Condenser
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The condenser also is made of stainless steel and it contains several (12) small pipes fitted parallely through which solvent vapour is passed.
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By circulating cold water in the condenser continuously the solvent vapour is condensed and it is collected for recycling.
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The heating of the evaporator is continued till about 90% of the solvent is recovered by condensation which may take about 30 hours.
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The remaining 10% of the solvent containing all the aromatic oil and waxy material is transferred to vacuum distillation unit where the complete removal of the solvent is effected, and the concrete is left in the still in the form of molten wax.
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Here also the still should not be heated directly.
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The heating should be done on a water bath.
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Since vacuum has been created into the still, the solvent evaporates quickly at lower temperature which is condensed in the condenser and collected for recycling.
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The heating should be continued till the last traces of hexane are removed.
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The operation can be stopped when there is no condensation of hexane vapour in the condenser.
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After the complete removal of the solvent, a semi-solid was like brown substance is left in the still which is the jasmine concrete of commerce.
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The material when it is hot is transferred to the container in which it has to be stored, when cooled it solidifies and transfer to other containers may be difficult.
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The concrete can be stored in glass or aluminium containers.
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Last modified: Friday, 8 June 2012, 10:01 PM