SPRAY 007 - Spray Drying in Lithium Battery Material Production

Precursor Granulation and Process Evaluation

Process illustration: spray drying forms precursor granules; calcination is a subsequent process step.

Where Spray Drying Fits in Lithium Battery Material Production

Lithium iron phosphate (LiFePO₄, or LFP) is widely used as a cathode material in traction and energy storage batteries. Its performance depends not only on chemical composition, but also on particle structure, particle size distribution, carbon content, and subsequent heat treatment.

Spray drying atomizes a slurry containing solid components into droplets and rapidly evaporates water or solvent to form dry particles. In LFP production, it can be used for precursor drying and granulation. When the target is an LFP/C cathode material, the spray-dried precursor generally undergoes subsequent processing such as calcination.

Spray drying therefore addresses the conversion of slurry into dry particles. The final material’s crystal phase, carbon coating, and electrochemical performance are determined together by formulation, calcination, and post-processing.

What Spray Drying Can Offer in Precursor Granulation

1. Continuous particle formation with controllable powder morphology

Atomized droplets form particles as they dry. By selecting the atomization method and adjusting feed, atomization, and drying conditions, spherical or near-spherical secondary particles can be produced.

Spherical particles generally offer good flowability. Particle size, internal porosity, and packing affect tap density, so tap density must be measured as a product specification rather than inferred from appearance alone.

Spray drying suits processes that continuously convert slurry into dry particles. Compared with oven drying followed by milling, it eliminates the need to break up dried cakes and allows particle characteristics to be adjusted through atomization and feed conditions.

2. Co-drying the components present in the slurry

When the slurry is well mixed and dispersed, spray drying can dry its solid components together within the droplets, reducing settling associated with prolonged holding. Stable particle composition requires consistent upstream mixing, milling, dispersion, and feeding. Spray drying cannot correct upstream formulation or dispersion problems if the slurry agglomerates or settles.

3. Producing precursor powder for subsequent calcination

Spray-dried particles can serve as precursors for subsequent calcination. Their size, porosity, and compositional uniformity affect downstream heat treatment and powder properties. Process development should evaluate spray drying and calcination as connected steps.

Record particle size distribution, moisture content, tap density, and composition during trials. After calcination, test the crystal phase, carbon content, and electrochemical properties.

Three Equipment Requirements for Battery Material Spray Drying

1. Manage wear and contamination caused by wear

Slurries containing hard particles can wear atomizers, pumps, valves, and piping. Solids content, the proportion of hard particles, particle size, and atomization method all affect the location and rate of wear.

Equipment selection should identify the slurry’s abrasiveness and match the design and materials of construction to the wear-prone components. Silicon carbide, alumina ceramic, or hard alloys can be used for specific wear-resistant components, but no single material is a universal choice for every slurry.

Include wear parts in inspection and replacement schedules. Evaluate product-contact materials and surface treatments together to prevent contamination from wear, coating damage, or maintenance.

2. Control magnetic impurities across the process line

Battery material production requires control of metal contamination from raw materials, equipment wear, and maintenance. Magnetic separators remove ferromagnetic particles; they do not remove every metal contaminant. Copper and zinc, for example, cannot be removed by ordinary magnetic separation.

Select separator locations according to the process. Remove iron from incoming raw materials where appropriate, and consider magnetic separation or metal detection during dry powder conveying. A separator in a slurry line requires a design suited to the slurry state, filtration requirements, and separator geometry.

Gauss rating alone does not establish separation performance. Evaluate separator design, material flow rate, bed depth, particle condition, and target contaminants, then verify product quality using an agreed test method.

Product-contact parts may use stainless steel or other materials selected for the material and cleaning requirements. 316L stainless steel is not an iron-free material. Battery-grade contamination control therefore requires attention to equipment design, manufacturing, maintenance, and testing—not just the material grade.

3. Use a risk-assessed closed-loop system for organic solvents

If the process uses NMP, ethanol, or another organic solvent, design the closed-loop drying system for the specific solvent, evaporation load, and operating conditions. A closed-loop system uses nitrogen or another inert gas as the circulating medium and recovers solvent through a condenser.

The system requires oxygen monitoring and interlocks, pressure relief or other suitable protection, grounding, static control, and exhaust management. Set oxygen limits through the safety design for the solvent and system; one fixed value does not apply to every project.

Closed-loop circulation can recover part of the evaporated solvent and reduce oxygen ingress, but it does not eliminate all fire, explosion, or occupational exposure risks. System design, protective devices, and operating procedures must be assessed together.

LPG-5 for Small-Scale Trials and Preliminary Process Evaluation

Our LPG-5 spray dryer supports interchangeable rotary atomizer and spray nozzle configurations. It can be used in small-scale trials to compare powder formation under different atomization methods.

For battery material slurries, trials can focus on:

· Stable slurry feeding and atomization.

· Particle size distribution, morphology, and moisture content of the dried powder.

· Powder recovery and deposition on equipment surfaces.

· Effects of feed solids content, atomization conditions, and drying temperature.

LPG-5 results support preliminary process screening. Industrial production requires separate engineering for actual capacity, drying load, product-contact materials, magnetic impurity control, exhaust treatment, and safety systems. Small-scale trials do not replace industrial system validation.

Process Data to Define Before Testing

· Slurry composition, solids content, viscosity, and particle size.

· Dispersion medium and whether organic solvents are present.

· Target powder particle size, moisture content, and tap density.

· Subsequent calcination conditions and final product test criteria.

· Planned throughput and production schedule.

· Specific requirements for metal impurities, product-contact materials, and safety protection.

Evaluate the Spray Drying Route Through Material Trials

Spray drying can be used for precursor drying and granulation of lithium battery material slurries. Small-scale trials establish whether a slurry can be atomized and provide initial data on particle morphology, particle size, and powder recovery. The full process route is then evaluated alongside calcination and final product testing.

If you are developing LFP, NCM, or other battery powders, please share your slurry data, target throughput, and product specifications. Contact: info@machtechdryer.com , we can discuss trial configuration and preliminary testing.