Assaying Silver Bullion

The apparatus which I shall describe in this paper has been in use for some time at the Silver Bullion Assay laboratory of the Pennsylvania Lead Company’s works, and has been found to give good results, and to be simple and convenient. Steam Bath.—This steam bath is shown by Figs. 1, 2, 3, and 4. … Read more

Mercury Assay Determination Method

The dry methods of assaying mercury-ores and other combinations of mercury all rest upon the volatility of this metal as a beginning. After the separation of the mercury in the form of vapor from the matrix upon which the assay is performed, the mercurial vapors are either condensed upon cold surfaces or received upon a … Read more

Silver Assaying & Cupellation

A great deal has been written of late regarding the loss of silver in assaying; very discordant results have been published by different writers, and much uncertainty exists concerning even approximate losses in a careful determination of silver, as represented by a fire-assay. In the present paper it has been the aim of the writer to … Read more

Electrolytic Assay

The analysis of refined copper is a subject of great importance, and has not received the attention it deserves. Copper metallurgists, therefore, will welcome the paper of Mr. Heath with satisfaction. The state of the art of the chemical analysis of copper has been such that consumers, if they could not afford to run any … Read more

Assay Determination of Arsenic & Antimony

Determination of Arsenic and Antimony Together: Instead of separating arsenic from antimony in the hydrochloric-tartaric acid solution which was finally obtained, dilute the solution to four times its volume; pass sulphuretted hydrogen to saturation; filter the combined sulphides on a 4 cm. filter (weighed and dried in weigh-bottle at 110° C.); wash with water, absolute alcohol, … Read more

Assaying of Silver

There has been considerable discussion of late as to the best method of determining the silver-contents of sulphides of silver resulting from the leaching of silver-ores, and also as to the relative merits of the crucible and the scorification method for the determination of the silver-contents of ores. Owing to the great depression in the … Read more

Phosphorus Determination Method

To have a complete text for a Method for the Determination of Phosphorus we must first discuss the interaction with other elements:  The Effect of Arsenic.—A question involving the temperature of precipitation of ammonium phospho-molybdate, which was brought to my attention some time ago, led to the following experiment: A known quantity of arsenic was … Read more

How to Assay Gold Jewellery Scrap

This standard prescribes the cupellation or fire assay method for assaying of gold in gold bullion, gold alloys, and gold jewellery and artefacts covered in IS 1417 “How to Assay Gold” Procedure. The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the edition … Read more

Fire Assay

Fire Assay is the most common technique for analyzing precious metals was developed and refined almost to perfection before the 15th century (5). Government, mining and smelting companies, private analytical laboratories, universities, and geochemical exploration companies depend on fire assay techniques to produce accurate results. Fire assaying has been adopted by the court system as … Read more

Fire Assay Furnaces and Furnace Equipment

The furnaces used in assaying are many in design, varying mainly with the kind of fuel used. The furnaces are classified as follows: (1) Pot furnaces, in which the assay is in direct contact with the fuel; (2) Muffle-furnaces, in which a muffle or receptacle containing the assay is externally heated. As the muffle-furnace is … Read more