▎ 摘　　要

NOVELTY - A composite purifying additive comprises 30-40 pts. wt. heavy calcium carbonate, 5-9 pts. wt. calcium borate, 3-5 pts. wt. nickel oxide, 1-3 pts. wt. tungsten carbide, 2 pts. wt. graphene, 8-12 pts. wt. bulking agent and 30-40 pts. wt. carrier. USE - Composite purifying additive is used in direct mercury detector for detecting sample e.g. high-sulfur mineral and coal (all claimed). ADVANTAGE - The composite purifying additive with high purification efficiency is prepared by simple and economical method. The direct mercury detector using the composite purifying additive has excellent durability, extended detector tube life, reduced soot pollution and cost of detector maintenance, excellent protection of internal components, and improved detection characteristics, mercury recovery rate and detection accuracy. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for usage of composite purifying additive in direct mercury detector.