Recycle

Recycling flow

Recycling is an important issue from the all aspects as well as limited natural resources. Compared with plastics, metals are easy to recycle. Since limited kinds of magnesium alloys are used commercially, it is easy to collect  products made with same alloy series. Ingot magnesium can be reproduced with 4% energy required for the production from the raw material.
Fig.1 shows the typical flow for in-house recycling and recycling of painted parts.

Recycling method for Thixomolding™

Two kinds of recycling methods shown in Fig.2 can be considered.
The first method is called as remelting method. In this method, runner, sprues and defect parts are remelted, and refined to produce ingots.
The second method is direct crushing method. The process includes the mechanical grinding of such parts without remelting. Fine powders that are produced during the process are separated and can be used for chemical reactions.
Since the remelting process is excluded in the latter, it is cost effective.

 

The appearance of magnesium chip produced from both process are presented.
Although the shape of chips obtained from direct crushing method is somewhat irregular, it does not influence the molding process significantly, fabrication nature. Moreover, the impurity levels of both recycled materials are well met ASTM specification.

Remelting method
拡大
Remelting method
Direct crushing method<br/>
拡大
Direct crushing method

 

The mechanical property of the test specimen molded with by various recycled  chips is shown.
All samples exceed die-casting values, and even the keep the same level obtained with virgin material.

Production method of each sample

No

Alloys

Scrap origin.

Production method

1

AZ91D

-

Virgin

2

AZ91D

Die casting

Remelting

3

AZ91D

Thixomolding™

Remelting

4

AM60B

-

Virgin

5

AM60B

Thixomolding™

Direct crushing

6

AM60B

Die casting

Direct crushing

7

AM60B

Thixomolding™

Remelting

8

AM60B

Die casting

Remelting

9

AM50A

-

Virgin

10

AM50A

Thixomolding™

Direct crushing

11

AM50A

Thixomolding™

Mixture

Mixture=Virgin:Direct crushing(8:2)

Tensile strength of recycling magnesium alloys