Refractories for copper refineries

Coarse copper refining furnace has fixed reflector furnace and tilting converter two kinds. These two types of furnace are basically the same as the reflector and converter described above. Most of the domestic use of fixed reflector refining, furnace lining using magnesia brick, magnesia aluminum brick or magnesia chrome brick masonry. The top of foreign refining reflector is constructed with unburned magnesia-chrome brick, magnesia-chrome brick or directly combined magnesia-chrome brick, the wall of furnace is made with magnesia-chrome brick, the lower part is made with directly combined magnesia-chrome brick and common magnesia-chrome brick, and the bottom of furnace is made with silicon brick.

A Copper refining reflector

The structure of copper refining reflector is basically the same as that of smelting reflector, but the size is smaller. The furnace body is generally 4~8m, the width of the furnace is 2.4~3.1m, the height of the furnace from the bottom to the top is 1.6~2.5m, the depth of the melting pool is 0.6~0.9m, and the capacity of the melting pool can be up to 140t. Refining reflector has the advantages of simple structure, easy operation and wide adaptability to raw material combustion, but its disadvantages are low thermal efficiency, poor operating environment and working conditions.

Refining reflector production is still periodic operation, the charge is loaded from the side wall door, the use of heavy oil or coal as fuel, melting period operating temperature of 1300~1400℃, furnace flue gas temperature of 1150~1300℃. The purpose of the refining process is to remove impurities such as zinc, tin, iron and lead from the crude copper. In the REDOX phase of refining, the refractory materials of the furnace bottom and wall are also involved in the production process. The acid lining enables the oxides of iron, zinc, and cobalt to slag well and produce silicate (the use of acid lining is especially reasonable in the case of high lead content). In order for lead to form silicate, an acid flux must be used when an alkaline lining is used. In an alkaline lined furnace, nickel, arsenic, and bismuth are more completely removed because magnesium oxide can decompose the arsenic complex of nickel and copper, which is difficult to convert to slag, and form arsenates with these compounds.

B Rotary refining furnace (anode furnace)

In recent years, with the technical progress of copper smelting process and the expansion of production scale, copper refining furnace also has a new development, large smelters have begun to use rotary refining furnace or tilting refining furnace.

Rotary refineries are suitable for refining crude copper, allowing only 20%~25% of solid material to be added. Refining operations for feeding, oxidation, reduction, casting, the product for the anode plate, so rotary refining furnace is also known as rotary anode furnace. Rotary refining furnace is a cylindrical furnace that can be rotated. An opening is arranged on a cylindrical furnace body for charging and discharging copper. The opening is provided with a furnace cover, and a small amount of tuyeres are arranged on the side of the furnace cover. The advantages of rotary refining furnace are less heat loss, good airtightness and improved operating environment; High degree of mechanization and automation, flexible operation, low labor intensity. The disadvantage is the high investment in equipment.

The furnace temperature of rotary refining furnace is higher than 1350℃ (casting period), and the highest can reach 1450℃ (oxidation period). Because the furnace body is rotating, there is no fixed slag line in the furnace, the erosion of slag and the erosion of molten metal almost occupy more than 2/3 of the furnace inner surface. Therefore, the content of Cr2O3 in the lining of magnesia-chrome brick is generally required to be greater than 22%, and the requirements are higher at the reoxidation and reduction port and the copper outlet, and the direct combination of magnesia-chrome brick or electric fusion is often used to recombine magnesia-chrome brick. At present, the refractory materials used in rotary anode furnace have been all domestic refractory materials.

To sum up, the high erosion parts such as reflection furnace, converter, anode furnace and flash furnace used in copper smelting industry are mainly high quality magnesia-chromium refractory materials, and a small amount of magnesia-aluminum brick or magnesia-aluminum brick is also used in some non-main parts. High quality magnesia-chrome refractories mainly have the following kinds: direct bonding magnesia-chrome refractories, electric fusion rebonding magnesia-chrome refractories, half rebonding magnesia-chrome refractories, melting cast magnesia-chrome refractories, etc.