Page 106 - QRedition5.0 062021

Quality Requirements Edition 5.0 European Enamel Association

Required reagents: 8.5.1 Testing of setting agents and other accessory materials
Methylene blue solution (I)

Dissolve 3.2 mg methylene blue in 500 ml distilled water of about 70 C. Put Purpose and scope
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this solution in a 1000 ml measuring flask and fill up at 20 C with distilled water. Testing of setting agents and other accessory materials can mostly be done in the
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laboratory of the enamelling shop. The various analytical processes presuppose training
Methylene blue solution (II) and experience.
Dissolve 1.6 g methylene blue in 500 ml distilled water of about 70 C. Put this
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solution Normally, setting agents are genuine or chemically pure chemicals supplied by the chemical
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in a 1000 ml measuring flask and fill up at 20 C with distilled water. industry with their final quality control.

6n sulphuric acid It is substantial for the processing plant to store the setting agents according to their
Mix 167 ml concentrated H SO (Density 1.84) with 700 ml distilled water and fill up storage specifications. Some of them, e.g. sodium aluminate, are hygroscopic. That is to
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to 1000 ml with distilled water. say, they adsorb water, so that the agent cannot be used for enamelling.

In case of doubt about the correct storage of accessory materials, suppliers or
manufacturers should be contacted for the
corresponding specifications.

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