There have also been introduced processes in which the chlorine is generated in the chloridizing vat, the reagents used being dilute solutions of bleaching powder and an acid.
The supernatant liquid is led into settling tanks, where a further amount of "gold is deposited, r and is then filtered through sawdust or sand, the sawdust being afterwards burnt and the gold separated from the ashes and the sand treated in the chloridizing vat.
This is imperfectly accomplished, in the wet way, by cupric and cuprous chloride solutions, but completely so, in the dry way, by roasting with salt (chloridizing roasting).
According as a preliminary chloridizing roast has or has not been given, the process is classed as roast-amalgamation or raw-amalgamation.
In a chloridizing roast chlorine produces its effect as nascent chlorine or gaseous hydrochloric acid.
