Abstract:

Objective To identify the key hazard factors and risk positions in the wet acid dissolution purification process of precious metal recycling and refining enterprises through a semi-quantitative risk assessment model，and to provide data support and prevention and control strategies for occupational health management in the industry. Methods From 2024 to 2025，13 precious metal recycling and refining enterprises in Longgang District，Shenzhen City that adopted the wet acid dissolution purification process were taken as the research objects. Data and information were collected through on-site investigation of occupational health. Combined with the semi-quantitative risk assessment model of "Technical Guidelines for Occupational Health Risk Assessment of Chemical Hazardous Factors in the Workplace" and the risk assessment method of occupational accidents and occupational diseases in Romania，the hazard level，exposure level，risk index and overall risk index（Nr） were evaluated to determine the risk level. Results The main hazard factors in this process were classified into three risk levels. The high-risk factors（Nr=4） included carbon monoxide，nitric acid，and sulfuric acid，accounting for 18.75%. The medium-risk factors（Nr=3），comprising hydrochloric acid，sodium hydroxide，ammonia，and five other substances，accounted for 50.00%. The low-risk factors（Nr=2） included five specific factors，accounting for 31.25%. The distribution of job risks was characterized by the highest proportion of acid dissolution and reduction job risks，with the number of people in these positions accounting for more than 50%. The overall risk level of the industry was medium. Conclusion In this process，carbon monoxide，nitric acid and sulfuric acid are the key high-risk factors，and the acid dissolution and reduction positions are the key risk control positions. It is suggested that the overall risk level of the industry be reduced to a "low-risk" level through process optimization，intelligent monitoring and hierarchical control strategies.

Key words: Semi-quantitative, Risk assessment, Precious metal recovery and refining, Wet acid dissolution purification process, Hazardous factors, Occupational health