ASTM D7280 Test Method for Quinoline-Insoluble (QI) Content of Tar and Pitch by Stainless Steel Crucible Filtration

Scope: 

ASTM D7280 test method determines the quinoline-insoluble matter (QI) in tar and pitch using a stainless steel filtering crucible and a filtration membrane. It is used to assess and characterize the tar and pitch. Furthermore, it ensures that shipments and sources of supply are consistent.

Test Procedure: 

In ASTM 7280, the samples are mixed thoroughly. At atmospheric pressure, the samples are dehydrated using a simple side-arm distillation apparatus similar to the one used in Test Method D850. The water content of the tar is determined by Test Method D95 as an alternative to dehydration. Afterwards, the working sample is prepared and preserved for 24 h. A single membrane is placed over the threaded part of the ring onto the support disc with forceps. The barrel is attached to the ring assembly and tightened, the weight of the crucible and CAFA is measured and followed by heat treatment of the  beaker containing quinoline. In the filter flask, the filter tube is placed with an adapter, and with the previously prepared and tarred crucible. Sufficient amount of quinoline is added to the crucible to wet the diatomaceous earth filter aid thoroughly. The hot quinoline-pitch mixture is then poured into the crucible, while the diatomaceous earth filter aid in the crucible is still wet, without disturbing the mat. To drain the contents completely the mixture is stirred, but not as so the insoluble material on the filter seems dry.  Each wash should pass almost completely through the filter before the next is added. After the final quinoline wash has passed through the filter, the crucible is filled with toluene and washed with a total of 75 to 100 mL of toluene using suction.  Full suction is maintained for a minimum of 5 min after the acetone wash. The filtering crucible is then placed in the drying oven at 110 ± 5 °C and dried to a constant weight of 61 mg. Finally, weigh and record the weight of the filtering crucible and its contents.      

Data: 

Quinoline-Insoluble (QI) Content of dry basis is obtained by,

Conclusion:

ASTM D7280 standard test method covers the test for quinoline-insoluble matter (QI) in tar and pitch.