There are many types of vein gold ore, mainly including 5 types, namely, gold-bearing quartz vein or gold-bearing pyrite vein type, gold-bearing pyrite altered granite type, gold-bearing polymetallic sulfide ore vein type, gold-bearing oxide ores in British vein type and gold-bearing tungsten-arsenic ores in British vein type.
Different types of vein gold mines have different beneficiation techniques due to their different ore properties. Common vein gold beneficiation technologies mainly include five processes, namely: single flotation process, all-slime cyanidation process, and different combined beneficiation processes composed of gravity separation, flotation and cyanidation processes. The five beneficiation methods of vein gold ore are described in detail below.
The single-vein gold flotation process is suitable for the treatment of sulfide gold-bearing quartz vein ore with fine gold particles and high floatability, polymetallic gold-bearing sulfide ore and carbon (graphite) ore, etc.
This vein gold beneficiation process firstly process gold into copper and lead concentrates through flotation, and then extracts gold from these concentrates. It is more economical and reasonable for gold ore containing non-ferrous metals in the raw ore. By comprehensive utilization, gold can be enriched into sulfide minerals as much as possible, and tailings can be directly discarded, but because it cannot finally obtain finished gold, the application range is relatively small, and it often forms a combined process with other beneficiation methods.
Gold is produced in the quartz vein ore in a fine-grained or fine-grained dispersed state. The ore is deeply oxidized and does not contain copper, arsenic, antimony, bismuth and carbon. This kind of vein gold ore is suitable for the all-slime cyanidation process.
The gold-bearing ore is leached in the cyanide solution, and then activated carbon is used to directly adsorb the dissolved gold-carrying gold from the pulp, and the carbon desorption electrolysis gold mud is directly separated, purified and smelted. In this vein gold beneficiation technology, cyanide is a highly toxic substance, which is easy to result in environment pollution. At present, low-toxic gold leaching agent can be used to replace cyanide agent for gold extraction.
Generally, the combined gravity separation-cyanidation process is suitable for the process of quartz vein gold-bearing oxide ores. In vein gold beneficiation plants, gravity separation is mostly used as part of the combined gold beneficiation process. In the grinding and classifying circuit, a jig or a spiral chute is used in conjunction with a shaker to recover the dissociated coarse-grained single gold in advance, so as to facilitate the subsequent cyanidation operation and obtain qualified gold concentrate.
In order to improve the return on investment, for different properties of vein gold ores, the combined beneficiation process of flotation process and other processes can sometimes achieve more impressive results.
1. Flotation - concentrate cyanidation process
This vein gold beneficiation technology is often used to process quartz vein gold-bearing ores and quartz pyrite ores with close relationship between gold and sulfide. Generally, xanthate is used as collector, pine alcohol oil is used as foaming agent, and weak alkaline pulp is flotated in flotation machine to obtain gold concentrate. Then the flotation concentrate is cyanided and leached, the gold is dissolved by cyanide, the complex enters the solution, and then replaced with zinc powder to obtain gold mud, and finally the gold mud is pyro-smelted to obtain pure gold.
2. Flotation-roasting-cyanidation process
This vein gold beneficiation technology is suitable for processing minerals with good floatability that are harmful to cyanidation (containing impurities such as sulfur, iron, arsenic, etc.), and a small amount of gold is combined with such minerals. For the flotation concentrate with high arsenic and sulfur content, after the cyanide tailings are flotated, impurities such as sulfur, iron, and arsenic are enriched into the concentrate to become a refractory high-sulfur and high-arsenic concentrate, which cannot be directly cyanide. During chemical leaching, the flotation gold concentrate can be oxidized and roasted first to remove arsenic and sulfur, so that the calcined sand has a loose structure after roasting, which is more conducive to the leaching of gold and silver.
This vein gold beneficiation technology is mainly based on flotation, which is suitable for ores with close symbiosis of gold and sulfide and can only be recovered by smelting method. A single flotation process will achieve higher recovery rates.
The flotation concentrate is obtained from the raw ore by flotation, and the sulfide part in the flotation tailings often exists in the form of conjoined gangue. In addition to being encapsulated in sulfide by submicroscopic fine particles, gold often exists as coarse-grained and fine-grained single gold. Coarse-grained sulfide and gangue conjoined bodies and coarse-grained natural gold in tailings are difficult to recover by flotation, but gravity can better recover this part of gold.
The gold ore resources are very precious. In order to separate the vein gold ore more reasonably, it is recommended to conduct a beneficiation test first, comprehensively analyze the properties of the ore, and obtain a scientific beneficiation test report, so as to judge which vein gold beneficiation technology is better. Only by comprehensive consideration of the actual situation, investment and other factors of the gold ore dressing plant, can we determine the proper solution and achieve an ideal return on investment.
