WO1985004907A1 - Preparation of charges comprising waste batches having a standardized average analysis obtained without fusion of said batches - Google Patents

Abstract

Process for obtaining moulded parts and billets in a standardized alloy without passing by the stage of ingots, characterized in that the productive foundry of parts utilizes directly in the furnace metal lumps and scrap of which the analysis is initially undefined, but which have been previously mixed with other metals in order to obtain a standard analysis. Process characterized in that it is particularly intended to the production of pressure moulded parts of aluminium alloy AS9U3 by starting directly from aluminium waste reduced into fragments by crushing.

Description

 Preparation of loads comprising batches of waste having a standardized average analysis obtained without merging said batches.

The object of the present invention is to do away with the melting and ingot stage to obtain molded parts and billets from pieces and scrap of metal.

Currently, in the metallurgy of 2nd fusion of metals, in particular aluminum, one leaves old molded parts called casings, boards, profiles and pieces and scrap of aluminum obtained after grinding.

These pieces and scrap of aluminum contain other metals, impurities and waste rock unsuitable for the manufacture of aluminum alloys which make a sorting essential which, after crushing, can be done manually, by density, ventilation, gravity, flotation, etc. The purpose of sorting is to eliminate the undesirable constituents in the manufacture of aluminum alloys, in particular zinc, zamack, copper, lead, stainless steel, magnesium, etc. non-metallic materials, plastic, earth, wood, rubber, etc.

The clean aluminum pieces thus obtained are melted in an oven. On the occasion of this merger, an analysis correction is made to bring it into compliance with standards and specifications. The liquid alloy thus obtained is poured into forms intended to make ingots. After cooling, the ingots are placed in piles and then delivered to different users: foundries, steelworks or laminators.

The invention consists, once the pieces and scrap of aluminum have been sorted, in exploiting a defined quantity of 1.5, 10 or 100 tonnes called "batch". By batch is meant a certain quantity of pieces and debris such that the size of the pieces allows homogenization by stirring, by mixing, etc. It will be necessary to carry out a new grinding if the size of the pieces is not in conformity. The batch consists of different alloys in unknown proportions.

Knowledge of the average batch analysis is obtained by melting a few kilograms of carefully removed pieces and debris. From this merger, we get a medal. The analysis of this medal will be representative of the analysis of the lot regardless of its weight.

The average analysis will make it possible to know the necessary corrections to be made to the batch for the compliance of the various constituents according to the average analysis.

Depending on the initial analysis, corrections can be made with richer or poorer pieces or granules of metal whose content is to be corrected. We can in particular use for the analysis correction other pieces and scrap of aluminum previously sorted whose average analysis is likely to modify the analysis of the batch in the desired direction.

It may be necessary to add copper, silicon, manganese, etc., to the batch in the form of pure metal or an alloy, which is preferable.

The addition of these analysis-modifying pieces will be intimately mixed with the batch using a drum for example.

The batch, the average analysis of which is thus made to comply with standards, will be delivered directly to consumers: foundries, steelworks or laminators to be placed as is in the ovens. These pieces and granules will be substituted for the ingots usually used in ovens.

The fusion of the different pieces will create the homogenization of the metal in the furnace of the producer of molded parts and billets.

The delivery of the batch can be done on pallets with cardboard, in bags, in containers or in bulk allowing the automated loading of the ovens.

The invention can be applied particularly to the production of die-cast parts made of aluminum alloy AS9U3.

Claims

1) Process for obtaining castings and billets in a standardized alloy without going through the ingot stage, characterized by the fact that the foundry producing parts uses directly in its furnace pieces and scrap of metals whose analysis, at initially, is undefined, but which have been previously mixed with other metals to obtain a standardized analysis.

2) Method according to claim 1 characterized in that waste having an average composition is used for the analysis of the batch without proceeding to the total fusion of the batch.

3) Method according to claims 1 and 2 characterized by the possibility of modifying the analysis of the batch by adding different metals or metalloids in pieces or granules which will be added to the batch and mixed very intimately. This will determine a new average analysis which can be further modified after analysis and so on until the desired average analysis is obtained.

4) Method according to claims 1,2 and 3 characterized by the direct loading, in the melting furnaces of factories producing molded parts and billets, pieces of debris giving after fusion an analysis in accordance with standards.

5) Method according to all of the preceding claims characterized in that it is particularly intended for the production of die-cast parts in aluminum alloy AS9U3 starting directly from aluminum waste reduced by grinding into fragments.