Spheroidization is a core value-adding process in lithium-ion battery graphite anode manufacturing, which transforms irregular flake graphite into near-spherical particles with ≥0.85 sphericity to boost tap density and electrochemical performance. However, the mechanical rounding action inherently removes sharp edges and corners from raw particles, generating substantial ultra-fine powder that is separated from the final product, resulting in inevitable yield loss. This loss directly determines raw material utilization rate and production cost, and its magnitude varies widely across different process routes and equipment configurations. As a leading provider of graphite processing technology with 19 years of engineering experience, JACAN Powder Equipment has optimized its spheroidization modification and classification processes to effectively control yield loss while delivering high sphericity and consistent product quality.
Core sources of spheroidization yield loss
Yield loss in graphite spheroidization primarily comes from the mechanical material removal mechanism itself. To achieve smooth, near-spherical morphology, graphite particles are subjected to repeated impact, friction and shearing forces inside the spheroidization chamber. The sharp edges and protruding corners of flake graphite are gradually worn away, forming a large amount of sub-10μm ultra-fine powder. These fine particles are separated from the product fraction by the air classification system and collected as by-products or waste, constituting the main part of yield loss.
Additional loss sources include over-ground particles degraded by excessive mechanical action, product entrainment in the dust collection system, and a small amount of material residue in the equipment. Among them, controllable process factors such as mismatched classification parameters and excessive spheroidization intensity account for a large proportion of avoidable loss. For industrial production, total yield loss is usually calculated as the mass percentage of non-qualified fine powder and waste relative to the total feed mass entering the spheroidization process.
Typical yield loss levels by process technology
There is no universal loss value for graphite spheroidization, as it differs drastically with equipment type and process design. Industry data shows that yield loss can range from 20% to over 70% depending on the technical route adopted.
Traditional cascade spheroidization: 50–70% yield loss
Early conventional cascade spheroidization lines rely on multiple serial grinding-shaping cycles to gradually round graphite flakes. Due to the lack of precise classification control, particles stay in the processing system for a long time and suffer repeated excessive impact, generating a large amount of ultra-fine powder. This process typically achieves only 30–50% product yield, corresponding to 50–70% yield loss. Most of the lost material is fine powder below 10μm that cannot be used as mainstream anode product, resulting in very low raw material utilization efficiency. This technical route has been gradually phased out in large-scale production of high-end anode materials.
Single-machine classifier mill spheroidization: 30–50% yield loss
The widely adopted classifier mill spheroidization system integrates shaping and classification in one unit, discharging qualified particles in time through a built-in classifier wheel to reduce over-grinding. Under conventional process configurations, this solution achieves a product yield of 50–70%, with yield loss controlled at 30–50%. For standard D50 15–25μm anode graphite with sphericity around 0.8, this is the most common yield level in the current industry. However, when higher sphericity (≥0.85) is required, longer processing time will lead to increased fine powder generation, and yield loss may rise by 10–15 percentage points.
High-precision rotor impact shaping: 20–45% yield loss
High-end rotor impact spheroidization equipment adopts specially designed shaping chambers and controlled mechanical force modes, which mainly perform surface rounding rather than bulk crushing. This technology can achieve higher sphericity with less fine powder generation. According to industry research, well-optimized rotor impact systems can achieve 55–80% product yield under mainstream anode specifications, with yield loss reduced to 20–45%. When paired with precise classification control, this solution achieves the best balance between sphericity quality and yield efficiency.
Optimized closed-loop process with fines recovery: <20% comprehensive loss
When the production line is equipped with multi-stage classification and fine powder graded recovery systems, the ultra-fine powder generated by spheroidization can be classified into different particle size fractions and used as special graphite products for other applications. In this case, although the yield loss of the main product fraction remains at the above level, the comprehensive material utilization rate can be increased to more than 80%, and the total process loss is reduced to less than 20%. This has become the development direction of modern large-scale graphite anode production lines.
Key factors affecting spheroidization yield loss
For a given equipment system, yield loss is not fixed, but is jointly determined by product requirements and process parameter settings.
Target sphericity level
Higher sphericity requirements mean more edge material needs to be removed from particles, which directly increases fine powder generation. Published research on graphite rounding technology shows that when shaping time is extended from 30 minutes to 80 minutes to pursue higher sphericity and tap density, product yield drops sharply from 53% to 41%, and yield loss rises from 47% to 59% correspondingly. For JACAN’s standard ≥0.85 sphericity specification, the process parameters are precisely calibrated to achieve the target morphology without excessive material removal, avoiding unnecessary yield loss.
Raw material properties
The morphology and particle size distribution of feedstock have a significant impact on loss. Raw flake graphite with high aspect ratio and sharp edges requires more rounding processing and produces higher loss. In contrast, graphite that has undergone pre-grinding and preliminary shaping in the previous process has smoother edges, so the loss in the subsequent spheroidization stage is significantly reduced. This is also the reason why JACAN sets up an independent grinding and shaping process before spheroidization modification: the front-end pre-optimization of particle morphology reduces the processing load and material loss in the spheroidization stage.
Classification matching accuracy
The matching degree between the classification system and the spheroidization process determines how many qualified particles are retained and how many fine particles are accurately separated. Poor classification accuracy will cause two kinds of losses: on the one hand, unqualified coarse particles are mixed into the finished product, reducing product quality; on the other hand, qualified medium particles are mistakenly carried into the fine powder fraction, increasing unnecessary yield loss. Precise air classification can ensure that particles reaching the target size and sphericity are discharged in time, avoiding over-processing and reducing fine powder generation.
JACAN’s approach to minimizing spheroidization yield loss
Based on its four-step core process for graphite anodes, JACAN has formed a systematic yield optimization solution that balances high sphericity and low loss.
First, the process adopts a clear division of labor between grinding and spheroidization. The grinding and shaping process completes 10–50μm precision grinding and preliminary edge optimization, converting raw flake graphite into near-spherical intermediate particles. The subsequent spheroidization modification process only performs fine surface rounding and modification to reach ≥0.85 sphericity. This step-by-step morphology upgrading avoids a large amount of crushing and material loss in the high-intensity spheroidization stage, fundamentally reducing fine powder generation.
Second, the spheroidization system is matched with a high-precision air classification closed-loop design. Qualified particles are separated and discharged in time once they reach the target sphericity and particle size, avoiding prolonged retention and repeated impact in the shaping chamber. This not only prevents over-grinding, but also minimizes unnecessary edge wear, effectively controlling the yield loss while ensuring product consistency.
Third, the classification and post-treatment stage realizes graded recovery of materials of different particle sizes. The ultra-fine powder separated from the spheroidization process is classified and collected by particle size grade, which can be used as raw materials for other low-end or special graphite applications, greatly improving the comprehensive utilization rate of raw materials and reducing the actual economic loss caused by yield decline.
Finally, JACAN’s intelligent process control system precisely adjusts parameters such as rotor speed, airflow rate and material residence time according to different raw material characteristics and product specifications. With hundreds of technical patents and verification from 1,200+ global clients, the system can find the optimal balance point between sphericity index and yield loss for each product specification, helping customers achieve the best economic benefits while meeting high-quality product standards.
The typical yield loss in graphite spheroidization covers a wide range, mainly determined by the adopted process technology and product performance requirements. Traditional cascade processes face 50–70% high loss, while mainstream classifier mill systems have 30–50% loss, and optimized high-end shaping processes with fine powder recovery can reduce comprehensive loss to below 20%. For the mainstream high-end anode graphite with ≥0.85 sphericity and 10–50μm particle size, the industry’s advanced process level can control the main product yield loss at 25–40%.
Through front-end pre-shaping, closed-loop classification control and graded material recovery, JACAN’s integrated graphite processing solution effectively reduces spheroidization yield loss while ensuring high sphericity and batch consistency, providing manufacturers with a technical path to improve material utilization and reduce production costs.
