After beneficiation and purification of graphite ore, graphite concentrate is obtained, which can be used for the production of negative electrode materials for lithium batteries. In addition, graphite plays a crucial role in lubrication, wear resistance, corrosion, energy storage, and other fields. However, how to treat graphite tailings is also a difficult problem that comes with it. How can we achieve the comprehensive utilization of graphite tailings when traditional tailings ponds are explicitly prohibited? In fact, the key lies in scientific processing methods.
The traditional tailings pond involves storing and treating tailings. This extensive treatment method not only causes pollution to the environment and atmosphere, but also poses safety hazards to the property safety of people living nearby. At the same time, it is also a waste of resources. In today's gradually depleted resources, valuable minerals in tailings may create great value.
What valuable minerals exist in graphite tailings?
In nature, there are fewer solitary minerals and more associated minerals. In addition to graphite, graphite ore also contains metal minerals such as pyrite, pyrrhotite, and porphyry, as well as rare metal minerals such as rutile. Some of these minerals have high content and have recycling value.
How to conduct comprehensive recycling?
The types and quantities of valuable minerals contained in different graphite tailings are different, and the recovery methods are also different. It needs to be determined through beneficiation experiments. Taking a certain graphite tailings as an example, let's learn the method of comprehensive recycling together.
The particle size of tailings in a certain graphite mine tailings pond is relatively fine, with -0.074 mm accounting for 89.48%. Useful minerals include: graphite content is 4.87%, there are many types of gangue minerals, mainly quartz and sericite, with a content of about 20%.
The graphite content of the tailings varies greatly among different particle sizes, and the graphite in the sample is amorphous graphite, mostly in the form of flake or parallel graphite aggregates and granular monomers. It has strong heterogeneity, with biotite and sericite distributed in flakes and strips, some of which are connected with graphite, quartz mostly distributed in heteromorphic granular form, and some are connected with graphite.
The treatment method for graphite tailings: 1 coarse, 1 fine, 4 stages grinding, 5 stages selection, 1 high grade intermediate ore direct return, and 1 low grade intermediate ore concentrated cleaning, followed by a return process to process the sample. Finally, a graphite concentrate with a fixed carbon content of 85.65% and a recovery rate of 66.22% was obtained, which meets the quality standards of refractory grade graphite materials specified in GB3519-83.
When there are indeed no valuable elements worth recycling in graphite ore, another graphite tailings treatment method can be considered: tailings dry discharge.
Tailings dry discharge refers to the process of multi-stage concentration of graphite tailings slurry, followed by efficient dehydration equipment such as a vibrating screen, to form slag with low water content, easy to settle and solidify, and stored on site. The slag can be transported to a fixed location for dry storage.
The process flow of tailings dry discharge: Graphite tailings are transported to a hydrocyclone through a slurry pump. For coarse-grained tailings with good filtration performance, they can directly enter a high-frequency dewatering screen, and after dehydration, they are transported to a fine-grained tailings pond through a belt conveyor.
For fine-grained tailings, they need to enter the high-efficiency thickener through a hydrocyclone, and the bottom flow is dehydrated through a box filter press. Finally, they are sent to the fine-grained tailings pond through a belt conveyor.
Advantages of Xinhai tailings dry discharge:
1. Experts with rich experience in leading the team: When it comes to tailings dry discharge, one cannot help but mention the founder Yu Yongjiang. In 2009, Yu Yongjiang led the Xinhai technical team to design and develop an earlier tailings dry discharge test bench in China, which contributed to promoting the development of China's tailings dry discharge process. Xinhai has undertaken hundreds of tailings dry discharge projects so far, which can be said to be experienced;
2. Good dewatering effect: Xinhai's tailings dry discharge process is completed three times in sequence by a hydrocyclone, deep cone thickener, and high-frequency dewatering screen, with a final concentration of over 85%;
3. Low operating cost: The unique equipment combination of tailings dry discharge process reduces equipment investment and civil engineering investment;
4. Long service life of equipment: The equipment used in the tailings dry discharge process is lined with Xinhai wear-resistant rubber, with a wear resistance index of up to 128%, greatly extending the service life of the equipment.
Application fields of comprehensive utilization of graphite tailings
The tailings after dry discharge and dehydration have been effectively utilized in many fields, mainly including:
1. Preparation of white carbon black
The process of using graphite tailings to produce white carbon black involves crushing the tailings and then adding alkali roasting, followed by water leaching, acid reaction, washing, drying, and crushing to produce white carbon black. This method is also a favorable way for the comprehensive utilization of graphite tailings.
2. Applied in the field of building materials
The application of graphite tailings in the field of building materials can be used to produce wall materials, load-bearing sintered bricks, sintered porous bricks, environmentally friendly ceramic ecological bricks, etc.
3. Used as the base layer of highway pavement
Although China has continuously made new achievements in the research of graphite tailings treatment methods in recent years, the utilization technology level of graphite tailings is still low and the utilization rate is not high. Graphite tailings have uniform particles, mainly composed of silicon oxide, high hardness, good wear resistance, and strong permeability, making them ideal raw materials for preparing permeable materials. In the future, the development prospects of graphite tailings are very clear, and they have broad application prospects in fields such as chemical engineering, environmental protection, hydropower, and road construction.
