It's always hard to translate a complex sentence well in isolation i.e. without context. You need a unit after "3 billion" e.g. "units", "products" or is it money? If you are referring to a symposium in the past, you need to say "was achieved". "Contract volume" or "trade volume" are not standard collocations in ordinary English, in my experience, though I understand what you mean. However, they may be used in the relevant industry. Again, with some context, I might be able to come up with a more natural-sounding alternative.