption when the molecular weight is sufficiently large.
The occurrence of chemisorption and some of its laws have been affirmed by a series of tests and theoretical discussions. Measurement of the surface zeta potential of the mineral surface, anionic collector, e.g., oleate and the phosphorus adsorption calcite limestone surface, occurs at pH above the isoelectric point of zero. At this time, the collector ion has the same sign as the surface charge of the mineral, and the negative value of the potential is increased after the adsorption, which is obviously not caused by the simple electrostatic adsorption. For example, calcite oleate surface acting, when pH = 9.6 (isoelectric point above zero), concentration of greater than 3 × 10 -5 mol, the adsorption increases sharply, while the zeta potential changes are more apparent. The explanation for this is the simultaneous adsorption of chemical adsorption and semi-micelle properties.
Many people have determined by direct measurement by infrared spectroscopy that the collector has chemical adsorption on the mineral. Results using infrared spectrometry oleate adsorbed on fluorite, found 5.8 μ m band, is a - COOH group corresponding physical adsorption, and 6.4 μ m and 6.8 μ m band and is - COO - group chemistry Adsorption corresponding. This assay also showed that the pH is low when mainly physical adsorption, via chemical adsorption the pH is high, and the chemisorption behavior of the flotation closely.
The composition of the adsorption layer of fatty acid salt on calcium and iron minerals, extraction and analysis by organic solvent showed that the adsorption is multi-layered, including the formation of collector-mineral metal compound and the adsorption of chemical ions, molecules and polymers. .
The solubility product of the commonly used anion collector with metal ions has been systematically studied, and it is calculated that there is a corresponding relationship between soap formation conditions and flotation behavior.
For some insoluble oxides, it has also been suggested that chemisorption is related to the case where the cation of the mineral surface is slightly dissolved, followed by hydrolysis of the metal ion to form a hydroxy complex. Such as fatty acid chemically adsorbed on the oxides: hematite, when at about pH = 8 and generating related FeOH +; soft adsorbed manganese ore, at pH = 8.5, relating to MnOH +; and adsorbed on the apatite flotation peak, Corresponding to FeOH+ ( pH = 8 ), MnOH+ and CaOH + (pH=10 to 12) .
As for the cationically activated quartz, the effect of the collector is related to the characteristics of the activated cation.
Quartz has a low solubility and no metal ions that can be hydrolyzed. Therefore, when quartz is floated with an anion collector, it is activated by a metal cation. For example, in quartz flotation, when sulfonate 1 × 10 -4 mol / L is used as a collector, the highest recovery of quartz and various activated metal cations when activated with various metal cations ( The pH range of 1 × 10 -4 mol ) is:
Mechanism of action of anion collector and non-sulfurized ore