Selecting Bulk Bags Based on Material Density

Material density is a key parameter when selecting bulk bags. This article details how to select the appropriate bulk bag based on material density.

What is Material Density?

Bulk Density

Bulk density refers to the mass per unit volume of loose materials in their natural piled state.

Unit: kg/m³ or g/cm³

Formula:

Bulk Density = Material Mass / Piled Volume

Bulk Density vs. True Density

Concept	Description
True Density	Density of the material itself
Bulk Density	Density including voids
Relationship	Bulk Density < True Density

Common Material Density Table

Chemical Industry

Material	Bulk Density (kg/m³)
Urea	700–800
Compound Fertilizer	800–1000
Diammonium Phosphate	900–1000
Potassium Chloride	1000–1200
Ammonium Sulfate	900–1100
Soda Ash	500–600

Plastics

Material	Bulk Density (kg/m³)
PE Granules	500–650
PP Granules	500–600
PVC Granules	600–800
ABS Granules	550–650
Nylon Granules	600–700
PET Granules	700–900

Food

Material	Bulk Density (kg/m³)
Flour	500–700
White Sugar	800–900
Salt	1000–1200
Rice	750–850
Wheat	700–800
Corn	700–800
Soybeans	700–800
Starch	500–700

Building Materials

Material	Bulk Density (kg/m³)
Cement	1200–1600
Lime	900–1200
Sand	1400–1600
Gravel	1500–1800
Gypsum Powder	800–1000
Talc Powder	800–1000

Minerals

Material	Bulk Density (kg/m³)
Iron Ore Powder	2000–2500
Copper Ore Powder	1800–2200
Zinc Ore Powder	1500–2000
Bauxite	1200–1500
Quartz Sand	1400–1600
Carbon Black	300–500

Density and Bulk Bag Selection

Calculation Formula

Required Volume = Loading Weight / Material Density
SWL ≥ Loading Weight

Selection Steps

1. Determine material density
2. Determine loading weight
3. Calculate required volume
4. Select appropriate specification

Density Classification Selection Guide

Low-Density Materials (< 700 kg/m³)

Characteristics:

• Large volume, light weight
• Requires larger volume

Recommendation:

• Large volume bulk bags
• Pay attention to size limits

Example Materials:

• Plastic granules
• Carbon black
• Flour

Medium-Density Materials (700–1200 kg/m³)

Characteristics:

• Moderate volume
• Wide range of selection

Recommendation:

• Standard specification bulk bags
• General purpose

Example Materials:

• Fertilizer
• Grain
• Sugar

High-Density Materials (> 1200 kg/m³)

Characteristics:

• Small volume, heavy weight
• Requires high-strength bulk bags

Recommendation:

• High SWL bulk bags
• Reinforced design

Example Materials:

• Cement
• Ore powder
• Salt

Density and Volume Reference Table

1000 kg Loading Capacity

Density (kg/m³)	Required Volume	Recommended Size
500	2.0 m³	120×120×140 cm
600	1.67 m³	110×110×140 cm
700	1.43 m³	105×105×130 cm
800	1.25 m³	100×100×125 cm
900	1.11 m³	95×95×125 cm
1000	1.0 m³	90×90×125 cm
1200	0.83 m³	90×90×105 cm
1400	0.71 m³	85×85×100 cm
1600	0.63 m³	80×80×100 cm
1800	0.56 m³	80×80×90 cm

Comparison of Different Loading Capacities

Loading Capacity	Density 500	Density 800	Density 1200	Density 1600
500 kg	1.0 m³	0.63 m³	0.42 m³	0.31 m³
750 kg	1.5 m³	0.94 m³	0.63 m³	0.47 m³
1000 kg	2.0 m³	1.25 m³	0.83 m³	0.63 m³
1500 kg	3.0 m³	1.88 m³	1.25 m³	0.94 m³
2000 kg	4.0 m³	2.5 m³	1.67 m³	1.25 m³

Handling Special Situations

Uncertain Density

Handling Method:

1. Sample measurement
2. Refer to similar materials
3. Select larger specifications

Large Density Variation

Handling Method:

1. Calculate SWL based on maximum density
2. Calculate volume based on minimum density
3. Reserve safety margin

Mixed Materials

Handling Method:

1. Measure density after mixing
2. Or estimate based on main components

Density Measurement Methods

Simple Measurement Method

Tools:

• Container with known volume
• Weighing equipment

Steps:

1. Weigh empty container
2. Fill with material and weigh total weight
3. Calculate density

Formula:

Density = (Total Weight – Empty Container Weight) / Container Volume

Professional Measurement Method

Use a bulk density tester and measure according to standard methods.

Selection Examples

Example 1: Urea Packaging

Known:

• Material: Urea
• Density: 750 kg/m³
• Loading Capacity: 1000 kg

Calculation:

Required Volume = 1000 / 750 = 1.33 m³

Selection:

• Size: 100×100×135 cm
• Volume: 1.35 m³
• SWL: 1000 kg

Example 2: Cement Packaging

Known:

• Material: Cement
• Density: 1400 kg/m³
• Loading Capacity: 1500 kg

Calculation:

Required Volume = 1500 / 1400 = 1.07 m³

Selection:

• Size: 95×95×120 cm
• Volume: 1.08 m³
• SWL: 1500 kg (Requires high SWL specification)

Frequently Asked Questions (FAQ)

Q: How to obtain material density?

A: You can consult material technical data sheets or perform sample measurements. We can also provide reference data for common material densities.

Q: What is the relationship between density and bulk bag cost?

A: High-density materials require high SWL bulk bags, which tend to be relatively more expensive; low-density materials require large volume bulk bags, which may have larger dimensions.

Q: How to handle density variations?

A: It is recommended to select based on the worst-case scenario and reserve a safety margin.

Conclusion

Correctly understanding material density is key to selecting the right bulk bag. If you have any questions, feel free to contact us for selection support!