Mineralogical-based analysis of the toxicity reduction mechanism in haematitum processing

Haematitum is a mineral medicine with a wide range of clinical uses and has been in use for > 2000 years. It has a certain degree of toxicity, so it is usually processed by calcination and quenching methods to reduce its toxic side effects. It is important to clarify the processing mechanism for the further development of haematitum. Haematitum and processed haematitum (calcined and vinegar-quenched haematitum) were analyzed by scanning electron microscope, zeta potential analyzer, specific surface and porosity analyzer, X-ray photoelectron spectrometer, inductively coupled plasma mass spectrometer, and advanced mineral identification and characterization system. Moreover, evaluation of haematitum toxicity and procoagulant capacity using a mice model. The specific surface area of haematitum decreased from 17.04 to 1.42 m 2 /g and the zeta potential increased from −24.00 to −16.60 mV after processing. Processed haematitum and its major constituents (except quartz) are all larger in particle size than haematitum. The toxic heavy metal elements arsenic and lead in haematitum were reduced by 16.67% and 30.77% after processing, respectively. Some of the arsenic (III) elements are oxidized to the much less toxic arsenic (V) elements after processing. The iron (II) elements in haematitum are also partially oxidized to iron (III) elements. High doses of haematitum were toxic to the lungs, liver, and colon of mice, and the toxicity of processed haematitum was significantly reduced. Both before and after haematitum processing had procoagulant effects, and there was no significant difference. The mineral material properties of haematitum are altered by processing, such as surface properties, mineral composition, elemental composition, and elemental valence. These findings provide evidence that processing reduces the toxicity of haematitum without affecting the efficacy.