Show new process of cinnabar Cinn ibar ore reduction written for the mining review lewis and dark clark fair portland oregon aug 25 few exhibits at the lewis and dark clark fair are attracting abre attention than that of the Black butte quicksilver mining company in in the mining and metallurgy building besides the extensive display of ores from these mines which are located in Black butte camp lane county oregon W B dennis manager of the mines also has on display a working model of a new quicksilver reduction plant of which he is the maker this cinnabar roasting plant is the result of years of hard work and study on the part of mr dennis and its perfection seems destined to give it a prominent and lasting place among all districts of the world where cinnabar is mined that the dennis roasting furnace will prove a success is is now well demonstrated beyond a doubt and the company is at work installing a ton plant on its properties the Black butte mines are the most extensively developed of any quartz mines gold or otherwise in oregon having some feet of underground work done and thousands of tons of ore uncovered having this vast body of ore it remains but a question of reduction for a long period the continuous roasting furnaces of the type used on the cinnabar mines of california were tried but the cost of coke and the other items of expense connected with quicksilver reduction made the methods of the old style furnaces unavailable for the treatment of oregon cinnabar A furnace of a new type was necessary and the plant now perfected meets all the requirements of low grade cinnabar ore treatment in the old scott continuous furnace which is the common furnace used in the mercury mines of california the ore is charged at the top of a brick structure forty feet high passing by degrees from one apron to another until the slag floor is reached the heated blast ascending through the ore in its descent mercury is in the course of ore fusion the gas carrying the gasua ted mineral being conducted to a condensing chamber where the mercury is precipitated in several chambers at the bottom of these condensing chambers of the 7 T H E D E N N 15 F ti R N aa E 1 I wak N 7 0 ORE d J E n 7 S x al Z mix 40 scott furnace is found heaps of soot impregnated with mercury and this mass must be worked over by mechanical or hand methods to extract the metal all of the mercury could not be worked out of the soot in this way and in efficient smelter practice it is necessary to briquette the residuum and recharge it into the furnace the cost of hand extraction bri and re charging where a resinous fuel was used as in oregon became a heavy item of expense primarily mr dennis sought to obviate the soot to do this he was compelled to effect absolute combustion of his fuels fed into the firebox and the organic matter and sulphur derived from the ores roughly he says that this has been achieved by manu fracturing fac turing a gas from the wood this to combustion chambers distributing 8 and subjecting t the ores to a roast under high temperature tempe ratu which is recuperated and intensified by d de gre grees es the draught is introduced i into n tt th top of the ore charge instead of at t the ahto hot bot e torn tom in the as scott furnace and the highest temperature is had at the point of exit rather than where the draught first strikes the ore condensation is accomplished by bv the same general control of the blast with the scott furnace as there is no successful gas generator using fuel in smelter practice many inventors have striven to attain this end that mr dennis has been successful is attested by the temperature of his experimental furnace in no I 1 roasting zone he holds the temperature at about degrees pahren fahren heit and in no 4 zone which is the last in the experimental plant the temperature attains 1200 to 1400 degrees in the aylin adrical flue chamber leading the gases from the roasting zones combustion is further advanced and the temperature raised again so that the temperature of the blast at the P point of final exit attains 1600 to 1800 degrees of the capacity of the furnace there is more to be told than this relating to the temperature in the scott furnace the best time made in california is a twenty four hour roast the extreme being forty eight hours and the mean thirty six hours the time that will be required with the new furnace perfected by mr dennis has not been reduced to the minimum yet as it is along this line that the experiment work is being conducted now the longest period yet required has been eight hours for a charge which is but one third of the minimum with the scott and about one quarter of the average time required this increases the capacity of the furnace accordingly giving it from three to four f our times the tonnage that can be put through the scott most remarkable of conditions attained however is the complete combustion cfall of all gases there are no more deadly fumes in ift all metallurgy than that coming from a cinnabar roast where the utmost care is is not observed it has been the experience of mankind that workmen suffered grievously mr dennis has a furnace that so thoroughly separates all gases and minerals that a roan man can hold his nostrils in the draught issuing from the top of the stack for an hour breathing deeply all the time and not feel the slightest ill effects there is no smoke color and no fumes to be detected by smell |