How to Choose Refractory Bricks Used for Different Parts of Blast Furnace

1. Good corrosion/erosion resistance 2. High temperature performance 3. Longer service life 4. Stable structure 5. Thermal shock resistance

How to choose refractory brick used for different parts of blast furnace?

When choosing refractory brick used for different lining parts of blast furnace, we should follow some principles. The refractory lining of every part should fit the parts thermal current intensity, so that the lining can maintain previous vertebral shape and stability under the impact of strong heat flux. 

Here are some methods of selectingrefractory brick for sale for every part of furnace lining.
(1) Furnace throat. It mainly needs to withstand impact and abrasion of burden, so generally we use steel brick or water cooling steel brick for the furnace throat.

(2) The upper shaft. Plus the burden descent and ascending gas flow of scour and wear. Therefore, we should choose resistance to chemical erosion and abrasion resistance of refractory material, the most appropriate is high relative density brick, high density, high aluminum brick or phosphoric acid impregnated clay brick.

(3) The middle and lower part of nozzle refractory furnace and furnace bosh. The main mechanism of damage is thermal shock, high temperature gas scouring, and impact of alkali metals, zinc and carbon deposition, as well as chemical erosion of the initial slag. For those three parts, we should choose refractory materials with properties of thermal shock resistance, slag erosion resistance and erosion prevention. For blast furnace whose volume is smaller than 1000m3, we can use aluminum carbon brick. 

(4) Furnace bosh. Hot gas erosion and iron slag erosion are the main reasons for furnace bosh damage, this part of the heat flux intensity, refractory material refractory fiber felt life not long (as long as 1 to 2 months, as short as 2 to 3 weeks), generally used in refractory degree is high, load softening temperature is high and the volume density of refractory material, such as the high aluminum brick, alumina carbon brick. 

(5) Hearth tuber. This site is only in blast furnace of oxidation reaction area, high temperature from 1900 to 2400 DEG C, lining by damage caused by high temperature thermal stress. Composite brick masonry hearth tuyere zone is adopted by the modern blast furnace, material for high alumina, corundum Mo mullite; corundum and silicon nitride combined silicon carbide, useful also hot pressed carbon block. 

(6) The lower part and bottom of hearth. For those two parts, we use hot pressing small carbon brick, micro porous carbon brick, and hot semi graphite carbon brick with high thermal conductivity, good resistance to penetration, good resistance to chemical erosion, low porosity and micro aperture, as well as brown corundum or gray corundum brick used for ceramic cup.

How to Improve Free-opening Rate? -- Flow Guiding Sand

With the expansion of the production scale of the grade steel, the automatic free -opening rate of the ladle will affect the smoothly running of production and quality of the slab. The quality of the products have been improved by analyzing the influential factors and adopting appropriate counter-measures, such as using flow guiding sand which also named stuffing sand

or steel flow initiator.

Flow Guiding Sand is a kind of ladle slide nozzle filler which is successfully developed by Yilong Refractory in recent years, results show that ladle castable success rate of automatic free-opening rate can reach above 95 percent. There is no metallic inclusion in ingot surface, is a kind of ideal ladle slide nozzle filler. Steel flow initiator contains metal mixture whose weight is heavier and melting point is lower than molten steel. Before pouring we put it into the upper nozzle, using it to burn and cause the molten steel within the upper nozzle will not be solidified, to achieve the purpose of automatic pouring and avoid the problem of ingot inclusions. 

One research of Luoyang Research Institute of Refractory shows that the higher content of water in flow guiding sand, the lower compression strength of the sintered temperature product, the greater the apparent porosity, the smaller the bulk density, resulting the lower of ladle automatic opening and pouring rate.