How to select gold from quartz vein gold ore？

The formation of quartz is usually associated with hydrothermal alteration at medium and low temperatures, in which case gold can be easily enriched to industrial grades. This is what forms the quartz vein gold deposits.

The appearance of quartz vein gold ore is usually grayish yellow and white, and its internal structure is mainly medium and fine grains, with a scattered structure. The ore minerals are mainly chalcopyrite, pyrite, sphalerite, natural gold, and the stone minerals are mainly quartz, calcite, feldspar and so on. Chalcopyrite and pyrite are mostly distributed in quartz veins.

Quartz vein gold ore is very common in nature, and the beneficiation of quartz vein gold ore is of great significance to economic development. The following article will discuss the most suitable beneficiation process for quartz vein gold by analyzing the situation of quartz vein gold beneficiation test.

         A typical quartz vein gold ore is selected as the sample ore. The main useful mineral is gold, followed by small amounts of silver and pyrite, and the main stone mineral is quartz.

         The results of chemical multi-element analysis and phase analysis of pristine quartz vein gold are shown. The main valuable element recovered from the ore was gold at a grade of 0.9 g/t. Phase analysis results show that the quartz vein gold is dominated by bare gold. Other metallic minerals are present in relatively small amounts, mainly pyrite at a grade of 0.1%. Stone minerals are mainly quartz, sericite and sodalite.

1. Single flotation process to treat quartz vein gold ore

         First, a flotation trial is performed to determine the appropriate flotation chemistry system, grind size and flotation time. On this basis, the primary roughing, secondary concentration and secondary cleaning flotation processes were carried out. The final gold concentrate production rate was 0.93%, the grade reached 96.8g/t, and the recovery rate was 95.77%. The processing effect of gold is good, but there is coarse gold sinking phenomenon in the flotation cell, which has a certain influence on the index of gold concentrate.

2. Gravity-flotation process to treat quartz vein gold

        The gravity separation process is a traditional method for the pollution-free recovery of granular gold. But it has the disadvantages of low enrichment rate and small capacity. In the gold processing test of quartz vein gold ore, shaking table separation is performed first, and then the gold concentrate is flotation by flotation process. Finally, the comprehensive grade of concentrate obtained by the combination of gravity method and flotation method is 133.77g/t, the recovery rate is 91.32%, and the tailings loss rate is 6.09%. The test results of gold ore beneficiation show that the combined process of vibrating screen separation and flotation can recover gold better.

3. Nelson mineral processing - gravity separation - flotation process

         Firstly, the grinding fineness test and the Nielsen gravity multiple test are carried out to determine the optimum grinding fineness and the optimum gravity multiple respectively. After the two main factors were determined, the combined testing of beneficiation using Nielsen concentrator, shaking table separation and flotation process began.

         In the tests, the quartz vein gold powder was first processed by Nelson, and the obtained coarse concentrate was then passed through a shaker. In order to reduce the loss of Nelson tailings, flotation of Nelson tailings is carried out. The Nelson Gold Gravity Process recovers coarse-grained gold. The Nelson gravity concentrate yield was 1.19%, the grade was 64.03%, and the recovery rate was 86.58%. The concentrate grade obtained by the vibrating screen separation process was 480.60 g/t with a recovery rate of 83.34%. After flotation of the Nelson tailings, the gold concentrate grade was 11.2 g/t with a recovery rate of 10.97%. Therefore, the overall recovery of the process reached 94.31%.

         1. The single flotation process has a good flotation index, the recovery rate reaches 95.77%, and the concentrate grade is 96.8g/t. It is recommended for quartz vein gold deposits with less mud content and no coarse-grained gold. However, for quartz-veined gold deposits with high mud content and coarse-grained gold like the samples in this paper, the use of a single flotation process would result in lower gold concentrate grades than would be recovered by gravity. Therefore, in this case, a single flotation process is not recommended.

        2. The recovery rate of gold reached 91.32% in the joint test of gravity separation-flotation process, and the concentrate grade was 133.77g/t. The vibrating screen can recover gold better, which is beneficial to reduce the loss of gold in tailings. This method is recommended for small gold processing plants. However, for medium-sized or large-scale gold processing plants, in view of the small processing capacity of the shaker, large floor space, high factory requirements and high investment, it is not recommended to use the gravity separation process.

         3. The recovery rate of gold tested by Nielsen combined with gravity separation and flotation technology reached 94.31%, and the concentrate grade was 480.60g/t. Nelson has a large processing capacity and a small equipment footprint, which can save space in the gold processing plant and prevent crude gold from sinking. Therefore, this process is recommended for quartz vein gold ores with more grainy gold. Through comparative analysis, for the quartz vein gold beneficiation in the test, the processing index of this process is the most ideal.

         Through the beneficiation test of quartz vein gold ore, it can be seen that single flotation, Nelson beneficiation-gravity-flotation process, and gravity-flotation process can recover gold in the raw ore well. However, each of these three processes has its own characteristics. The specific process of quartz vein gold mine also needs to be considered comprehensively according to the nature of the ore, the area of the gold mine beneficiation plant and the investment situation. It is recommended that you find a professional gold ore beneficiation service provider and a gold ore beneficiation equipment manufacturer with laboratory qualifications.