美国采购需求：cas：39409-82-0，碳酸镁，食品级超轻质碳酸镁，轻质碳酸镁，碳酸镁粉，食品添加剂

I'm in the process of launching a climbing chalk brand in the U.S. and am on the lookout for a dependable supplier of high-purity magnesium carbonate. Could you share your pricing per pound for different bulk orders, such as 25 lb, 50 lb, and 100+ lb? It would also be great if you could let me know your minimum order quantities and any relevant certifications you have. Additionally, I'm interested in the lead times and shipping options within the U.S., specifically to California. Since safety and quality are top priorities for my brand, any documentation or safety data related to your products would be very helpful. Looking forward to your detailed response!