Refractory Products For Nickel-smelting

August 29, 2018

Refractory products used in masonry nickel industrial furnaces.

In the case of nickel smelting, first sintering ore from nickel sulfide or nickel concentrate to obtain sintered ore and then the sinter is smelted into low-ice nickel, which is then blown to form high-ice nickel, and finally electrolyzed into metallic nickel. The thermal equipment used in this process mainly includes a carbon baking furnace, a melting furnace, and a blowing furnace . The operating temperature is generally around 1500 ° C, and the furnace lining mainly bears the effects of chemical erosion, erosion, thermal stress and mechanical damage of the material. Usually clay bricks, high alumina bricks and alkaline refractory bricks are used for masonry. The service life varies depending on the type of furnace, raw material conditions and smelting process.

Refractory products for steel making converter

The furnace is cylindrical and can be divided into horizontal and vertical. Horizontal converter with nominal loading capacity of 50t is widely used in China. It has a diameter of 3.66m and a length of 7.1m. There are no 22 air holes in the converter. The working temperature during blowing is 1350-1500°C, and the blowing time is about 7-10h per furnace.

The tuyere and tuyere area are the most serious in the damage of refractory material in nickel converter lining. When magnesium chrome bricks are used to build the tuyere and tuyere area, the life expectancy is only about 18 times.In order to improve the lining life of nickel-smelting converter, a magnesia-chromium tuyere brick was developed by our country in the late 1980s, which can resist erosion, erosion and penetration of iron-silicon slag and sulfide melt. Its physical and chemical properties are as follow: MgO 50%-54%, Cr2O3 25%-32%, AL2O3 8%-12%, Fe2O2 24%-8%, Sio2 < 1.5%, Cao < 1.5%, porosity 21%, bulk density is 3.0-3.1g/cm3, the cold crushing strength is greater than 60 MPa, the high temperature bending strength at 1400 °C is 11 MPa, and refractoriness under load from 1750 °C.

The magnesium-chrome tuyere brick and the semi-recombined magnesia chrome tuyere brick (performance MgO 60%, Cr2O3 21%, Al2O3 6%, FeO 7%, Sio 2.3%, porosity 15%, bulk density 3.26g/cm3, cold crushing strength 45MPa, and refractoriness under load 1730°C) were used to lay in the tuyere and tuyere area of 50 t converter, the life of the converter lining is significantly improved, and the service life is more than 50 times. Fully synthetic magnesia-chrome bricks, pre-reactive magnesia-chrome bricks and aluminium-chrome slag bricks have been used in a 10 t nickel-smelting converter in China. It has achieved good results.