preserving foods

In the process of home preserving food there is a packet of something that is added to dry ingredients that removes oxygen from jars,bags etc. Its used to keep dry beans,peas,flour etc from spoiling when it is desired to keep them for long poriods of time.
What is that material?
Where can I purchase it?
Can I make it myself? How?

The material is silica gel.

I believe silica gel removes moisture.
I want to remove oxygen.

You’re not talking about a vacuum device that pumps the air out? If you aren’t, then I have no idea what you are referring to.

Like this one:

Not a vacuum device.
From what I understand the Mormons use an oxygen removing,maybe absorbing or maybe it outgasses an inert gas to drive the oxygen out, packet in their food packaging. Apparently they have their own canning companies.
I have been advised to get the packets from them but I don’t know where are any of these places.

Oxygen Absorbers for food products
Some oxygen absorbing packets are made with finely powdered iron. This will rust and remove the oxygen from a closed container. Ascorbic acid, organic dyes, and enzymes are also used in food-grade oxygen removal systems.