Melting Yield in Printing Plate Recycling
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Solution Overview
Problem
Direct melting of collected printing plates in a pre-rolling melting furnace results in energy inefficiency and significant oxidative loss due to their large surface area, leading to a lower melting yield compared to recycled ingots.
Innovation Solution
The method involves injecting collected printing plates into a melting furnace to form a pile, covering them with fresh ingots to prevent exposure to flames, and melting the ingots first to create a protective molten metal layer for indirect heating, while controlling oxygen concentration through air-fuel ratio and smoke ventilation to minimize oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If collected printing plates are directly melted in a pre-rolling melting furnace, then energy efficiency is improved by eliminating the intermediate recycled ingot production step, but oxidative loss increases due to the large surface area of thin-plate printing plates
Solution Approach 1:
Fresh ingots serve as an intermediary protective layer between the collected printing plates and the oxidizing atmosphere. The fresh ingots are placed on top of the printing plates before melting, creating a physical barrier that prevents direct contact between oxygen and the printing plate surfaces, thereby reducing oxidative loss while maintaining energy efficiency
Solution Approach 2:
The melting process creates a reducing atmosphere through controlled combustion conditions where the flame zone establishes an oxygen-deficient environment. By controlling the air-fuel ratio and positioning the burner appropriately, the atmosphere around the printing plates becomes protective against oxidation, allowing direct melting without significant oxidative loss
2Device complexity
If collected printing plates are directly melted without forming a protective layer, then the melting process is simplified and energy consumption is reduced, but melting yield decreases due to combustion and oxidative loss
Solution Approach 1:
Fresh ingots are placed on top of the collected printing plates before the melting process begins. This preliminary arrangement creates a protective configuration that will maintain itself during melting, ensuring high melting yield without requiring complex protective equipment or multi-step processes
Solution Approach 2:
The fresh ingots automatically serve their dual function: they are both the material to be processed and the protective barrier for the printing plates. As the fresh ingots melt, they continuously provide protection to the underlying printing plates, eliminating the need for separate protective measures while maintaining high melting yield
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances melting yield to levels comparable to recycled ingots, reducing energy consumption and oxidative loss, thereby improving energy efficiency in recycling collected printing plates into aluminum raw materials for lithographic printing plates.
Implementation Method 1
melting the ingots by exposing to flames of the burner
Implementation Method 2
melting the ingots by exposing to flames of the burner
Implementation Method 3
The collected printing plates are melted in a state where the collected printing plates are soaked (immersed) in molten metal of the fresh ingots
Implementation Method 4
a first injection step of firstly injecting the collected printing plates in the melting furnace
Data Source
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AI summary
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 13B 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.