With the development of new energy industry, the demand for lithium salt is increasing. Spodumene is the main lithium source, and lithium extraction process from spodumene is the key technology in lithium salt production industry. The chemical property of natural spodumene is stable, and the chemical index control of direct lithium extraction is more stable than that of brine lithium extraction. At present, the main process of extracting lithium from spodumene is to convert naturally stable a-spodumene into chemically active through high temperature β Spodumene, and then extract lithium through grinding, acidification and other processes. So, which spodumene grinding mill is selected for spodumene powder process? HCMilling(Guilin Hongcheng), as a manufacturer of spodumene grinding mill, compares the advantages and disadvantages of ball mill and spodumene vertical roller mill in the spodumene grinding process.

Which spodumene grinding mill is selected for spodumene powder process? Spodumene calcined material is difficult to grind, and its characteristics are as follows: ① poor grindability, and the grindability changes greatly; ② High abrasiveness of raw materials; ③ The particle size of raw materials is small, and there are many powdery materials; ④ There is very little water in the material; ⑤ The fineness of the product is coarse, but the abrasiveness is large. In view of these characteristics of materials, the mill needs to design a reasonable speed of the grinding disc, and a large number of wear-resistant materials need to be used in terms of wear resistance; Material characteristics shall also be set in the process system design. A domestic company has two lithium salt production lines, and the open circuit system of 3.8 mX13 m ball mill is used for the vertical roller mill of baking material in one production line. In 2021, its subsidiary will launch a new lithium salt project with an annual output of 30000 tons. Through many investigations, it will finally use more energy-saving spodumene vertical roller mill equipment to replace the traditional ball mill process. Since the project was put into operation in January 2022, all indicators are good. Compared with the open circuit system of ball mill, the spodumene vertical roller mill system is simple, energy-saving, and the product fineness is easier to control.

Ball mill process flow of spodumene grinding lithium concentrate powder process:

Calcined spodumene（βSpodumene) is sent to the raw material warehouse by the conveying equipment after being cooled and crushed by the grate cooler, and the calcined materials are sent to the ball mill through the lower rod valve of the warehouse, the metering scale, the sealing belt, the elevator and other equipment, and then directly enter the warehouse after being grinded by the ball mill (the ball mill is an open circuit system). The ball mill system is ventilated by a separate fan to assist the material flow in the ball mill.

Technological process of spodumene vertical roller mill for preparing lithium concentrate powder:

Calcined spodumene（βSpodumene) is sent to the raw material warehouse by the conveying equipment after being cooled and crushed by the grate cooler, and the calcined material is sent to the vertical roller mill through the lower rod valve, metering scale, sealing belt, elevator and other equipment in the warehouse. The motor driven reducer of the vertical roller mill drives the grinding plate to rotate. The materials to be grinded are sent to the center of the rotating grinding plate by the air lock feeding equipment. Under the centrifugal force, the materials move around the grinding plate and enter the grinding roller table. Under the action of grinding roller pressure, materials are crushed by extrusion, grinding and shearing. At the same time, air is ejected from the wind ring around the grinding plate at a high speed and evenly, and the material after grinding is blown up by the high-speed airflow at the wind ring. On the one hand, the coarse material is blown back to the grinding plate for grinding again; On the other hand, fine powder is brought into the separator by air flow for grading. Qualified fine powder flows out of the mill with air and is collected by the dust collection equipment as a product. Unqualified coarse powder falls back to the mill plate under the action of separator blades and is grinded together with newly fed materials. In this way, the whole process of grinding operation is completed. Materials that are particularly difficult to grind are discharged from the slag discharge port, which can be returned to the spodumene vertical roller mill for grinding through the elevator, You can also throw it away directly.

Comparison between ball milling and spodumene vertical roller milling of spodumene powder:

Through comparison, it is found that compared with the spodumene vertical grinding mill system, the ball mill system has higher installed power, lower output, coarser product fineness and is difficult to control, and the feed particle size is required to be smaller than the vertical roller mill system. At the same time, the use of the ball milling system requires frequent water spraying for cooling, and the production environment is poor. Therefore, it is necessary for the industry to replace the traditional ball mill with a more energy-saving and environment-friendly vertical roller mill. The investment of spodumene vertical roller mill system is slightly higher, but its use area, power consumption, wearing parts, maintenance, noise, factory environment, etc. are better than ball mill. The successful operation of this technology shows the advantages of high grinding efficiency, simple system, simple operation and convenient maintenance. Compared with the ball mill system, this system has lower production cost (power consumption and operation cost), less wear of vulnerable parts per unit product, system negative pressure production, clean environment and low noise.

Meanwhile, the production line can be arranged in the open air, and the civil construction investment is small. The technology has good economic and social benefits when applied to lithium salt industry. If you have any needs, please contact mkt@hcmilling.com or call at +86-773-3568321, HCM will tailor for you the most suitable grinding mill program based on your needs, more details please check www.hcmilling.com.