Simple Solutions That Work! Issue 12

14 However, it can still give rise to the opportunity for the ladle to be overfilled. So, I would always recommend that the metal is weighed into the ladle. The ladle design should have a safety factor such that that this additional weight will not compromise the ladle but it’s not good practice if you have charged the ladle with additives for 1000 Kg (2200 lb) of metal and then fill the ladle with 1100 Kg (2420 lb) this could push the crane to its capacity. B efore I move onto the tun-dish ladles, I’d also like to mention wire feed treatment ladles. I’ve found that what makes a good deep treatment ladle is usually applicable to the wire feed ladle design. With wire feed ladles, the constraints are defined by the wire feed machine so the ladle has to be designed to suit this. If the open top deep treatment ladle is the easiest to live with then the loose and sliding tun- dish are the next easiest. The Tun-dish cover being clear of the ladle after the treatment process has been completed. Access to inside the fixed and teapot spout ladles is extremely limited so these ladles work best when the treatment cycle is constant with the through put of metal washing out any build up inside of the ladle. The downside being that the scale works in the other direction when it comes to Mg recovery, with the fixed tun-dish and teapot spout ladles giving much better results and the open top treatment ladle the least. TUN-DISH LADLES All tun-dish types of ladles have a shared principle that the molten metal enters the ladle through a restricted opening and the metal seals the ladle so that when the reaction takes place no more air can get into the ladle. These ladles don’t usually have additives pocket in the base of the ladle; instead they have a divider (a weir) in the base of the ladle to form a reaction chamber. LOOSE TUN-DISH The loose tun-dish is basically an open top treatment ladle with a tun-dish. The cover is removed by an independent method (hand, forklift truck or crane) after the treatment cycle has finished but before the ladle is rotated. The additives are placed in the ladle with the tun-dish removed. Sometimes a sandwich layer is placed over the additives and the tun-dish is then placed on the ladle and the ladle filled via the tun-dish. When the reaction has stopped the tun-dish cover is simply removed. The ladle treatment process can be completed and the metal de-slagged before, usually, being poured into casting ladles. With the covered ladles effectively being sealed, the Mg fume is also greatly reduced.