What are the equipment for zinc powder replacement gold extraction?

Zinc powder replacement gold extraction is a common method for gold extraction. It mainly uses zinc powder in a solution containing cyanide gold complex to replace gold ions with its reducing property, thereby realizing gold extraction. Zinc powder replacement gold extraction has high efficiency and relatively low requirements for equipment. It can effectively obtain high-purity gold from cyanide leaching solution. In the process of zinc powder replacement gold extraction, the use of equipment is very important and is also the key to its gold extraction efficiency. This article will introduce to you what are the main equipment used in zinc powder replacement operations?

011. Replacement mixing tank

The function of the mining tank is to turn on the stirring function during the zinc powder addition stage, so that the added zinc powder is quickly and evenly dispersed in the gold-containing solution to avoid zinc powder agglomeration, thereby increasing the contact area between the zinc powder and the gold-containing solution. Entering the replacement reaction stage, continuous and stable stirring can maintain the solution in a dynamic mixing state, ensure that the zinc powder and gold ions fully collide, and accelerate the replacement reaction rate.

Xinhai stirring tank is generally composed of tank body, stirring device, transmission device, etc. The tank body is mostly made of corrosion-resistant materials to cope with chemical erosion of different agents.

022. Zinc powder adding equipment

Zinc powder adding equipment can accurately and quantitatively add zinc powder to the solution system containing gold cyanide complex. Its function is to ensure that zinc powder is evenly dispersed in the solution, so as to promote the full reaction of zinc powder and gold ions, achieve efficient replacement and gold extraction, and improve the extraction rate and purity of gold. The equipment mainly includes screw feeder, metering pump, etc.

Screw feeder: It rotates at a constant speed under the drive of the motor to transport zinc powder from the silo to the reaction system. By adjusting the motor speed, the amount of zinc powder added can be accurately controlled. In actual production, some gold mines use automatic control systems to adjust the speed of the screw feeder in real time according to the online monitoring of gold solution concentration, flow rate and other parameters, to ensure that the amount of zinc powder added always matches the amount of gold to be replaced in the solution, avoiding waste or insufficient addition of zinc powder.

Metering pump: It is a type of positive displacement pump that can control the flow rate of liquid or powder. In the process of zinc powder replacement of gold, special zinc powder conveying accessories are often used to evenly and stably inject zinc powder into the gold-containing solution. The flow adjustment range of the metering pump is wide, which can be adjusted within the range of 0-100%, and the accuracy can reach ±1%. When processing high-grade gold-containing solutions, the use of metering pumps can ensure that zinc powder is added in proportion, give full play to the role of zinc powder, and improve the gold replacement effect.

033. Solid-liquid separation equipment

After zinc powder replacement, gold precipitates from the solution in solid form and forms a solid phase with unreacted zinc powder. There are also substances such as cyanide in the solution to form a liquid phase. If solid-liquid separation is not performed, the final product will be a mixture of gold, zinc powder and solution, and pure gold products cannot be obtained. Therefore, solid-liquid separation is required. Commonly used equipment includes filters, concentrators and centrifuges.

Concentrator: mostly used for preliminary separation. Through the principle of gravity sedimentation, the gold mud is gradually concentrated at the bottom of the equipment, and the supernatant overflows and is discharged from the top.

Filter: After the zinc powder replacement is completed, the filter plate is compressed by its own hydraulic system, forcing the solution containing gold mud to pass through the filter cloth under pressure. The solution flows out through the filter cloth, and the gold mud is trapped on the surface of the filter cloth to form a filter cake. Its filtration pressure can reach 0.6-1.0MPa, which can effectively treat high-concentration suspensions and has a high recovery rate for gold mud.

Centrifuge: With the help of the centrifugal force generated by high-speed rotation, the solid-liquid separation process is accelerated. In the high-speed rotating drum, the gold mud is thrown to the drum wall under the action of centrifugal force and discharged through the screw conveyor, while the solution flows out from the other end of the drum. It is mostly suitable for some gold mud with fine particle size and difficult to settle.

044. Gold mud processing equipment

The gold mud after zinc powder replacement is often mixed with unreacted zinc powder, other impurities and residual cyanide, etc. Therefore, it can be removed by gold mud treatment to improve the purity of gold so that it can be refined and processed into gold products that meet market standards. Commonly used equipment is mainly cleaning equipment, drying equipment and smelting equipment. Cleaning equipment: The stirring tank can also be used as a device for cleaning gold mud. Add clean water or dilute acid solution to the gold mud, start stirring, and wash away impurities such as cyanide and zinc ions remaining on the surface of the gold mud. There are also special gold mud cleaning machines that can efficiently clean gold mud through spraying, vibration and other methods, reduce residual impurities, and improve the purity of gold mud.

Drying equipment: The oven heats the air to evaporate the water in the gold mud and achieve drying. The dryer uses hot air circulation, vacuum drying and other methods to quickly remove the moisture in the gold mud. Some vacuum dryers can achieve drying at a lower temperature to avoid chemical reactions of impurities in the gold mud due to high temperature, which affects the purity of gold.

Melting equipment: The electric furnace uses electric current to generate heat through resistance to melt the gold mud. The temperature can be as high as 1500℃ or above, which can effectively melt the gold mud and separate gold from other impurities. The reverberatory furnace heats the gold mud through the high-temperature flame and heat radiation generated by the combustion of fuel. Its furnace space is large and suitable for large-scale smelting operations. During the smelting process, flux is added to further reduce the melting point of gold, improve smelting efficiency, and finally obtain high-purity gold ingots.

The above are the commonly used equipment in zinc powder replacement gold extraction operations. These equipments work closely together, from zinc powder addition, replacement reaction, to solid-liquid separation, gold mud treatment, forming a complete system. With the advancement of technology, the equipment is constantly innovating in automation, efficiency, and environmental protection, promoting the continuous optimization of the zinc powder replacement process of gold and improving the efficiency and quality of gold extraction.