CALDERYS INDIA EXPERTISE IN ALUMINIUM
Calderys India has decades of experience in serving Aluminium industry. We have been working for years with worldwide engineering companies, Process licensors, contractors and end users in the Aluminium industry. We have experience of catering to requirements of integrated aluminium producers and aluminium foundry. This experience has made us customer’s preferred choice for new projects as well as for ongoing plants. Our proposals have helped our customers to improve Refractory life, productivity and safety.
Our product range is comprehensive for an integrated aluminium producer as well as well as for foundries. This covers monolithics and shaped products. Our innovative product range like Accmons, AC-85P have been creating performance bench marks since decades.
Our experts do regular interactions with Aluminium industry and have developed good understanding on Al making process. This understanding coupled with refractory knowledge and experience helps us to arrive at most workable product and solutions.
Subsequent to merger with Calderys, we have access to their product range and expertise. Calderys is a world leader in refractory solutions for aluminium industry. They have over 60 years of successful experience in aluminium industry worldwide. With this support, Calderys India is able to bring in global Refractory expertise to Indian Aluminium industry along with local knowledge.
We have capability to design refractory lining for Aluminium furnaces. Our design solutions provides better energy efficiency, reduced maintenance downtime, and longer repair cycles, thereby improving profitability. Our products and solutions extend following advantages:
- Non wettability of Refractory lining improve upon longevity of Refractories.
- Suppress corundum build-up
- Withstand mechanical abuse thus increase service life.
- Ensure the safety, reliability, and productivity of the equipment
Our understanding of the corundum formation with new modern alloys containing magnesium, zinc and other elements like strontium has led to the development of specific dense castables. They are not wetted and not impregnated by these alloys, thanks to special additives added to LC or ULC castables which present low porosity and high mechanical strength to avoid the mechanical abuse during charging and cleaning.
The major stresses to the lining in Al furnaces with Al contact are
- Corundum formation by oxidation and/or corrosion
- Mechanical abuse.
Corundum formation by oxidation
At the surface of the bath, molten Al oxides with oxygen in the atmosphere:
4/3 Al2 + O2 2/3 Al2O3
Liquid aluminium and its alloys react with the refractories to form corundum by reduction of silica.
4 Al + 3SiO2 2Al2O3+ 3Si
This corundum is very hard to remove and its growth decreases the capacity of the furnace, up to its stoppage in the worst case. Aluminium reduces the silica of the refractories as well as all other reducible oxides with the formation of internal and external corundum. Internal corundum grows and destroys the lining. External corundum decreases the capacity of the furnace up to its complete stoppage. The modern aluminium alloys contain magnesium, zinc, copper and other element such as strontium. Theses additions accelerate the corrosion of refractories with corundum growth. (For example unstable alumina-magnesia spinel).
Before each casting the bath surface needs to be cleaned and dedrossed (to avoid pollution of the metal), and it is also necessary to mechanically clean the furnace periodically. It suffers from the impact during charging. This bottom as well as the sidewalls and the ramps can be damaged during cleaning and dedrossing.
We have significantly improved the low cement technology, compared to conventional castables, and patented it: very high mechanical strength in a wide range of temperatures and low porosity to reduce the infiltration of liquid metal. LC castables have been used to line aluminium furnaces. With the arrival of new alloys, our research wing has developed a new range of low cement castables with additives which prevent the wetting and the impregnation by aluminium and its alloys and suppress quite completely the corrosion stresses. As the corrosion starts in the matrix, our newly developed castables have a silica-free matrix. Theses castables are installed by casting, vibrating, pumping of self flowing products and also by gunning of LC castables. For reasons of ease of installation and low initial cost, we have kept phosphate bonded high quality fire bricks and insulating bricks in our range of solution. A combination lining of bricks and castables can be worked out to optimize overall operational cost.
Equipment in the Primary Aluminium industry such as the anode baking furnace, alumina calcining rotary kiln and flash calciner, electrolysis cells, and foundry are all well known to Calderys India. Furnaces and equipment featuring refractory lining that come into contact with liquid aluminium suffer from severe corrosion by corundum formation, which leads to build-up, and form mechanical abuse. Unit commonly affected by this severe corrosion are:
- Tank melting and holding furnaces
- Recycling furnaces
- Barrel melting furnaces
- Single chamber shaft melting furnaces
- Bi-chamber shaft melting furnaces
- Dosing furnaces
With extensive knowledge of the aluminum-making process, our experienced supervisors and installers can offer specialized technical support. Calderys India provides expert technical guidance and the best suited installation equipment to ensure the refractory performance during service.
This can be applied to small, large, or turnkey projects alike depending on the customer requirements. Alternatively, we can support the customer's staff by supervision, project management, equipment, and also direct installation training. Our aim is to ensure the best installation and dry-out of the refractory lining to achieve maximum performance.
Once in service, the refractory may require specific maintenance which can be furnished depending on the equipment. With its range of LC and ULC castables, Calderys India has developed products for repairs by gunning, casting, and patching. In some cases, and depending on the situation, services may be available 24 hours per day, 7 days per week, ensuring minimum downtime for the customer—especially for unplanned emergencies
Our engineering teams, dedicated to the Aluminium industry, help customers to meet a wide range of needs. Starting with the shell design, we design a full lining with heat transfer calculations, show the intermediate and casing temperature, and define the thickness of the different layers:
The Calderys India solution for the bath is a lining of Low Cement (Aluminium contact) castables, insulating castable (with non-wetting agent to prevent damage in case of accidental infiltration), then insulating boards.
Hot face dense castable featuring the following: good thermal shock resistance and alkali resistance, insulating layers, anchoring with anchor-bricks or metallic anchors, expansion joints. Burner blocks with ramming mixes to allow burner start-up at mid-drying schedule (carried out with external hot air generators).
Suspended with ceramic anchors, hot face with dense castable featuring good thermal shock resistance and insulating layers to ensure low external temperature under the metallic supporting beams.
Calderys India provides engineering drawings, bill of materials, project quotation, planning, installation and dry-out.
Calderys India is often consulted in the development of technical solutions covering precise specifications. Familiar with the processes of each customer, we are able to engineer a refractory solution, provide project management services, and advise on the proper installation techniques for new projects. Calderys India has an excellent reputation for providing reliable solutions which have created many long-lasting relationships with our customers. Our strategic partnership with the customers ensures that we develop market-oriented solutions. With our more than 20 years of experience in the Aluminium industry, Calderys India has the capability to become an integrated refractory partner and can meet all the needs from solution design to implementation.
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