Method of and apparatus for the production of nodular (ductile) cast iron

An in-ladle process of treating a molten cast iron base metal with a magnesium based nodularizing agent, the ladle having a main chamber, a reaction chamber adjacent the bottom of said main chamber, a charging and filling passage leading downwardly from the top of the ladle to said reaction chamber, and one or more passages leading from said reaction chamber into said main chamber, said process comprising of the steps of:

• placing a predetermined quantity of nodularizing agent in said reaction chamber;
• rapidly filling said main chamber with a desired quantity of molten iron via said charging and filling passage, via said reaction chamber, and via said reaction chamber/main chamber passages;
• establishing a level of said molten base metal above said nodularizing agent within said reaction chamber of sufficient depth to substantially contain the reaction between said magnesium nodularizing agent and said molten base metal so as to inhibit the escape of excess magnesium oxide to the atmosphere and so as to maximize the recovery of magnesium within the molten base metal;
• and
• holding said molten base metal in said main chamber for a time sufficient to complete the mixing of said magnesium and said base metal.

An in-ladle process of treating molten iron base metal which, but for the treatment of said process, would be grey iron upon solidification, said process being carried out in a ladle havin a main chamber, a reaction chamber separate from and interconnected to the bottom portion of said main chamber, and a charging passage separate from said main chamber in communication from above with said reaction chamber, said process comprising of the steps of:

• a placing a charge a nodularizing agent in said reaction chamber, said nodularizing agent containing a reactive substance ranging between 1 and 10% by weight of said nodularizing agent, said reactive substance being selected from magnesium, cerium, lanthanum, calcium, potassium, lithium, sodium, beryllium or yttrium;
• pouring said molten base iron into said main chamber via said charging passage and said reaction chamber wherein said molten metal reacts with said reactive substance as said molten metal flows through said reaction chamber into said main chamber;
• and
• inducing a reaction between said molten base metal and said reactive agent as said base metal flows through said reaction chamber into said main chamber wherein between 65% and 99% of said reaction agent in the nodularizing agent placed in said reaction chamber is recovered by said molten metal poured from said main chamber.

An in-ladle process of treating a molten cast iron base metal with a magnesium based nodularizing agent, the ladle having a main chamber, a reaction chamber adjacent the bottom of said main chamber, a charging and filling passage leading downwardly from the top of the ladle to said reaction chamber, one or more discharge passages leading from the bottom of said reaction chamber into said main chamber, and one or more other discharge passages leading from said reaction chamber at a level above said bottom discharge passages to said main chamber, said process comprising of the steps of:

• placing a predetermined quantity of nodularizing agent in said reaction chamber;
• introducing molten iron into said reaction chamber via said charging and filling passage at a rate greater than said molten metal may be discharged from said reaction chamber into said main chamber via said discharge passages at the bottom of the reaction chamber;
• establishing a level of said molten iron within said reaction chamber of sufficient depth to substantially contain the reaction between said nodularizing agent and said molten iron so as to dissolve said nodularizing agent into said iron, so as to inhibit the escape of said nodularizing agent to the atmosphere, and so as to maximize the recovery of said nodularizing agent within the molten iron;
• after filling of said reaction chamber with molten iron to the level of said other discharge openings, discharging molten iron into said main chamber from all of said discharge openings at a rate greater than or equal to the rate at which said molten iron may be introduced into said reaction chamber via said charging and filling passage;
• and
• holding said molten iron in said main chamber for a time sufficient to complete the mixing of said magnesium and said base metal.