Hello and welcome, PeaceLoveLight!

You've come to the right place. We definitely understand the road you're walking and we have a lot of tools and experience we can share with you.
The sudden rages can be bewildering, can't they? Things are better for me now, but for a while, I never knew what might set my H off. Something as simple as my asking if he wanted to take the first shower in the morning could trigger three hours of ranting.

That's good that you're working on communication. It sounds like you've been in the habit of JADEing (Justify Argue Defend Explain). Perfectly natural. Most of us around here have done it at one time or another. But, as you've found, it's not only counter-productive, but sometimes actually harmful in a BPD relationship. Have you read much about
SET (Support Empathy Truth)? It's a much better communication tool.
Have you noticed any patterns to his rages? Are there things you know are triggers?
As for the silent treatment, it's a common thing around here. Usually, we advise people to go about their lives. Keep the door open to him. If you usually ask him what he feels like for dinner, ask. You may not get a response, but just do your best to shrug it off. Let him self-soothe and come back to baseline. In the meantime, focus on you. Do things you enjoy. Spend time with family and friends. Eat foods you like. Indulge in hobbies. Practice self-care. And learn as much as you can about BPD. We have a lot of helpful articles on this site.
And keep posting. We're here to listen and to help!