Although this article started with a general overview of the iron and steel industry, we will refer only to one process for the portible rest of this feature, a gray iron foundry using an electric arc furnace. We will see how important brick and refractory are and why everyone should pay attention to their brick and refractory designs and installations.History and Background of the Electric Arc FurnaceThe electric arc furnace (EAF) has been around since the early auto 1900s and is primarily used to produce high quality alloy steels. EAFs have refractory-lined steel shells and vary ill size from only a few feet in diameter to twenty feet or more. The bottom, or hearth, of the furnace is dished to hold the metal charge. The vertical side walls include one or more doors and a tapping spout for removing the melted charge. The roof over the furnace is dome-shaped, and incorporates two or three openings near its center for the admission of electrodes into the furnace. The roof is usually detachable and is lifted off or turned aside for charging. The whole furnace structure is tilted forward and backward for slag skimming or tapping. The furnace capacity will depend upon the size of the furnace and can be less then one ton per charge to up to eighty-five tons per charge.

Type heaters of Mortar--The mortar should match closely with the type of brick being laid. Using the proper mortar will help eliminate expansion differences between it and the brick. If the brick inside a ladle is laid with too thick of a mortar joint, and the mortar does not match closely with the chemical characteristics of the brick, gaps or cracks will result when the ladle is preheated to 1500[degrees]F.Many have asked about the strength of the mortar versus that of brick or tile. Mortar is definitely stronger. A crack will almost always form in the brick itself before it begins in the mortar. Anyone that has tried to reuse brick after a demolition of an existing brick structure knows how difficult it is to separate the brick and mortar from each other. The bricks usually break or crack and, for the most part, cannot be re-used. That is why a thin coating of mortar is better than a thick coat and why dipping is specified in application of mortar to brick.

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