Services to the sciences since 1924
Please be advised that the supplier of our Boiling Stones has been unable to provide a definitive date as to when they may be available. Until further notice, we only have the 8 - 12 Mesh Boiling Stones and a limited quantity at that. Please call for availability.
Porous grainy structure insures: "a myriad of sites for ebullience", not just corners; large contact area that cannot be worn smooth; light weight that promotes stirring action and heat distribution
The lower density also means economy-more pieces per pound (See Table)-lower cost.
Fused silica grains, 93.4% pure. (Not just fractured minerals having smooth cleavage planes).
Average Chemical Composition
Insoluble - Porous - Effective
Being insoluble and porous, Cargille Boiling Stones are excellent as catalyst and reagent carriers for analytical procedures and production processes.
Cargille Boiling Stones are recommended for Kjeldahl, Folin-Wu and other procedures where superheating may occur. If trace alkalinity is a concern, rinse Boiling Stones a few times in distilled water and dry before using.
The "Why" of Bumping
Bumping is caused by: dissolved gases, local superheating, bringing to a boil too quickly, suspended solids; all contribute to rapid formation of large vapor pockets that explode to the surface.
Bubble formation shock can cause physical damage and create a safety hazard. Surface splash carries over constituents that can greatly "louse-up" analytical results.
Cargille Boiling Stones provide innumerable points on which occluded gases and vapor are thrown out of solution in fine streams of minute bubbles. The resulting convection currents distribute heat and promote gentle boiling.
Porous "stones", having the desirable tendency to move with the bubbles, contribute to the stirring action (1).
(1) Charlett, S.M. (1964) Notes on "Bumping". Laboratory Practice, 13 (12), 1204-1207
How Many Boiling Stones?
Very few. But enough for the lifting action to always leave some on the bottom
Some Specific Applications
1. Determining nitrogen by the Kjeldahl method-in distillation stage and digestion. Where the sample contains oil, the froth is spread out evenly and is therefore restrained from climbing the neck of the flask.
2. Evaporating ethereal extracts of fat. Several stones in the flask will prevent oil from creeping over the rim.
3. When boiling soap solutions after acidulation to clear off fatty acids, sudden spatter can be eliminated.
4. When boiling acetylated oils with water to eliminate acidity, bumping can be completely avoided.
Available in Assorted and Selected Mesh Sizes
Boiling Stones Price Schedule
All prices are subject to change without notice. Please contact us to confirm prices.