Calderys

Alkali Corrosion

Calderys Solutions

 

In many cement plants, petrochemical and boiler units, and incinerators, damages from alkali corrosion can be a significant factor of refractory wear. Refractory material can react with soda (Na2O) and potash (K2O) to form alkali alumino-silicates. Alkalis K2O and Na2O are in volatile form as sulfates and chlorides. When they penetrate the refractories, alkalis react with the matrix and aggregates to form, with alumina and silica, new phases with growth-expansion and very low melting points, which leads to severe spalling and destruction of the lining.

Poor alkali resistant castable
Poor alkali resistant castable
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Good alkali resistant castable
Good alkali resistant castable
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Matrix permeability limits the corrosion

When enriched with the additives silicon carbide (SiC) and zircon silicate (ZrSiO4), Low Cement Castables (LCC) and Ultra Low Cement Castables (ULCC) demonstrate a lower permeability and improved resistance towards alkali corrosion. Calderys offers a full range of these products to combat the most severe conditions. Calderys has also developed a specific range of products without additives, but with a matrix alkali resistant.

Conventional castable matrix
Conventional castable matrix
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Low Cement matrix
Low Cement matrix
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Ultra Low Cement matrix
Ultra Low Cement matrix
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Products that decrease or limit the corrosion

Silicon Carbide compounds are an effective solution. At operating temperature, decomposition and oxidation form specific glass phases—blocking the porosity and forming new phases with the alkalis without disruptive growth. There is little to no spalling of the hot face and alkali penetration is reduced. For incinerators and boilers, silicon carbide based ramming mixes and patches, respectively in our CALDE™ RAM and CALDE™ PATCH ranges, present very good resistance to alkali corrosion. The alkalis may penetrate the surface, but they will not develop new expanding compounds

Zirconium compounds are another effective solution. They react with alkalis at operating temperatures and form a glassy phase protecting the lining. Certain combinations of the above systems give exceptional resistance for severe cases. Again, the alkalis may penetrate, but they cannot develop new expanding compounds.

Certain combinations of the above systems give exceptional resistance for severe cases. Calderys has developed custom solutions for plasma torch furnaces, rotary kilns, hospital incinerators, and other units operating at very high temperatures which are subject to corrosion by molten ash.

You need a dedicated Alkali Resistance solution, contact our experts!

About Calderys

Our mission is to help you meet your ever increasing production and productivity targets, whilst protecting the safety of your people and the integrity of your equipment. Our focus is to deliver safe, reliable and high performing refractory solutions customized to your needs. Our international production and sales facilities allow us to develop and deliver customized solutions based on monolithic and ready shape monolithic refractory materials worldwide in a fast, efficient, and safe manner.

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