Effect of the Composition of Raw Materials on the Performance of Silica Ramming Mass Materials

What effect does the composition of raw materials have on the performance of silica ramming mass materials? A refractory material technology team studied the impact of the physical and mechanical properties of silica refractory ramming materials by adding clay and replacing silica with quartz sand. The results of the research experiment clarified the maximum addition amounts of clay from the Angren mine and quartz sand from the Jeroysko mine in the siliceous batching, thus determining the optimal batching composition of the silica ramming mass material. Experiments also show that in the ingredients of silica and clay mixtures, the amount of clay added should not exceed 25%. The amount of quartz sand used to replace silica in a mixture of silica, clay, and quartz sand should also be less than 25% and should be compatible with the amount of clay added. Based on the above experimental results, the formula of the best ingredients for the production of silica ramming mass materials was finally completed.

Silica Ramming Material – Acidic Ramming Mass

The above-mentioned experiments on the raw material composition of silica ramming mass materials also provide a realistic basis for the ingredients composition of amorphous refractory materials produced by various refractory material manufacturers using local raw materials. This is also one of the main problems that the refractory materials industry in many countries in the world urgently needs to solve.

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Will Silica Ramming Mass Materials Affect the Generation of Impurities During Copper Alloy Smelting?

“Accumulation of impurity elements” refers to the phenomenon that the content of individual impurity elements gradually increases after a certain alloy ingot (billet) has been continuously produced for a long time. The main reasons for the accumulation of impurity elements are as follows.

Absorbs impurities from silica ramming mass materials. During the smelting process, certain chemical reactions occur between certain elements in the high-temperature melt and the furnace lining. Moreover, when the reaction product can be absorbed by the melt, it will cause the content of corresponding impurity elements in the metal or alloy melt to increase.

The silica ramming mass material of induction electric furnaces is mostly composed of oxides such as silicon oxide, alumina, and magnesium oxide. Because the affinity of aluminum and magnesium for oxygen is greater than the affinity of silicon for oxygen. That is, both alumina and magnesia are more stable than silicon oxide, so high alumina sand and magnesia are used to make furnace linings. Silica ramming materials are not prone to chemical interactions with the melt; when silica sand is used to make furnace linings, the possibility of chemical interactions between the melt and the silica ramming mass materials is greater. The practice has shown that when aluminum bronze is smelted in a power frequency cored induction furnace with an acidic furnace lining, scrap products containing excessive silicon content sometimes reach more than 10% due to excessive melt temperature in the melting trench.

In order to prevent chemical interaction between the melt and the furnace lining, the melting temperature should be lowered as much as possible. Mainly, silicon ramming materials of different properties should be selected according to the different chemical properties of the metal or alloy being melted. Copper, brass, silicon bronze, tin bronze, etc. should be smelted in silica sand furnaces. Aluminum bronze and low-nickel white copper should be smelted in high-alumina furnace linings or magnesia furnace linings. Alloys with a higher melting ratio should be smelted in magnesia furnace linings.

When metals such as titanium and zirconium with strong chemical activity are smelted under vacuum, they can react with almost all silica ramming mass materials and absorb impurities. Only by replacing the refractory crucible with a water-cooled copper crucible can the problem of metal contamination in the furnace lining be solved.

When using sulfur-containing gas or heavy oil as fuel, during the heating and smelting process of copper and nickel, copper, nickel and sulfur react to increase sulfur. Even absorbing trace amounts of sulfur is very harmful. For example, nickel ingots containing more than 0.0012% sulfur will crack after hot rolling.

In addition, it is also obvious that the number of remelting increases with the copper smelted under the cover of rice bran and wheat bran. The phosphorus content also increases.

Therefore, silica ramming mass materials will affect the generation of impurities during copper alloy smelting.

High-Quality Alumina Magnesia Refractory Ramming Mass Material

The semi-wet refractory mixture constructed by the tamping method is called refractory ramming material. Unlike refractory plastics, this type of refractory mixture is a low-plastic or non-plastic tamping material. It is a compact body formed by forced tamping and then hardened by heating or roasting to obtain a certain structural strength. Rongsheng refractory materials manufacturer‘s tamping method construction material. In addition to plastic (wet ramming mix material) and ramming material (semi-wet refractory ramming material), there is also dry ramming mass material (non-liquid ramming material), which is a completely non-plastic ramming mass material.

Alumina-Magnesia Refractory Ramming Mass Material

Alumina-Magnesia Refractory Ramming Mass Material

The aluminum-magnesium ramming material is a semi-wet mixture that can be tamped and formed with aluminum oxide and magnesium oxide as the main components. It is made of high-alumina clinker (first-grade or super-grade bauxite clinker) or corundum as aggregate and powder, and water glass solution as a binder. The composition ratio of the ramming material is high-aluminum clinker (or corundum) aggregate and powder 88% to 92%, sintered or fused magnesia powder 8% to 12%, and water glass solution 7% to 10%.

In the composition of the ramming material, sintered or fused magnesia is added to the matrix in the form of fine powder. The purpose is that MgO and Al2O3 can react in situ to produce aluminum-magnesium spinel (Al2O3·MgO) during use. The formation of spinel can not only compensate for the sintering shrinkage of the ramming material but also improve the permeability and corrosion resistance of high-temperature molten slag.

The binder should be a high modulus water glass solution. Because the smaller the modulus, the higher the Na2O content, which will reduce the high-temperature slag resistance of the ramming material. Generally, a water glass solution with a modulus greater than 2.6 and a density of 1.2 to 1.3 g/cm3 is used as the binder.

General physical and chemical properties of aluminum-magnesium ramming material made with special-grade high-aluminum clinker and mid-grade sintered magnesia. The chemical composition is Al2O3 70%～75%, MgO 6%～10%. The bulk density after drying is 2.60 ~2.75 g/cm3. The compressive strength is 45～55 MPa. After firing at 1400°C for 3 h, the porosity is 22%-23%, the compressive strength is 70-85 MPa, and the linear change rate is -(2.0-0.8)%.

The aluminum-magnesium ramming material can be used as the overall ramming lining of the ladle, the lining of the induction furnace, and the lining of the tapping trough of the electric furnace. And high-temperature containers in contact with high-temperature metal solutions and solutions.

Refractory Ramming Mass Material for Steel Drums

The practice has proved that the aluminum-magnesium refractory ramming material that is used more frequently and has a better effect on steel drums, and its composition is also changed. When the amount of magnesia powder is 9%~12%, sufficient magnesia-aluminum spinel can be produced, which has good slag resistance and long service life.

The performance of aluminum-magnesium refractory ramming material is better. Its slag resistance is good, load softening temperature and high-temperature compressive strength is high, especially after 1400℃, the compressive strength reaches 105.9MPa. However, the line shrinks significantly after burning, reaching 2.21%. The material can generate aluminum-magnesium spinel at high temperature, which grows staggered, expands in volume, and is a refractory mineral, so its performance can be improved.

The fire-resistant ramming material is thrown on-site and rammed with a pneumatic pick or machine, and the wind pressure is not less than 0.5MPa. The parts with less material or not important to use can also be knotted manually. Therefore, the inner lining of refractory ramming material has low moisture content and dense knots, and its performance is better than refractory castables of the same material. The disadvantage of refractory ramming material is slow construction speed and high labor intensity. There is a tendency to be replaced by dry vibrating materials and high-quality refractory castables.