Difficulties in gold ore dressing and gold ore dressing technology of Carlin type gold ore

15311826613

Welcome to consult Xinhai - customized mineral processing plan

Xinhai can provide you with mineral processing tests, mineral processing process and mineral processing equipment selection, mineral processing plant scheme design and construction drawing design; provide mining mineral processing equipment; provide mineral processing plant construction and equipment installation as well as mine management and operation services.

Consultation 153-1182-6613

15311826613

Click to add WeChat

Get product price

WeChat ID has been copied, add friends, and get manufacturer quotations!

Among all kinds of gold ores, Carlin-type gold ore is a fine disseminated gold deposit mainly produced in carbonate rocks. The gold grade of this type of gold ore is relatively low, the mineralization scale is large, and the gold particle size is fine. Its main gangue minerals include quartz, calcite, barite, kaolinite, etc. It is a gold ore that is difficult to recover. If the harmful elements such as arsenic and mercury are not handled properly, it is easy to cause environmental pollution. Next, we will take you to understand the difficulties of Carlin-type gold ore beneficiation and its beneficiation process.

Difficulties in Carlin-type gold ore selection

The ore body of Carlin-type gold ore is relatively complex, with high arsenic, carbon and mercury content in the ore, and fine gold ore distribution. The main difficulties in its selection are as follows:

✦ The lower gold ore particle size increases the difficulty of grinding the mineral;

✦ The carbon in the ore may adsorb the gold dissolved in the precious liquid, making it difficult to separate;

✦ Toxic minerals such as arsenic and mercury in the ore hinder the recovery of gold.

From the above points, it can be seen that it is difficult to achieve the ideal separation effect by using a simple gold ore dressing process. Compared with ordinary sulfide gold ore, the Carlin type gold ore dressing process is more complicated.

Carlin type gold ore dressing process

According to the properties and characteristics of the ore, after crushing and grinding, the Carlin type gold ore dressing process mainly includes flotation, biological oxidation or roasting, cyanide leaching, etc. Next, we will discuss in detail the dressing process of carbon-containing gold ore, arsenic-containing gold ore, silicon-sulfide gold ore and silicon-containing difficult-to-select gold ore.

1. Carbon-containing gold ore dressing process

The organic carbon in carbon-containing ores comes from early marine algae. The organic carbon is converted into kerogen, which is subjected to hydrothermal action during the gold mineralization period to form active pyroasphalt. Compared with coconut shell charcoal commonly used in carbon-in-slurry and carbon-in-leaching methods, the carbon in the mineral has a higher adsorption capacity for dissolved gold, resulting in the inability of the gold minerals in the ore to remain normally in the cyanide noble solution. This phenomenon is usually called "gold robbery".

In order to avoid the "gold robbery" phenomenon, this type of gold ore dressing process first needs to be neutralized by oxidation (such as roasting, oxidation, and biological oxidation), and then then use cyanide leaching to recover gold to obtain better gold ore dressing effect.

In addition, since carbon minerals have good floatability, pine oil or kerosene can also be used as a collector to flotate and separate carbon minerals, which can greatly reduce the carbon content in the ore.

2. Arsenic-containing gold ore dressing process

The arsenic in this type of gold ore may react with the surface of pyrite to form arsenopyrite, which makes it unable to react with the collector, so it is difficult to recover the gold in it. Since the gold particle size in Carlin-type gold ore is very fine, and the carrier mineral of gold is mainly pyrite, which is closely associated with arsenopyrite, it will be more difficult to flotation separation.

For arsenic gold ore dressing, it is necessary to aerate the ore before flotation to promote oxidation of the ore to remove arsenic minerals on the surface of arsenopyrite, and at the same time use a strong collector, such as BK903G, BK302A or MA, to improve the flotation effect of fine gold and gold-bearing minerals. In addition, copper sulfate, lead nitrate and other activators can be appropriately added to improve the floatability of gold carrier minerals.

3. Silicon-sulfide gold ore dressing process

Since pyrite and silicon can wrap gold particles, it may cause difficult selection characteristics. Cyanide may react with sulfide first rather than gold, affecting the gold recovery rate. Therefore, this type of gold ore can be recovered by high-pressure leaching or roasting.

4. Silicon-containing refractory gold ore dressing process

When gold particles are wrapped by silicon with poor water permeability, the gold particles are difficult to be directly recovered. This phenomenon is called "silicon lock". Compared with carbon-containing and sulfide-containing ores, the dressing process of this type of gold ore is relatively simple. The gold recovery rate can be improved by appropriately increasing the grinding fineness in the grinding stage, and then flotation or leaching is performed to recover gold minerals.

The above are the difficulties in Carlin-type gold ore dressing and its dressing process. The composition of gold ore minerals in different regions is also different, so the dressing process is also different. Before selecting the Carlin-type gold ore dressing process, it is necessary to conduct a dressing test, determine the gold ore dressing process according to the test result report, and use a scientific and reasonable method to obtain the ideal gold recovery index.