NEW ANODE RODDING SHOP SOLUTIONS

NEW ANODE RODDING SHOP SOLUTIONS

1970, Eastalco, State of Maryland, USA: ECL commissioned his first complete anode rodding shop, from loading/unloading station to casting station. 40 years later, ECL has gained an extensive know-how and unrivalled experience with more than 40 smelters equipped with ECL machines across 6 continents. Able to offer from single machines to turnkey rodding shops for all types of anode (2, 3, 4 or 6 tubs) including engineering of the building (Alba Line 5 – 2003, Jonquière – 2009, Balco – 2010) and construction of the building (Emal Phase 1, 2010); ECL has designed and set up more than 280 machines, constituting the largest worldwide installed base in the primary aluminium industry.

Rodding shop design through flow management Needless to say that the anode rodding shop is a complex system playing a major role

in the smelter efficiency and productivity. Its performance can dramatically influence reduction line operation but also the lifetime of Anode Baking Furnaces flue walls. The reduction line must be constantly supplied with new anodes whereas spent anodes are taken out of the pots. Hence the rodding shop has some absolute imperatives: quality, productivity and reliability. It’s why ECL attaches considerable importance to the first phase of the rodding shop: DESIGN. As a start, ECL always considers first the smelter’s targets in terms of production quality and productivity. This includes identifying solutions to reduce operating cost and increase capacity. The type and quantity of stations needed is only a part of the equation. To help it in this task, ECL employs a highly specialized software (Witness®) commonly used in the automotive industry to organize and simulate the anode

flow, taking into account the cycle times, reliability and availability rates of machines, anode buffer sizes between machines, conveyors speed and machines locations.

Various solutions are simulated to determine the best set of machines and rodding shop organization.

This allows ECL to guarantee an efficient solution with given production performance for single machines or complete shops.

To ensure the optimum productivity of the shop, a global flow, production and maintenance management system can also be put in place. To this end ECL provides a level 2 solution giving access to a large amount of information regarding each station and the whole rodding shop operation. The centralized computer receives from each station several information such as Input, Output, Alarms status, fault status and operator’s shifts changes. The computer

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Butt entry

Stem Exit

Carbon rejection

analysis helps determine for each machine the availability rate, the breakdown statistics and therefore its reliability and productivity. The level 2 solution allows the total optimisation of the rodding shop.

It can also assist in determining which station needs to be doubled or replaced for a possible smelter expansion. As a reference, at Alba smelter only 9 shifts per week have been determined as necessary to produce the anode assemblies required for the 336 pots (AP35 technology) whereas 12 shifts were specified originally.

When designing rodding shop equipment, ECL also focuses on environment, health and safety.

Special features, unique technical solutions and extensive safety systems have been designed to control the dust created by the spent anodes cleaning process and the high noise levels in order to help our customers in their HSE efforts and ensure a safe and clean working environment for the workers.

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Cast iron thimbles rejection Innovation, around specific customer requirement ECL is constantly investing for the future, continuously innovating and continually partnering with its customers for win-win solutions no matter is the project: complete turnkey system for Greenfield smelters or retrofit project within an existing plant. ECL delivers improvements in operational efficiency while always adding value to its customer’s assets.

For instance, we can underline the high level of ECL innovation with the 2-in-1 station. Even if each station is assigned to a specific task in the cleaning or rodding process, ECL designated and commissioned in 2009 during EMAL‘s phase 1 the Butt & Thimble Stripping Machine. It combines the butt stripping and thimble breaking functions which brings remarkable savings in capital investments but also significant reduction of the total cycle time. Special jaws are placed around the anode stubs, protecting them from bending.

They are equipped with knives on

PRIMARY SMELTING AND PROCESSES

the underside that break the carbon block when it is pushed against them by the breaking tool coming from below. Once the carbon is removed, the same tool continues its upward movement to push the thimbles against the lower surface of the jaws, until the bottom of the anode stub reaches the level of the jaw. Both carbon and iron pieces fall on the same conveyor. They are separated for recycling by pushers on a sorting table. The total cycle time is lowered down to less than 50 seconds per anode, against 88 seconds for separate stations.

We can also mention the anode cooling tunnel, one of the last but not least functional machines developed by ECL engineers and recently installed at Emal as well.

This system ensures the heat treatment of spent anodes after the hot bath removal facility. The cooling tunnel use blowers to force ambient air or outside air into the tunnel while drawing heated air from the anodes out after filtering.

These results in significantly faster cooling times: the air volume blown in tunnel is calculated to lower down anode’s temperature of 200°C (392° Fahrenheit) in an hour, against 80 hours without cooling system whereas the butt conveyor length is reduced by 15% compared to a natural cooling solution.

By manufacturing and commissioning 28 complete anode rodding shops, ECL has been able to constantly optimize the design of each station, increase dramatically the reliability and to create some innovative new ones to meet with customer’s requirements.

ECL is committed to reach the performance required to feed smoothly the potrooms with sealed anodes of the highest quality, in the safest and most reliable environment as well as the lowest operation costs.