Quartz vein gold-bearing ore is mainly composed of quartz, with a content of 50-95%. The content of metal minerals is 0-15%, pyrite is the main sulfide mineral, followed by pyrrhotite and a small amount of galena, chalcopyrite and sphalerite. In addition to quartz, the gangue also includes sericite, plagioclase, muscovite, calcite, orthoclase, etc. Gold minerals are mainly free natural gold and silver-gold ores, mostly in fine-grained and fine-veined pyrite, and a small amount in chalcopyrite and quartz.
The single flotation process is suitable for processing sulfide gold-bearing quartz vein ores with fine gold particles and high floatability, polymetallic gold-bearing sulfide ores and carbon-bearing ores. This vein gold ore beneficiation process first floats gold into copper and lead concentrates, and then extracts gold from these concentrates. It is relatively economical and reasonable for gold ores containing non-ferrous metals in the original ore. It can realize the comprehensive utilization of multiple metals, enrich gold in sulfide minerals as much as possible, and directly discard tailings. However, because it cannot ultimately obtain finished gold, its application range is relatively small, and it often forms a joint process with other beneficiation methods.
The full mud cyanidation separation process is suitable for gold produced in quartz vein ores in a fine or micro-particle dispersed state, and the ore is deeply oxidized and does not contain specific impurities. The gold-containing ore is leached in a cyanide solution, and then activated carbon is used to adsorb the dissolved gold and load the gold, and the carbon is desorbed and electrolyzed to separate and purify the gold mud for smelting. In this process, cyanide is a highly toxic substance and is easy to pollute the environment. At present, low-toxic gold leaching agents can be used to replace cyanide agents for cyanide gold extraction.
The combined gravity separation-cyanidation process is suitable for treating quartz vein gold-containing oxidized ores. In vein gold ore dressing plants, gravity separation is often used as part of the combined gold selection process. In the grinding and classification circuit, a jig or spiral chute is used in conjunction with a shaking table to recover the dissociated coarse-grained monomer gold in advance, which is conducive to the subsequent cyanidation operation and can obtain qualified gold concentrate.
Flotation-concentrate cyanidation process: for treating ores with a close symbiotic relationship between gold and sulfide, xanthate is used as a collector and pine oil as a frother. After flotation, gold concentrate is obtained and then cyanide leaching is performed. This vein gold ore dressing technology is often used to treat quartz vein gold-containing ores and quartz pyrite ores with a close symbiotic relationship between gold and sulfide. Generally, xanthate is used as a collector and pine oil as a frother. The weakly alkaline slurry is floated in the flotation machine to obtain gold concentrate. Then the flotation concentrate is leached by cyanide, the gold is dissolved by cyanide, the complex enters the solution, and then replaced by zinc powder to obtain gold mud, and finally the gold mud is pyrometallurgically smelted to obtain pure gold.
Flotation-roasting-cyanidation process: It is suitable for treating ores containing impurities that are harmful to cyanide. The flotation gold concentrate is first oxidized and roasted, and it is more conducive to the leaching of gold and silver after removing arsenic and sulfur. This vein gold ore beneficiation technology is suitable for treating minerals that are harmful to cyanide with good floatability (containing impurities such as sulfur, iron, arsenic, etc.), and a small amount of gold is combined with such minerals. For flotation concentrates with high arsenic and sulfur content, after the cyanide tailings are flotated, impurities such as sulfur, iron, and arsenic are enriched in the concentrate to become a high-sulfur and high-arsenic concentrate that is difficult to select. When direct cyanide leaching is not possible, the flotation gold concentrate can be first oxidized and roasted to remove arsenic and sulfur. In this way, the roasted sand structure after roasting is loose, which is more conducive to the leaching of gold and silver.
The flotation-gravity separation combined process is mainly based on flotation, which is suitable for ores where gold and sulfides coexist closely and can only be recovered by smelting, as well as gold-bearing quartz vein ores with coarse and uneven distribution. It has a higher recovery rate than a single flotation process. The original ore is separated by flotation to obtain flotation concentrate, and the sulfide part of the flotation tailings often exists in the form of a conjoined body with the gangue. In addition to being wrapped in sulfides as submicroscopic fine particles, gold often exists as coarse and fine monomer gold. The coarse-grained sulfide and gangue conjoined bodies and coarse-grained natural gold in the tailings are difficult to recover by flotation, while gravity separation can better recover this part of gold.
The above are the common beneficiation methods for quartz vein gold-bearing ores. Before formulating a beneficiation plan, it is recommended that you conduct a beneficiation test to determine the ore composition and grade in order to obtain a better beneficiation effect.
