Show LOW LO GRADE CRAD ZINC LINC ORE OR NOT DESIRED IN LEAD COPPER Since a tariff was placed on zinc ores a revival of the industry has taken place in a number of the old camps camps of the west In tho the early days when plenty of zinc blende blendo was found foud foudin in a mine that practically settled its it fate The smelters would not pay for tor forit forit it and would chr charge e for it Recently for new hOW processes have bave been adopted recovery recover of the tho zinc values the most successful ones installed in this state being beins located at the United States smelting plant near Midvale and the I plants at Park City An interesting I account of zinc zinc ne oro ore as a smelting I proposition is given giyen by Franklin Frankln GUI GUI- Guiterman terman lorman vice vice president sven of the American Smelting and Refining company which follows foos Associated with wih sulphides sulphide of pf lead and copper opper in our western ores is is nearly near ly always present zinc blonde blende Ores that carry less than 20 per cent zinc cannot as a rule in tho the present state of the art be treated at profit for tho the production of zinc even if i they be e previously pro pre subjected to a magnetic separation sep sept separation process Therefore in in order to extract the tho associated gold silver siver lead ead and copper values alues these ores are smelted copper in lead or copper blast furnaces furnaces fur fur- naces or in I Here I however the zinc is i thrown throw into the sla slag with other sla slag forming foring compounds Not only is it lost itself but it may occasion severe metal losses if it i be permitted to bo present beyond certain limits Thus in the roasting process it conduces greatly to the loss of silver as the volatilization of silver silveris siver is greatly y facilitated by its is association association I tion with wih other aUler volatile metallic compounds compounds com corn pounds such as zinc antimony and arsenic ar are ar- ar acme in in the presence of ore e Again in blast furnace operations zinc volatilizes as metallic zinc zinc only to in a measure in the upper tipper regions of the stack thus occasioning accretions which promote irre irregularity arity in the furnace work with attendant loss of control and incidental failure fiure to t do good metallurgical work e Finally with the passing of zinc zinc oxide into the slag a marked difference in its is physical characteristics takes place B Both t zinc oxide and silicate arc are practically infusible Hence these compounds raise the fusion point of I tho slag or at nt the usual temperature of blast furnace work render the slag I viscous so 80 that the metals or metallic compounds which it is intended to save Bavo do not separate from tho the slag as perfectly as they should and the mechanical mechanical mechanical me me- loss largely increases increases The i 1 loss of such zinc itself is not at nt all al a waste wate but occasions one I I When the percentage percentage- of zinc in inores inores inores ores rises rises sufficiently bi high h so that their mineral products may be bo successfully suc sac treated either ihor primarily or orby orby orby by means moans of ma magnetic separation with ib later lator zinc zinc recovery from the hi higher high h. h or er grado zinc zinc product so 80 obtained or orso orso orso so as to permit their treatment at once in in zinc furnaces for the tho production tion of spelter such ores ore become a source of Cf profit to the producer |