The Tanzania 1,200t/d gold mineral processing plant, as a large-scale EPC+M+O project undertaken by Xinhai, has a complete and scientific production process, which is divided into four core stages: crushing, grinding and classification, separation (all-slime cyanidation), and tailings treatment. Each stage is closely connected and mutually supportive, forming a complete production system. The rational design and strict control of each production stage are the key to ensuring the plant’s 1,200t/d production capacity, high leaching rate and stable operation. This article will interpret each production stage in detail, showing Xinhai’s professional design and refined management in the project.
The crushing stage is the first link of the entire mineral processing process, responsible for breaking large raw ore into small particles that meet the requirements of the grinding stage. The Tanzania project adopts an open-circuit crushing process, which is a scientific choice based on the characteristics of the raw ore and the project’s production scale. The raw ore mined from the mine has a large particle size, generally up to several meters, which cannot be directly entered into the mill for grinding. The open-circuit crushing process is composed of multiple crushers, which break the raw ore step by step from coarse to fine.
In the crushing stage, Xinhai selected advanced and efficient crushing equipment according to the hardness and particle size of the raw ore, ensuring the crushing efficiency and product quality. The first stage of crushing uses a jaw crusher to break large raw ore into coarse ore with a particle size of less than 300mm; the second stage uses a cone crusher to further crush the coarse ore into medium ore with a particle size of less than 50mm; the third stage uses a impact crusher to crush the medium ore into fine ore with a particle size of less than 10mm, which meets the feeding requirements of the grinding stage. The open-circuit crushing process has the advantages of simple flow, high crushing efficiency and low energy consumption, which is very suitable for large-scale production. At the same time, Xinhai equipped the crushing workshop with professional dust removal equipment to reduce dust pollution and meet the local environmental protection requirements.
The grinding and classification stage is the core link to realize the dissociation of gold particles, which directly affects the subsequent leaching effect. The Tanzania project adopts a one-stage closed-circuit grinding and cyclone classification process, which is an advanced grinding and classification mode in the current mineral processing industry. The closed-circuit grinding means that the ore after grinding is sent to the cyclone for classification, and the unqualified coarse-grained ore is returned to the mill for regrinding, while the qualified fine-grained ore enters the subsequent cyanidation leaching stage. This cycle ensures that the grinding product has a uniform particle size and sufficient dissociation of gold particles.
Xinhai selected a large-scale energy-saving ball mill for the grinding stage, which has the advantages of high grinding efficiency, low energy consumption and stable operation, and can meet the grinding demand of 1,200t/d ore. The cyclone used in the classification stage has the characteristics of high classification efficiency and accurate classification, which can effectively separate coarse and fine ore particles. The technical team of Xinhai optimized the matching parameters of the mill and cyclone through experiments, determined the optimal grinding concentration and classification efficiency, and ensured that the particle size of the grinding product reaches -200 mesh accounting for more than 85%, laying a solid foundation for the subsequent all-slime cyanidation leaching.
The separation stage adopts the all-slime cyanidation process, which is the core link of gold extraction. The qualified ore pulp after grinding and classification is sent to the cyanidation leaching tank, and cyanide solution and lime are added to carry out the leaching reaction. The lime is used to adjust the pH value of the pulp to prevent the cyanide from being decomposed and improve the leaching effect. During the leaching process, the aeration device continuously aerates the pulp to promote the reaction between gold particles and cyanide solution, so that the gold is dissolved into the solution to form gold cyanide complex.
After the cyanidation leaching, the gold-bearing solution is adsorbed by activated carbon to obtain gold-bearing carbon, which then enters the desorption electrolysis system. The desorption electrolysis system uses high temperature and high pressure to desorb the gold from the activated carbon, and then obtains gold mud through electrolysis. The gold mud is smelted to obtain finished gold. The tailings after cyanidation leaching are sent to the thickening and dewatering system for solid-liquid separation. The separated clear water is recycled to the production system for reuse, and the dewatered tailings are stacked in the tailings yard, realizing the harmless treatment and resource utilization of tailings.
Each production stage of the Tanzania 1,200t/d gold plant is designed and managed in a refined way, which ensures the efficient and stable operation of the plant. The close connection between the stages and the optimized process parameters make the plant’s production capacity and leaching rate reach the design requirements, providing a reliable guarantee for the project’s economic benefits. Xinhai’s professional technical strength and refined management level are fully reflected in each production stage, setting a good example for the construction of similar gold processing plants in East Africa.
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