How to Treat Antimony-bearing Gold Ores?

Easy-to-treat gold ores are usually treated by conventional cyanidation gold extraction process for gold processing. However, there are fewer and fewer easy-to-select gold ores and more difficult-to-process gold ores, which refer to those gold ores that are difficult to achieve a satisfactory gold leaching rate by conventional cyanidation gold extraction process. These gold ores due to the complexity of the constituent minerals and the different states of the gold endowment, the treatment method is not the same, there is no universal treatment process.

According to the characteristics of the nature of the ore, many antimony-bearing gold ores contain not only gold and antimony metal minerals, but also rich in gold ores with high mud content, high degree of oxidation, and leaching of micro-fine particles. Therefore, the recovery of gold mainly considers the recovery of these gold-bearing minerals and the comprehensive recovery of valuable antimony ores to a greater extent. Most Chinese mineral processing plants use antimony arsenic gold and sulfur mixed flotation process program, and the mixed concentrate is directly produced as gold concentrate. However, the antimony content in the gold concentrate is low, the antimony cannot be priced when the product is sold, and the comprehensive utilization rate of resources is low. Meanwhile, the antimony concentration in the gold concentrate leads to a low grade of gold concentrate. In order to obtain high antimony concentrate, antimony sulfur arsenic needs to be further separated from the mixed concentrate, but the separation is difficult and the effect is poor. Then, how to deal with antimony-bearing gold ore?

Antimony-bearing Gold Ores Beneficiation Method

The main beneficiation methods of antimony-bearing gold ores are flotation, pre-treatment, and enhanced leaching methods.

Antimony Gold Flotation

Antimony-bearing gold ore flotation method is generally used in the case that the carrier mineral of gold is not antimony ore, and this method can realize the separation of antimony minerals and sulfur-arsenic gold-carrying minerals, and antimony concentrate can be obtained. The cost is relatively low, but the operation is difficult, not only to ensure the antimony gold ore index but also to minimize the gold being entrapped. Antimony gold ore flotation method can be divided into two kinds mixed flotation method and preferential flotation method.

1. Antimony gold mixed flotation

The mixed flotation process is relatively simple, but sulfur, arsenic, and other flotation gold-bearing minerals are difficult to inhibit, resulting in sulfur, arsenic, and other minerals mixed into the antimony concentrate, affecting the quality of antimony concentrate, also resulting in the loss of antimony concentrate gold.

2. Antimony gold priority flotation

Priority flotation method can be divided into arsenic, sulfur, and other gold-bearing minerals priority flotation and antimony priority flotation two processes. However, in the process of arsenic and sulfur priority flotation, some antimony minerals with good floatability will be floated together, resulting in a greater loss of antimony in the gold concentrate. Meanwhile, in the next step of antimony flotation, a large amount of acid will be added to reduce the pH value, which will increase the investment cost and is not friendly to the environment. Therefore, most antimony gold flotation plants tend to use a preferential antimony flotation process, and the key to this process is the efficient collection of antimony minerals and the effective suppression of gold-bearing minerals such as arsenic and sulfur.

Antimony Gold Ore Pretreatment

When the grade of antimony in the raw ore is low and has no recovery value or when gold is present in the antimony ore, it is difficult to eliminate the effect of antimony by flotation. In order to improve the cyanide leaching environment of antimony-containing gold ores, pretreatment can be carried out by physical or chemical means before leaching to realize efficient leaching of gold. The common pretreatment methods for antimony gold ore mainly include roasting and chemical alkali leaching.

1. Roasting method

Roasting is a common method for the oxidative pretreatment of antimony-containing gold ore. Through roasting, the physical structure of the ore changes, producing loose and porous roasted sand. At the same time, pyroxene is transformed into antimony-containing oxides in the oxidizing high-temperature atmosphere to eliminate the unfavorable effects of coating and pyroxene. The leaching rate of the roasting method of antimony-containing gold ore is high and the process is mature, but its accompanying minerals such as arsenic and sulfur will cause environmental pollution problems, and it needs to be reprocessed, with high energy consumption and power consumption.

2. Chemical alkali leaching method

The Alkali leaching method is mostly used for processing gold antimony ore with pyroxene as the main gold-containing mineral. This method makes use of the characteristics of pyroxene ore that can be well dissolved in alkali or sodium sulfide, removes the product in advance through water washing, avoids the occurrence of cyanide and oxygen depletion reaction in the subsequent cyanide leaching, and obviously weakens the secondary coverage of products such as sodium cyanide. Compared with the roasting method, the cyanide leaching rate of the chemical alkali leaching method will be lower, but it has the advantages of a fast reaction, short cycle, less pollution, and low cost.

Antimony Gold Ore Enhanced Leaching

The antimony gold ore enhanced leaching method is generally used in the cyanide leaching stage of antimony gold ore, through the addition of lead acetate, lead nitrate, and other leaching aids to avoid the cyanide and oxygen depletion reaction of antimony pyroxene in the process of cyanide leaching, and at the same time to avoid the reaction products of the gold particles caused by the secondary coverage; add potassium permanganate and other oxidizing agents to accelerate the oxidation of antimony pyroxene to generate antimonates, destroying the peripheral layer of the gold parcels, and at the same time to improve the reaction of the gold cyanide leaching reaction activity, accelerate the leaching speed. The enhanced leaching method does not require pretreatment of the raw ore, and at the same time can accelerate the leaching speed and improve the leaching efficiency, but it does not apply to the antimony gold ore with serious veinstone parcels.

In conclusion, the difficulty of separating antimony-bearing gold ore lies in the antimony minerals wrapping gold and pyroxene consuming cyanide and oxygen in the leaching process. Caused by antimony gold ore difficult to select different reasons, for different antimony gold ore nature, also need to choose different selection methods selection. For this kind of difficult-to-select gold ore, you need to carry out a beneficiation test first, after a comprehensive understanding of the nature of the ore, and then according to the beneficiation test report to choose scientific and reasonable antimony gold ore dressing methods and equipment.