Dry Grinding

Rounding Unit GyRho

Efficient and Economical Spheroidization

Process Technology for the Rounding of Graphite

Ideally, spherical graphite is required for the production of the anodes of lithium-ion batteries. 

Natural graphite and synthetically produced graphite are platelet-shaped and show a characteristic layer structure. The goal of further process steps, including comminution, is therefore to achieve a rounded product with a narrow particle size distribution as well as high tap density and yield.

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NETZSCH GyRho Rounding Unit 

The NETZSCH Process – GyRho Rounding Unit

The graphite rounding process developed by NETZSCH overcomes disadvantages of the previously widespread used process requiring more than 20 classifier mills installed in rows: In a first step, the flock graphite is pre-ground to the optimum initial particle size for spheroidization in a classifier mill or fluidized bed jet mill. 

The actual particle rounding process takes place directly downstream in the newly designed NETZSCH GyRho Rounding Unit (Fig. 2) which is available in various construction sizes and can be specially designed to suit the necessary output quantity. For larger throughput volumes two (or more) machines can be operated simultaneously and can replace the train of 20 machines or more as mentioned above.

The efficient spheroidization process in the GyRho is divided into three phases: Filling, Rounding and Discharging. During the filling phase, the maximum product volume is conveyed into the process chamber. In the rounding phase, the particles are stressed to the point of rounding by optimum geometry and process parameters, and in the final step, the emptying phase, the process chamber is emptied by suction with a cyclone and the product is separated.

NETZSCH Rounding Unit GyRho size
NETZSCH GyRho Rounding Unit
Graphite Spheroidization Plant with a Pre-Grinding Unit CSM and a Rounding Unit GyRho
Example of product: Yield = 49.3 wt.-%, d50 = 18.4 µm, tap density = 1019 g/l

By optimizing the design of the grinding chamber and reducing the number of components, it was possible to increase yields of 30 to 40% achieved by the standard system to 60 to 65% with the GyRho. At the same time, using specific settings, it is possible to achieve the maximum yield of final product with the desired quality. Quality criteria such as distribution width, tap density and particle size can be influenced by varying the process parameters. In this way, using the GyRho system, all qualities required by the market, such as spherical graphite with a tap density of more than 960 g/l at a d50 value of 16.8 µm and a yield based on a raw material volume of > 60% are achievable.


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Your Benefits

Plant data for the NETZSCH GyRho System compared to competitors´ systems

30 % higher plant availability
in comparison to previously used processes 
65 % total yield*
thanks to the innovative plant concept, optimized grinding chamber- and classifier design
 * up to 65 % total yield based on amount of raw material and depending on its origin and type
35 % lower operating costs*
compared to standard plant trains
 * Opportunity-, working-, spare part-, electricity costs, depreciation and costs for graphite concentrate
90 % lower maintenance costs
thanks to a significantly lower number of machines
60 % smaller surfaces
at identical production capacity thanks to compact setup
60 % less energy
for identical production capacity (half of installed power and optimized operation mode)



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NETZSCH GyRho – Spheroidization Plant 

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