ASTM D721 Standard Test Method for Oil Content of Petroleum Waxes

Get Certified ASTM D721 Petroleum Wax Oil Content Testing

ASTM D721 testing enables the petroleum-wax manufacturer, refiners, suppliers, and quality-control personnel to establish the oil content of applicable wax materials. Technicians isolate and process a sample of petroleum wax that is representative of the sample and conduct the necessary dissolution, cooling, separation, and recovery operations. They employ calibrated equipment to determine the necessary amounts and document pertinent test conditions. The measured values are then used to determine the amount of oil in the sample of tested wax. The results can be used for product comparison, production monitoring, wax-quality evaluation, and quality control activities.

• Material Type: Petroleum waxes and applicable wax products for which oil-content determination is required.
• Purpose: Quantification and evaluation of oil present in petroleum wax.
• Property Measured: Oil content of the tested petroleum wax.
• Method: Testing involves preparing and dissolving a representative wax specimen, separating the wax and oil-containing portions under specified conditions, and using the required mass measurements to calculate the oil content.
• Result: Oil content is generally reported as a mass percentage (%) of the tested sample.
• Test Limitations: Results apply to the specified petroleum wax materials and test conditions and may be affected by sample handling, solvent purity, separation efficiency, and recovery procedures.
• Environmental Conditions: Temperature control during dissolution, cooling, and separation can affect the test process and should be maintained according to the applicable procedure.
• Applications: Petroleum-wax quality control, product specification evaluation, production monitoring, material comparison, refining-process control, and wax-product development.

What are the uses of ASTM D721 testing?

ASTM D721 is a test method that can be used to identify if a petroleum wax contains the correct amount of residual oil for its intended uses. Oil content may affect the properties of a wax, including hardness, melting range, consistency and end-use. Technicians and analysts rely on the results to assess the consistency of production and to detect batch to batch differences in wax. The test is also used for product specification and quality control. The test helps to:

• Determine the oil content of petroleum waxes.
• Evaluate wax purity and composition.
• Compare different petroleum wax products.
• Monitor production consistency.
• Identify changes in wax-processing conditions.
• Support product specification evaluation.
• Assist refining and manufacturing quality control.
• Support material development and product evaluation.

Which Materials Can Be Tested According to ASTM D721?

ASTM D721 is intended for petroleum wax materials in which the residual oil content needs to be determined. Technicians select representative samples from the wax product and prepare them according to the applicable procedure. The method can support evaluation of petroleum waxes from different production sources and processing conditions. Analysts can use the results to compare materials with different levels of residual oil. The method may apply to:

• Petroleum Waxes: Evaluates applicable petroleum wax materials for oil content.
• Refined Wax Products: Supports evaluation of waxes produced through applicable refining processes.
• Different Wax Grades: Allows comparison of oil content between applicable wax grades.
• Production Samples: Supports testing of representative wax samples from production batches.
• Quality-Control Samples: Helps monitor variations in oil content during manufacturing and refining.

Why is ASTM D721 testing important?

Oil in petroleum wax can alter its physical properties, appearance, consistency, and application. The range of values may be due to differences in the efficiency of oil refining, the process conditions, or product characteristics. ASTM D721 is the standard method for determining the oil content in applicable petroleum waxes. This method enables the evaluation of representative samples in controlled conditions by technicians and analysts. The results are used by the manufacturers to track product consistency, to compare wax grades, to refine the product, and for quality control and material specification.

ASTM D721 Testing Process and Data Collection

Technicians identify the petroleum wax and prepare a representative test specimen. They determine the required initial specimen mass using calibrated weighing equipment. The technicians dissolve the wax according to the specified procedure and control the applicable test conditions. They then cool and process the sample to separate the wax and oil-containing components. Technicians recover the required material and determine the relevant mass measurements. They record the specimen identification, mass data, test conditions, and applicable observations. Analysts use the recorded measurements to calculate the oil content and report the results as required by the selected procedure.

Common Challenges and Troubleshooting

ASTM D721 results can be influenced by sample contamination, inaccurate weighing, incomplete dissolution, temperature differences, incomplete separation, loss on filtration and/or recovery, and contamination of the solvent. Technicians should collect representative samples and adhere to the necessary handling and separation. They should check weighing and temperature equipment condition and calibration prior to testing. Reliable and comparable results for oil content can be obtained through consistent sample preparation, accurate weighing, controlled separation conditions, and careful recovery of materials.

• ASTM D721 provides an oil-content result for the tested petroleum wax.
• Analysts generally express oil content as mass percent.
• Technicians record specimen and recovered-material masses in appropriate SI units, such as grams (g).
• The report includes the petroleum wax identification and applicable sample information.
• Technicians document relevant test conditions and observations.
• Analysts can compare oil-content results between applicable wax grades or production samples.
• Accurate sample preparation, controlled separation, careful recovery, and calibrated weighing equipment support reliable and comparable results.

Link to ASTM D721