A 1,000 kg Load Does Not Determine the Bag Dimensions

When purchasing a Lithium Carbonate FIBC Bag, buyers often provide a target filling weight of 1,000 kg and ask the supplier to recommend the dimensions.

However, 1,000 kg only defines the target mass. It does not indicate how much space the material will occupy. The required bag volume also depends on the actual bulk density of the lithium carbonate powder.

For the same 1,000 kg filling weight:

• Lower bulk density requires more volume.
• Higher bulk density requires less volume.
• An undersized bag may not hold the target weight.
• An oversized bag may leave excessive unfilled space and affect the filled profile.

Load capacity and required volume must therefore be evaluated separately.

What Is the Bulk Density of Lithium Carbonate?

Bulk density is the mass of powder within a given volume, including the spaces between particles. It is commonly expressed in:

• kg/m³
• g/cm³

The conversion is:

1 g/cm³ = 1,000 kg/m³

Lithium carbonate bulk density may be influenced by:

• Particle size
• Particle-size distribution
• Particle shape
• Processing and screening methods
• Moisture condition
• Transportation vibration
• Natural settling or compaction during filling

Bag selection should use the bulk density under the intended filling condition. Material true density or reference values from another grade or batch should not be used as a direct substitute.

How Is the Required Volume Calculated?

Use the following formula:

Required material volume (m³) = filling weight (kg) ÷ bulk density (kg/m³)

For a target load of 1,000 kg:

These values demonstrate the calculation only. They are not actual lithium carbonate bulk-density data from the supplied production sheet. Final selection must use customer-provided or tested values.

If bulk density changes from 600 to 1,000 kg/m³, the theoretical volume occupied by the same 1,000 kg load changes from approximately 1.67 to 1.00 m³.

How Should a 108 × 108 × 125 cm Bag Be Evaluated?

The existing bag has nominal dimensions of:

108 × 108 × 125 cm

Converted into metres, its external geometric volume is:

1.08 × 1.08 × 1.25 ≈ 1.46 m³

However, 1.46 m³ is only the geometric volume calculated from the nominal dimensions. It is not automatically the effective filling volume.

Usable space is also affected by:

• The filling spout and top-panel construction
• Headspace required for closing
• The bottom panel and discharge spout
• Four internal baffles
• Natural powder distribution
• Bag deformation after filling
• Maximum permitted filling height

The result of “1.46 m³ × bulk density” should therefore be treated as an initial estimate, followed by an actual sample filling test.

What Happens If the Bulk Density Is Incorrect?

Insufficient bag volume

If the actual bulk density is lower than the design value, 1,000 kg requires more space. Possible results include:

• Failure to reach the target filling weight
• Material reaching the top of the bag
• Difficulty closing the filling spout
• Unexpected pressure on the baffles and walls
• Filled height exceeding the equipment limit

Excessive bag volume

If the actual bulk density is higher than the design value, 1,000 kg occupies less space. Possible results include:

• Excessive headspace
• An incompletely filled profile
• Baffles not reaching their intended working position
• A filled shape different from the design
• Increased material movement during transportation

Incorrect filling-equipment settings

Inaccurate bulk-density data may also affect:

• Filling time
• Volumetric feeder settings
• Weighing-system parameters
• Fill-height detection
• Production cycle time

For a weight-controlled filling line, the weighing system should be the final control. Filling should not stop only according to time or estimated volume.

Why Must Baffles Also Be Matched to Bulk Density?

The bag contains four 56 × 100 cm internal baffles that restrain lateral wall expansion.

Their profile-control effect depends on the filling condition:

• With insufficient volume, the baffles may not fully extend.
• With excessive volume, the baffles and seams may experience greater pressure.
• Uneven material distribution can create different pressures on each wall.
• Poor-flowing powder may not move evenly through the baffle openings.

Baffle dimensions and openings should therefore be selected according to bulk density, filling direction and powder flowability.

How Should the Dimensions Be Determined?

Step 1: Confirm the actual bulk density

Measure the lithium carbonate intended for packing and record:

• Product grade
• Batch
• Particle-size range
• Test condition
• Whether the sample was vibrated or compacted
• Density unit

Step 2: Calculate the theoretical material volume

Divide the target filling weight by the actual bulk density.

Step 3: Add structural and operational requirements

Consider:

• Filling and closing space
• Filling-spout and top-panel construction
• Space occupied by the baffles
• Bottom-discharge construction
• Pallet dimensions
• Warehouse and transport limits
• Maximum permitted filled height

Step 4: Produce and test a sample bag

Fill the sample with 1,000 kg of the actual lithium carbonate and record:

• Final filling weight
• Filled height
• Width around the middle
• Top and bottom dimensions
• Baffle extension
• Filling-spout closure
• Pallet fit after filling

What Data Should the Buyer Provide?

Conclusion

When selecting an FIBC for 1,000 kg of lithium carbonate, the rated load defines how much mass the bag is designed to carry, while bulk density determines how much space the material requires.

The 108 × 108 × 125 cm dimensions should be treated as a nominal reference. Accurate selection should begin with actual bulk-density data, followed by volume calculation, pallet and equipment matching, and a 1,000 kg sample filling test.