Collecting agent is a flotation agent that changes the hydrophobicity of the mineral surface and makes the floating mineral particles adhere to the bubbles. The most important category to choose is potions. It has two most basic properties: (1) It can be selectively adsorbed on the surface of minerals;
(2) It can improve the hydrophobicity of the mineral surface, making it easier to adhere to the bubbles, thereby improving the floatability of the mineral.
Xanthate is one of the important collectors.
Properties of xanthate
Xanthate is xanthate, whose scientific name is hydrocarbyl dithiocarbonate. It can be regarded as the product of carbonate in which one metal ion is replaced by a hydrocarbyl group and two oxygen atoms are replaced by sulfur atoms. It is generally The formula is R-OCSSMe, such as sodium ethyl xanthate. R in the general formula is often an aliphatic hydrocarbon group CnH2n+1, where n=2~6, and rarely R is an aromatic hydrocarbon group, cycloalkyl group, alkylamino group, etc. Me is often Na(+), K(+), and industrial products are often Na(+). The properties of kaxanthate and sodium xanthate are basically the same, but kaxanate is more stable than sodium xanthate, sodium xanthate is easy to deliquesce, while kaxanate is not deliquescent, and the price of sodium xanthate is lower than that of sodium xanthate. All are easily soluble in water, alcohol and acetone. According to the number of carbon atoms in the R group of xanthate, they are called ethyl sodium xanthate, butyl sodium xanthate, etc.
Usually, methyl xanthate and ethyl xanthate are called low-grade xanthate, and those with butyl and above are called high-grade xanthate. Xanthate is crystalline or powder. Impurities are often yellow-green or orange-red gelatinous with a density of 1.3~1.7 g/cm3. It has a pungent odor and is toxic (medium). Short-chain xanthate is easily soluble in water, soluble in acetone and alcohol, and slightly soluble in ether and petroleum ether. Therefore, the acetone-ether mixed solvent method can be used to recrystallize and purify the xanthate.
Application and storage of xanthate
The collection ability and selectivity of xanthate for various minerals are closely related to the solubility product of its corresponding metal xanthate. Common metal minerals are often divided into three categories based on the solubility product of metal ethyl xanthate: (1) Chalcophilic element minerals: the solubility product of metal ethyl xanthate is less than 4.9×10^-9. Metals that fall into this category include Au, Ag, Hg, Cu, Pb, Sb, Cd, Co, Bi, etc. Xanthate has the strongest ability to collect natural metals (such as Au, Ag, Cu, etc.) and metal sulfide minerals of such elements. (2) Siderophilic element minerals: The solubility product of its metal ethyl xanthate is greater than 4.9×10^-9 but less than 7×10^-2. Metals that fall into this category include Zn, Fe, Mn, etc. Xanthate has a certain ability to collect metal sulfide minerals of such elements, but it is relatively weak. If xanthate is used as the collector, it is easier to achieve flotation separation of metal sulfide minerals that are chalcophile elements and metal sulfide minerals that are siderophile elements. Although the solubility products of ethyl xanthate of cobalt and nickel are less than 10^-1 and they are cuprophilic elements, they often closely symbiosis with iron sulfide minerals and are often flotated together with iron sulfide minerals. (3) Lithophile element minerals: The solubility product of its metal ethyl xanthate is greater than 4.9×10^-2. Metals belonging to this category include Ca, Mg, Ba, etc. Due to the large solubility product of its metal ethyl xanthate, a hydrophobic film cannot be formed on the surface of this type of metal mineral under normal flotation conditions, and xanthate has no collecting effect on this type of metal mineral. Therefore, xanthate is not used as a collector when sorting alkali metal and alkaline earth metal minerals, oxide minerals and silicate minerals. Generally, the solubility product of metal sulfide minerals is smaller than the solubility product of the corresponding metal ethyl xanthate. According to chemical principles, it is impossible for the xanthate anion X(-) to react with the surface of metal sulfide minerals and replace S(2-). Only when the surface of the metal sulfide mineral is slightly oxidized, the S(2-) on the surface of the metal sulfide mineral is replaced by OH(-), SO4(2-), S2O3(2-);, SO3(2-), and after plasma, the metal When the solubility product of xanthate is smaller than the solubility product of the corresponding metal oxide, it is possible for the xanthate anion X(-) to replace the anion corresponding to the metal oxide on the surface of the metal sulfide mineral. Xanthate is often used as a collector for natural metals (such as Au, Ag, Cu, etc.) and metal sulfide minerals in chalcophile and siderophile elements. In order to prevent hydrolysis, decomposition and excessive oxidation of xanthate, xanthate should be stored in airtight containers. Avoid contact with humid air and water, pay attention to waterproofing and moisture-proof, and should not be exposed to the sun or stored for a long time. It should be stored in a cool, dry and ventilated place. The prepared xanthate aqueous solution should not be left for too long, and hot water should not be used to prepare the xanthate aqueous solution. The xanthate aqueous solution is generally used on a shift basis, and the concentration of xanthate preparation for production is usually 5%.
Post time: Oct-10-2024
