Funny you mention the “virgin lead”. When I was just out of school, I worked at a battery plant in PA. It made communication batteries Designed by Bell Labs. These were giant 300 lb. round batteries. They were very high tech lead/acid and expensive. The batteries they replaced had a 1 year warrantee and typically lasted 5. These high tech ones had a 5 year warranted and lasted 30. The were two things that made them special. The round shape had about 6” of space at the top to expand without busting the case and they uses 99% pure lead. They we’re about 14” in diameter and 30” tall. They were only 2 volts, but you could melt a wrench if you dropped it on the terminals.
When the Optima batteries came out, I wondered if they shared some of the tech. (like the extra room to expand) I don’t know if “virgin lead” means pure lead. At the time it was explained to me that all batteries used antimony lead. (Whatever that is”