Collector is a changemineralsurfaceHydrophobicity, makeflOwOfOre grainAdherent to bubblesflotationMedication.The most important flotation reagent.It has two basic properties: (1) it can selectively adsorb on mineral surface;(2) It can improve the hydrophobic degree of mineral surface and make it easy to adhere to bubbles, thus improving the floatability of minerals.[1]
Most collectors are heteropolar organic compounds.For example, xanthates, carboxylic acids, fatty amines, etc.Its molecular structure generally contains two groups: polar group and non-polar group, which have an important impact on the whole molecular flotation performance. The composition and structure of the polar group of the collector determine the chemical properties and dissociation properties of the collector in water.
After dissociation of various collectors in water, the solidophile atoms in polar groups are mainly - S -, - O - and - NH+3.Generally speaking, when the solid atom of the collector is the same as the non-metallic element in the mineral, the collection can occur.
Action mechanism
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The basic mode of collector action is the adsorption of the molecules or ions of the agent at the mineral water interface.It mainly includes molecular adsorption, ion adsorption, semi micellar adsorption and adsorption of reaction products of collectors on mineral surface.
(1) Molecular adsorption.Adsorption of collector molecules dispersed or dissolved in pulp solution on mineral surface.The physical adsorption of non-polar molecules is mainly the adsorption of various hydrocarbon oils;The physical adsorption of polar molecules is mainly the adsorption of undissociated molecules of xanthate, oleic acid and amine collectors at the solid-liquid interface.
(2) Ion adsorption.The adsorption of collector ions in the pulp on the mineral surface, such as the adsorption of xanthate on the surface of galena when pH>5, and the adsorption of oleic acid collectors on calcium containing minerals (fluorite, calcite, scheelite, etc.).
(3) Semimicellar adsorption.When the concentration of the collector is high enough, the non-polar group of the long hydrocarbon chain collector will be adsorbed on the mineral surface and associate to form two-dimensional micelles, which is called "semi micellar adsorption".For example, when using dodecyl amine acetate to float quartz, with the increase of dodecyl amine concentration, the adsorption of dodecyl amine ions increases, forming semi micelles on the mineral surface.
(4) Adsorption of reaction products of collector on mineral surface.A series of reactions may occur when collectors interact with other ions or mineral surface in the pulp, and some products in the reaction are adsorbed on the mineral surface.If xanthate acts on the surface of sulphide minerals or oxidizes in pulp, it can generate hydrocarbon thiocarbonate (ROCOS -) and xanthate (ROCSSO -), which can be adsorbed on the surface of oxidized minerals and sulphide minerals respectively to generate collection.
category
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According to the molecular structure of reagents, collectors can be divided into two categories: polar collectors and non-polar collectors.Polar collectors can be divided into ionic type and non-ionic type according to the dissociation properties of reagents in aqueous solution.Ionic collectors are divided into anionic, cationic andAmphoteric collector；According to the chemical composition of polar groups, anionic collectors can be further divided into thio compounds, namely mercapto collectors and hydrocarbon oxygen containing acids, namely hydroxyl collectors;Cationic collectors are amine collectors;Non polar collectors are hydrocarbon oils belonging to organic compounds.(See table)
Common sulfide ore collectors include xanthateXanthate derivative、Black drug、baiyao、Benzothiazole mercaptan、Benzimidazole mercaptan、Benzoxazole mercaptanEtc.
Collect oxidized iron ore, scheelite and wolframite
Mines, etc
Non ionic
Ester collector
Thiamine esters: ROCSNHR ′
Xanthates: ROCSSR ′
Sulfur nitrogen esters: R2NCSSR ′
Collect metal sulfide minerals
Bisulfides
Collector
Double yellow drugs: (ROCSS) 2
Double black drugs: [(RO) 2POS] 2
Collect and precipitate metal powder and sulfide
Non-polar collector
Hydrocarbon oil
Hydrocarbon oil CnH2n+2
CnH2n
Collect non-polar minerals and use them as auxiliary collectors
Note: R and R 'in the table are different hydrocarbon radicals;M is Na, K; NHfourOr H, and the rest are element symbols.
Usage selection
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The role of collector on mineral surface isphysical adsorption、chemical adsorptionAnd surface chemical reaction.CollectoradsorbentIt is closely related to mineral flotation behavior.Within a certain concentration range of collectormedicamentconcentrationIncrease, adsorption capacity increases, flotationrate of recoverySignificant increase;concentrationAfter reaching the equivalent value, the recovery rate decreases with the increase of concentration and adsorption capacity;When the concentration of collector is too high, the adsorption capacity can continue to increase, but the flotation recovery rate will not increase, or even decline.Therefore, the amount of collector should be correctly controlled in the flotation process to obtain the best benefit.[2]
