Normally, gold is very difficult to be oxidized directly. In nature, gold oxide has been found, which occurs in areas close to the surface, and has experienced a long weathering process. So what is the oxidized gold mine, and what is the gold ore processing equipment? Let's understand it together!
Use the table of contents below to navigate through the guide:
Gold oxide is black or black-brown powder. It is sensitive to light, see light gradually decompose. It is insoluble in water, soluble in hydrochloric acid, concentrated nitric acid, sodium cyanide in aqueous solution. Gold oxide begins to decompose and lose oxygen at 110℃, becomes gold oxide at 160℃, and completely decomposes into metal gold at 250℃.
Gold oxide ore is easy to soak ore and can be directly leached out into the heap. However, some gold oxide mines still need to undergo fine grinding-sizing-precyanide-cyanide and carbon leaching-filtration-analytical treatment to obtain qualified gold minerals. The required equipment required is as follows:
Fine grinding is to grind the gold-containing oxide minerals, so that the ore size is smaller, forcing the fine gold fully dissociation, facilitate the subsequent cyanide reaction. The equipment used for fine grinding is mainly grid type ball mill, overflow ball mill and hydrocyclone. In the second section, the overflow ball mill is used to grind it to-325% to completely dissociate it, so as to shorten the subsequent contact time between gold particles and cyanide.
Oxdized gold ore slurry adjustment is to add water and lime to the fine grinding powder to obtain gold mine slurry. Then lime is used to adjust the pH value of the slurry to inhibit hydrogen hydrolysis in the process of cyanide treatment, neutralize the sulfuric acid and carbonated acid produced in the process of cyanide, and avoid the action of H and cyanide to produce HCN (hydrogen cyanide). In addition, it can also reduce the destruction effect of iron minerals on CN- (cyanide ion).
When slurry adjusting, it should be noted that the amount of limestone should be based on the amount of gold mine powder. Generally, the liquid-solid weight ratio of the pulp is 2-4:1, which is convenient for the pressurization process, and can ensure that the activated carbon is suspended in the pulp, so as to facilitate the subsequent adsorption operation. The equipment required in this stage is mainly high efficiency agitation tank and conventional agitation tank.
The precyanidation treatment of oxidized gold mine is to put the stirred ore slurry into the pressure kettle and add sodium cyanide (reaction under the pressure of 0.6MPa~1.0MPa). The general cyanide pretreatment time is 0.5-2 hours to ensure that the precyanide reaction is fully conducted. Its stirring speed is in the range of 600-1200 r/min, which can promote the diffusion of CN-and oxygen in the pulp and improve the pretreatment efficiency.The equipment required in this stage is pressure kettle and pharmaceutical agitation tank.
Cyanization process is after pre-cyanide, activated carbon is fed into the pressurized kettle (the amount of activated carbon added is generally 20~40g / L) for cyanide and carbon immersion treatment. The main purpose is to facilitate the adsorption of complex alloy ions produced by activated carbon.
When the cyanide reaction is carried out in a closed pressurized kettle (3-8 hours), the dissolved oxygen in the pulp increases, which effectively accelerates the reaction. When the activated carbon is added to the pulp, the activated carbon can adsorb the complex alloy ions extracted from the pulp in time, reduce the concentration of the complex alloy ions in the pulp, and accelerate the gold immersion reaction. The equipment required for this stage is the leaching tank and the carbon lift device.
The liquid obtained after cyanide leaching needs further filtration treatment to facilitate the separation of the activated carbon adsorbed with complex alloy ions and the pulp after the gold extraction. The active carbon of complex alloy ions can be separated from the slurry by 30 target sieve. However, there are also gold ions in the slurry, which can be further processed by the thickener to obtain the supernatant and return it to the cyanide pretreatment stage, which can effectively reuse the supernatant. The equipment required for this stage has a filter screen and a three-layer washing thickener.
The desorption of gold oxide is the desorption of the active carbon obtained after filtration to obtain qualified gold concentrate. The desorption electrolysis is mainly completed in the desorption column. The washing quickly loaded gold activated carbon is loaded into the desorption column, and then the aqueous solution of sodium cyanide and sodium hydroxide is added to soak the carbon layer. When the temperature reaches 90℃ ~95℃, gold can be obtained within a certain time range. The equipment required at this stage is mainly a complete set of analytical electrolytic system, including desorption column, electrodeposition tank, electric heater, carbon storage tank, filter, desorption tank, etc.
The characteristics of gold oxide and the types of gold oxide beneficiation equipment are introduced above. The equipment selection is mainly based on the gold oxide beneficiation process plan. Therefore, Xinhai suggests that gold ore should be selected for beneficiation test analysis to design a suitable oxidation gold beneficiation process and improve gold recovery efficiency.