Refractories for converter

A P - S converter

Method in the production of copper, copper from sulfur to blister copper smelting process, for the most part, is in the process of converter, at present, a lot of countries around the world with large and medium-sized horizontal basic Bessemer, also called Pierce - Smith converter, referred to as P - S side blown converter, it is the main equipment, copper matte converting process method is simple, have the characteristics of simple operation, high efficiency, and thus has long been widely used in heavy non-ferrous metal smelting method process. The middle part of the converter body is provided with a port for feeding, smoke exhaust, slag discharge and copper discharge, and one side of the furnace body is provided with a row of air outlets along the horizontal direction for pumping compressed air or oxygen-rich air.

Different smelting factories, due to the converter type, size and matte taste different, the blowing operation is different, but the blowing principle is the same, are through the air or oxygen-rich air drum into the converter, stirring the melt in the furnace, and physical and chemical reaction with it.

Bof matte blowing can be divided into slag-making period and copper-making period, slag-making period is mainly regular, batch to inject hot matte into the converter, blast oxidation, add flux to make slag and regularly pour out slag, to obtain white matte containing more than 70% copper; Coppermaking period continue to blast oxidation, without adding flux, white matte will be blown into coarse copper.

Converter for intermittent operation, every week period, there are multiple operation, stop the wind feed the slag in the process of converting furnace temperature is 1200 ~ 1300 ℃, and stop feeding wind, pour crude copper slag, inhalation of cold air in the furnace, the temperature drops rapidly, generally when feeding furnace temperature drop in 300 ~ 500 ℃, temperature of converter is the fluctuation in 800 ~ 1500 ℃, so the converter lining refractory has good thermal shock resistance. During the operation of the converter, the high-pressure air is blown out through the tuyere, forming a strong agitation around the tuyere, and the high temperature melt has a strong scouring effect on the furnace lining. Therefore, the refractory materials of the converter in the tuyere area, especially the refractory materials in the tuyere area, should have good wear resistance. At the same time, converter smelting should also add some cold material and solid slag, quartz stone slag in blowing, slag main components FeO, CaO, SiO2 blowing slag type is from weak acid to strong alkaline, so the requirements of furnace lining has good anti-alkaline slag performance.

For the integrity of tuyere and the accuracy of tuyere position, the tuyere bricks are built as a whole with solid bricks at present, and then the air hole is drilled with special drill. The material is made of molten grain and combined with magnesia-chrome bricks or directly combined with magnesia-chrome bricks. The tuyere area is also made of the above materials. The cylinder and end wall are made of high quality magnesia chrome brick or magnesia brick in the slag line part. Brick laying at the furnace mouth is the weakest part of structural strength, especially the junction between the furnace mouth and the circular cylinder, which is difficult to master because of the complex shape, large amount of brick processing and many brick joints. Furnace is the feeding, slag pouring, smoke exhaust channel, process operation is very frequent, temperature changes frequently, copper slag splashing, flue gas erosion, the impact and wear of furnace cleaning machinery, CuS2, SO2 erosion is very serious, lining working conditions are extremely harsh. Therefore, measures should be taken in the structure to reduce the brick type as far as possible and reduce the weak links in the structure; In the material selection, all the direct combination of magnesia-chrome brick, improve the overall life of furnace body.

The inner lining of converter is mainly magnesia-chrome refractory material. The magnesia-chrome brick has good resistance to cold and heat, good wear resistance and good resistance to alkaline slag. The vulnerable parts of the lining are mainly tuyere and tuyere area, furnace mouth and end wall and so on. Especially the tuyere and tuyere area, the use of the most demanding conditions, but also the most vulnerable parts. Solving the service life of refractories used in tuyere and tuyere area can not only reduce the corrosion loss of the whole converter lining, but also greatly increase the furnace life of the converter.

B Improved P-S converter

The traditional P-S converter has some obvious shortcomings, such as copper converter in feeding and dumping products, furnace gas escape, pollution of the environment; The intermittent operation makes the concentration of SO2 in the exhaust gas fluctuate greatly, which complicates the control of the process of recovering SO2 for acid production. In view of the above problems, people have made improvements to it. The main improvement furnace type is:

(1) siphon converter. Siphon converter adopts a special inverted U-shaped siphon flue from which the smoke is discharged. Because the siphon flue can be rotated with the furnace body, the converter and flue can be directly connected when the furnace is rotated to any position. Its main advantages are: the flue gas will not be diluted, the concentration of SO2 up to 11%; Non-stop wind can add solid or liquid materials; The air supply rate is high, the smoke volume is stable, and it will not cause the smoke escaping pollution of the environment due to the wind tilting; Sprinkling less, do not need to clean the furnace mouth; Since there is no hood and flue at the furnace mouth, the melt sample can be obtained from the furnace mouth with a spoon without obstruction.

(2) Teniente Converter

The Teniente Modified Converter, or TMC Converter, was first produced and operated in 1977 at the Caletones smelter in Chile. TMC converter is a long horizontal converter with an inner diameter of 5m and a length of 22m. About the same amount of copper and sulfur (taste 48%~50%) and copper concentrate are continuously self-heated melting and blowing in TMC furnace filled with oxygen-rich (containing 30%~34% O2) air to produce high grade copper and sulfur containing 75%~78% copper and slag containing 4%~6% copper. The slag is returned to the reflecting furnace for treatment, and the high grade copper and sulfur are sent to the P-S converter to be smelted into coarse copper by oxygen-rich air. By 1995, the TMC method produced 800kt/a copper, accounting for 9.3% of the world's crude copper production at that time, ranking first among all kinds of molten pool smelting methods, and there are 7 factories in Latin America. Tenient converter technology aims at simultaneously carrying out copper and sulfur blowing and self-heating smelting of copper concentrate in the reactor to produce flue gas with high concentration of SO2 (10%~20%) and high grade of copper and sulfur or white copper. During blowing, wet concentrate with water content of 7%~8% and siliceous flux are continuously added into the furnace through the Gall gun. Dry concentrate (water content 0.2%~0.5%) is continuously injected by the specially designed tuyere, oxygen-rich air (28%~33%O2) is continuously pumped into the conventional tuyere, copper sulfur (containing about 75% CuCu) and slag are intermittently released through their respective water-cooled discharge outlets.