Cause of carbon containing refractories not suitable for using in the Nickel Converter.

Due to the poor wettability of molten slag and graphite, graphite to refractory oxides can greatly reduce the infiltration depth of slag refractory material, thereby reducing the thermal spalling and flaking refractories. Therefore, in the iron and steel industry especially some intermittent production equipment such as hot metal pretreatment tank (or bucket), oxygen converter, electric furnace, ladle, extensive use of carbon containing refractories, and achieved good results. Naturally want to carbon containing refractories used in copper, nickel converter, but the effect is not ideal. The former Soviet Union, Japan and China have in copper or Nickel Converter tried MgO – C, C, but the effect is not ideal.

Why the carbon containing refractories in the iron and steel industry especially the effect of oxygen converter steel making is very good, but in the smelting of copper, nickel converter is not ideal?

Metal melt the iron and steel industry is the Fe.c melt. The blast furnace gas contains large amounts of CO, carbon in liquid iron at or near saturation; natural, blast furnace, hot metal pretreatment tank available carbon and carbon containing material. The important task of oxygen converter steel making is to reduce the carbon in liquid iron, steel will precipitate a large number of CO gas, in iron making, converter, oxygen pressure is very low.

Copper or nickel converter blowing to the matte or ice nickel (nickel matte, ice is Cu – Fe – S or Ni – Fe-s sulfide melt) FeS oxidation in the melt of FeO, into the molten slag.

As long as the partial pressure of CO is less than CO equilibrium partial pressure 5.02 × 105 kPa, carbon refractories in carbon will be oxidized. While copper, nickel converter, CO partial pressure is small, far more than the CO equilibrium partial pressure 5.02 × 105 kPa much smaller; thus in refractories containing carbon, oxidation tendency is very large, it is easy to be oxidized. So the copper or Nickel Converter with carbon containing refractory lining, the use effect is not ideal.

The development prospects of refractory ceramic fiber

Due to rising energy prices, fuel costs will become a bottleneck for the development of ceramic industry control, energy conservation is more important. The more people concerned about the furnace heat loss and, some directly in the original lining layer adhered to the refractory ceramic fibers to enhance thermal efficiency. In the add must be before the kiln wall obvious cracks or spalling parts repair. But the insulating refractory bricks and refractory fiber can not be arbitrary abuse. So far as the basic oxygen steelmaking furnace,

cement rotary kiln lining, due to the high temperature chemical erosion, temporarily can not be used for lining of fiber.

For the continuous heating equipment such as ceramic tunnel kiln, have realized the refractory ceramic fibers used as continuous heating equipment lining, according to some reports, the rapid push board kiln and tunnel kiln energy saving effects of the refractory ceramic fibers are very significant. Especially the ultra high temperature heating, such as sintering temperature in the furnace is 1538 ℃ - 1649 ℃, the best energy saving effects of the refractory fiber.

At present, the ceramic kiln equipment in Europe and America and Japan using all ceramic fiber lining. Not long ago, Japan will gas tunnel kiln decomposition such as carriage structure of segmented manufacturing, then to porcelain factory construction site assembly, all of this is due to the use of ceramic fiber material, greatly saves the cost of more convenient because of the kiln. To promote the study of effect of energy-saving ceramic fiber material modification products from the ongoing.

Refractory ramming material and its characteristics

Refractory ramming material is bonded granular material consists of very high proportion and the proportion of very low and other ingredients, even all the grain, powder material, to the strong pound bulk material to fight the way construction.

Because the ramming material is mainly used for direct contact with the melt, the grain, powder material must have high volume stability, compactness and erosion resistance, used for induction furnace should also be provided with insulation.

Bonded ramming choice should be appropriate, some without bond, some only add a small amount of flux. Acidic castable material commonly used sodium silicate, ethyl silicate, silica gel bonded, the dry ramming material with borate; alkaline ramming material used magnesium chloride and sulfate; often use carbon containing higher at high temperature can be formed with organic carbon and temporary binder. The dry ramming material and fluxing agent amount of iron. Chrome ramming material used to mount pin.

Other unshaped refractory materials compared with similar material ramming material, a dry or semi dry loose,

rely on the strong ramming to obtain compact structure, only the heating to the sintering temperature, the combination will have the strength. Castable refractory after forming, according to the characteristics of mixed hardening, adopt different heating methods to promote the hardening or sintering.

Such as containing inorganic chemical bond, self hardening reached a considerable strength after baking mould; containing thermoplastic carbon mixture, after cooling has considerable strength and release, before use should be rapidly heated and coking; without bond hardening at room temperature, often with a model for sintering in the ramming.

Three common kinds of refractory castable

Refractory castable is monolithic refractories that widely produced and used currently. Mainly used for the construction of various heating furnace lining and so on overall structures. Some high quality varieties can also be used for smelting furnace.

Such as aluminates cement castable can be widely used for various heating furnace and other no residue, no corrosion of thermal equipment, and is the main varieties of refractory castable unshaped refractory materials, according to the different of the cementing material, curing and molding mechanism can be divided into three that hydraulic, air hardening and fire hard.

1. Hydraulic refractory castable: Using cement as the cementing material pouring in the hardening process require water to take part in a chemical reaction, forming a gel hardening strength, are hydraulic refractory castable. Cement is to determine the strength of castable (especially the atmospheric temperature strength) of the main factors, but its refractory degree is relatively low, so in that room temperature strength necessary, should as far as possible to reduce the amount of cement. If in order to compactness and construction workability, can be appropriate to increase the refractory powder. Reduce the amount of cement is also one of the measures to reduce the cost of. The construction should be strictly prevent aluminate cement and Portland cement, lime mixture. Because these two kinds of different chemical composition of the mixture will produce water aluminum acid calcium three, which greatly reduced strength.
   
2. Air hardening castable: Refers to the cementing agent in the maintenance of the absorption of CO2 in the air gradually solidified hardening. Refractory castable is the most commonly used water glass refractory concrete. Water glass refractory castable besides the performance of high-temperature resistance, it is acid resistant, abrasion performance, so often used as chemical equipment lining. Water glass, refractory castable process hardening under natural conditions is very slow, need to add coagulant in the construction (sodium fluorosilicate, high alumina cement).
3. Fire refractory castable: Using phosphoric acid and phosphate castable binder, need to pass through the heating and baking to obtain the strength and high temperature performance, so that the fire refractory castable.

Cannot insensible knowledge of refractory brick

Refractory brick can be referred to as fire brick, it has a certain shape and size, according to the different raw materials, refractory brick also has several different colors,

but most of them are the production of rectangular, and is in accordance with the different production process which can produce different kinds of brick. And refractory brick is divided into two kinds, one kind is the refractory materials and another is unshaped refractory material, since it is a refractory brick two different positive production process and the production of raw materials also each are not identical, refractories stereotypes are standard rules, can also be transformed according to the situation, and unshaped refractory materials is more regular production and become, have very strong liquidity.

Although there are several different refractory brick production and raw material but the results and effects are the same, it can withstand the high temperature combustion, also wear other than brick,

but of course its service life is long. But if you in the purchase of refractory brick, is to buy in the informal manufacturers then may buy refractory brick quality bad, not only short service life and refractoriness is not good, basic and common brick not what difference. Because the quality of the use of all those factory difference, low cost of refractory raw material for the production of refractory brick, the purpose is to use the low production costs to earn higher profits.

So people must not be cheated by them, only the regular factory will be good, reliable quality refractory raw materials to produce bricks can be used for a long time, refractoriness is strongest, but the regular factory and security, need not worry about customer service, these firebrick knowledge must remember.

Refractory industry will develop to green

In the development of our domestic industry, basically can achieve energy-saving environmental protection industry is not a lot, but refractory industry today we say it is belongs to the field of energy development.

In this industry, refractory materials, various types of products  , such as refractory brick, refractory castable etc. products, however, these two products are able to do energy-saving green development. Now with the major industry continue to emerge,  the state pay more attention to the refractory material production, and the development trend is apparent.

In fact, for the resources of our country market, we must also understand some of it, like oil, coal and other natural resources are declining, and the state is always in search for new products to replace the natural resources, but not too ideal. But in the domestic resources are becoming scarce today, appear energy-saving environmental protection refractory material model,

let this situation has improved, the state has approved the development of this industry. Because the development of this industry can promote the sustainable development of the country, and to other industry has brought a lot of use.

For the development of refractory products green, low carbon, our country has not given up, and to make great improvement, the development strategy in the global green economy, only the development of refractory industry of our country mainly, to comprehensive economic in China has greatly improved, and perhaps one day as a big refractory materials can also be the global market.

Difference between refractory brick and insulation brick

Effect of heat insulation brick is used to heat preservation, reduce heat loss, refractory brick is mainly used to withstand flame burn. Insulating brick is generally not direct contact with the flame, and refractory brick general direct contact with the flame.

The main difference between the following points:

• Insulation performance

Thermal conductivity of thermal insulation brick in general 0.2-0.4 (average temperature 350 ± 25 ℃) w/m.k, and refractory brick of heat conduction coefficient in 1 (the average temperature 350 ± 25 ℃) than w/m.k, which can obtain insulating brick insulation performance than the refractory brick insulation performance is much better.

• Refractoriness

Insulating brick refractoriness generally below 1400 degrees, and refractory refractory degree is above 1400 degrees.

• Density

Insulating brick is generally a lightweight thermal insulation material, density in 0.8-1.0g/cm3 and refractory brick of basic density is above 2.0g/cm3.

To make a long story short insulating brick is generally emphasized the insulation performance of it, does not pay attention to its refractoriness fire brick, and on the contrary. Different locations will use different materials, in the purchase of materials at the same time, to choose their own use.