Bisbee daily review., 1920-03-14


 of Engineers H. l.. Kohlberg read a paper on the modern Teverberatory Iuinace. As much of the smelting at Douglas is done by means Of the re serberatory furnace and the concen- trates from the Sacramento Hill pro. Ject will necessarily be handled entire ly in the reverbeiator furnaces, a de jscriptiOn of that apparatus of gen cl a. interest here. Kohlbers said, in part:
 "Reverberatory smelling has had its greatest development Tn the last de. cade. Without gong into the history of this development an effort will be made to describe the apparatus. The furnace is essentially large chamber with walls and an arched roof made Of silica brick. It is 20 to 20 feet wide. , 100 to 175 feet long and about ten feet nigh from the floor to the lowest point of the arch at it's center. The bottom of the furnace consists of crushed sili. ba, made uniform by the application Of the greatest heat which the furnace will have to stand. The side walls of the furnace are from IS to 30 inches ,in thickness and the arched rool Is 3made of 20 inch silica brick
 Five to eight burners are placed in a row across the firing end Of the fur mace. Pulverized coal is the modern fuel. It is fed out of the fuel bin by feedscrews or similar devices which control the amount fed, and falls into the burner pipe where it is met by an air blast that carries the fuel into the furnace. The amount of air used for this purpose is usually only one-third or the total amount required for the combustion of the coal, the rest flow ing in through the port holes. actuated by the draft.
 The entire interior is filled with seething mass of flames, the tempera- ture in the first third of the furnace reaching 2500 to 270O degrees F., while near the uptake end it is about 2200 to 2300 degrees F. Above the whole length of the furnace is a sys- Item of charge tracks and the ore charge to be Smelted is brought from the roasters in closed cars to these tracks and dropped through pockets and pipes in the floor and through holes in the top Of the furnace and is made to lie along the side walls with in the furnace. In this manner every new charge is exposed to the heat of the furnace while the side walls are continually protected by the charge.
 "A reyerberatory furnace, fired and charged in this way, can smelt 500 to 800 tons of charge per day with a fuel consumption of about 100 tons of pull veriZed coal. The ore in the furnace is not smelted to copper but only to copper matte. Slag is the formation of a silicate Of iron, lime and other bases. These substances form the greater portion of the ore that is charged into the furnace, and their elimination is the result of the smelt- ing process. The slag is tapped at tho far end of the furnace, caught in Slag pots or granulated and thrown over the dump. There is seldom as much as one-half of one per cent of copper in the slag
 Ehe matte IS combination ot Sul- ,phur, copper and iron. and can be ex- Iplained as the solution of c copper and Nron sulphide in each other in varying amounts according to chemical formu la. It generally contains from p to 50 per cent copper. After enough matte has accumulated it is tapped from the side Of the furnace and made to flow into a ladlc which takes the liquid matte and dumps it into the converter, the apparatus by which the mat is converted into blister copper.
 "The. gases that pass out of the fur mace are carried through steam boilers so that the heat contained in them is conserved. This accounts for the sur