Melting method and recycling method for collected printing plates

Abstract

Since oxidation loss can be reduced even if collected printing plates are directly melted together with fresh ingots, a high melting yield approximately equal to a melting yield in the case of melting recycled ingots can be obtained. The present invention is a melting method for melting collected printing plates 35 and fresh ingots 37 by a burner 19 in a melting furnace 13, the collected printing plates 35 being collected used lithographic printing plates 36 and/or scraps 33 including offcuts of lithographic printing plates, the method including a first injection step of firstly injecting the collected printing plates 35 in the melting furnace 13 such that a pile of the collected printing plates 35 is formed on a hearth 13 B of the melting furnace 13, and a second injection step of injecting the fresh ingots 37 on the pile of the collected printing plates 35 so as not to substantially expose the pile, wherein the fresh ingots are melted in flames of the burner.

1 . A melting method for melting collected printing plates which melts collected printing plates and fresh ingots by a burner in a melting furnace, the collected printing plates which are collected used lithographic printing plates and/or scraps including offcuts of lithographic printing plates, the method comprising:
 a first injection step of firstly injecting the collected printing plates in the melting furnace to form a pile of the collected printing plates on a hearth of the melting furnace;   a second injection step of injecting the fresh ingots on the pile of the collected printing plates so as to cover the pile and not to expose, wherein; and   a melting step of melting the fresh ingots by exposing the fresh ingots to flames of the burner.   
     
     
         2 . The melting method for collected printing plates according to  claim 1 , wherein the melting furnace is a pre-rolling melting furnace of an aluminum rolling company. 
     
     
         3 . The melting method for collected printing plates according to  claim 1 , wherein an oxygen concentration in the melting furnace during the melting step is 11% or less. 
     
     
         4 . The melting method for collected printing plates according to  claim 3  wherein the oxygen concentration is 6% or less. 
     
     
         5 . The melting method for collected printing plates according to  claim 1 , wherein
 the melting furnace has an airtight structure having a chimney provided with a damper, and   smoke ventilation control is performed by opening and closing the damper so as to make an internal pressure in the melting furnace higher than an external pressure of the melting furnace.   
     
     
         6 . A recycling method for recycling collected printing plates which are collected used lithographic printing plates and/or scraps including offcuts of lithographic printing plates to reuse the collected printing plates as aluminum raw material for a support for a lithographic printing plate, wherein
 the collected printing plates are directly melted together with fresh ingots in a pre-rolling melting furnace of an aluminum rolling company without making the collected printing plates as a recycled ingot, and   the melting method according to  claim 1  is applied to the direct melting.