Method for the preparation of magnetically traceable explosives

摘要

The invention provides a novel magnetically traceable or detectable explosive blended with a magnetic ferrite powder which facilitates the detection of the misfired explosive, e.g. dynamite, remaining in the field after blasting by a magnetic means but not to adversely affect the stability of the explosive. The ferrite powder is freed of any free alkalinity on the surface before blending with the explosive either by washing with water, neutralization with a dilute acid, reaction with an acid followed by washing with water or neutralization with an alkali and/or by coating with a polymeric material on the particles. The most efficient method for the coating of the ferrite powder with a polymeric material is the in situ polymerization of a radical-polymerizable monomer in contact with the ferrite particles in the presence of hydrogensulfite ions and the explosives blended with such a polymer-coated ferrite powder retain their stability even after a prolonged storage.