Simple Solutions That Work! Issue 13

12 send the ladle away to a specialist company to have this done, then you can be adding days or even weeks to the ladle turnaround time. Therefore, one of the refractory developments that is most interesting is the pre-cast liner, also known as drop-in liner or monoform pot, for iron and steel ladles. Several refractory companies have developed and are expanding this concept. As a ladle manufacturer, we have to be aware of these advances and see if the ladle designs need to adapt. The process is similar in principle to the Foseco insural liners, but is for use with molten iron and steel. Typically, a base of lining powder is placed in the ladle and then the monoform pot is placed into the ladle shell and centrally positioned. The space between the pot and the ladle shell is back-filled with lining powder, which is vibrated down to compact it. This lining powder acts as a safety lining and also often allows the use of ladles that are not specifically designed for the monoform pot to be used. The top of the ladle is capped off with a refractory layer to seal it and stop the powder from falling out when the ladle is tilted. Typically the ladle will have either a detachable steel flat ring or plates to hold the pot in place when the ladle is rotated. It is better to design the ladle from the outset to be used with a monoform pot, but you don’t have to always get a new ladle if you are thinking of using them. This monoform pot should last as long as a castable refractory (it’s basically the same material). To replace, it is a simple case of removing the ring or plates and then inverting the ladle. A few blows on the base of the ladle are usually enough to have the pot and the powder drop out, with the pot in one piece. The ladle can then be cleaned out and relined with a new pot in a matter of hours. This process is far more efficient and reduces replacement time to 4-8 hours depending on the ladle size and type. Compared to 24-36 hours if completed in house, or 2-3 weeks if the ladle was previously shipped out to a specialist refractory company. This quick turnaround of ladles can greatly assist a foundry’s production by removing a potential bottleneck if they have a limited number of ladles available. Use of the monoform pots can also reduce the risk of white vibration finger for the operative who has to wreck out the old lining. A few taps to the base of the ladle is far better than several hours with a jack hammer or pneumatic chisel. From the ladle design point of view, the use of the pre-cast pots presents a number of possibilities. It is easier to adapt the ladle shell to suit an available pot size. And, when it comes to treatment ladles, teapot spouts, or odd shaped ladles, using a pre-cast liner can greatly simplify matters. Both when it comes to fabricating the ladle and when installing/replacing the lining. FOR EXAMPLE: We’ve been supplying teapot spout treatment ladles to EJ since 2003. Initially these ladles were supplied with a multi-piece lining former and the lining of these ladles was a major undertaking. We were made aware around 2013-14 that EJ had adapted these ladles for use with a monoform pot liner. We supplied an additional teapot spout treatment ladle to EJ in 2016 and this incorporated a number Contact: STEVEN HARKER steven.harker@acetarc.co.uk of changes to make it easier to use with the monoform liner. For the new EJ Elmira facility, we worked closely with EJ to design the ladles to match their very specific requirements and the ladles were effectively designed around the monoform liner that they intended to use. The experience that EJ Ardmore had gained with the use of the pre-cast liners, clearly made them the choice for their new facility. The EJ Elmira ladle shape was complex, with two extended spouts and the use of a pre-cast monoform liner, greatly simplified the lining of the ladles. I’d like to leave the last word to Brian Gorton of Weir Minerals. When asked about the advantages of the drop-in liners, he provided this feedback: • Less impact work on the operator - removal of exposure to vibration from lining cleaning and knock out (HAVs). • Safer working environment- Reduced exposure to dust, noise and working in confined spaces. • Improved control of ladle lining and maintenance costs. • Increased availability of ladles for production planning. • Production is no longer affected by a lack of ladles available. • No damage to ladle shell after being knocked out by a mechanical method. • No repair costs. • No need to strip casting mechanisms off and replace them once the ladle is returned. • Quick turn around on knockouts and relines.