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ObjectiveThree methods were applied to conduct occupational health risk assessment for the working positions exposed to silicon dusts in a sanitary ceramic manufacturing factory， and the evaluation results were compared to explore the applicability of different occupational health risk assessment methods.MethodsOne large sanitary ceramic product manufacturing enterprise in Songjiang District， Shanghai was selected to conduct occupational health risk assessment for the working positions exposed to silicon dusts， using occupational hazard risk index evaluation method， exposure ratio evaluation method， and International Council on Mining and Metals （ICMM） quantitative occupational health risk assessment method . The consistency of the evaluation results of the three methods was tested using weighted Kappa method.ResultsFourteen working positions exposed to silicon dusts were identified， and three positions had excessive dust concentration： composite forming position of phase 2 workshop （0.80 mg·m-3）， addition forming position of phase 2 workshop （1.00 mg·m-3）， and glazing position of 1F in phase 2 workshop （1.50 mg·m-3）， with an excessive rate of 21.42%. The occupational hazard risk index evaluation method assessed 6 positions with no harm， 6 positions with mild harm， and 2 positions with moderate harm. The ICMM quantitative occupational health risk assessment method assessed 6 positions with potential risks， 2 positions with tolerable risks， and 6 positions with intolerable risks. The exposure ratio evaluation method assessed 8 positions with medium risk， 5 positions with high risk， and 1 position with extremely high risk. The consistency test results of the three evaluation methods were poor. The Kappa coefficient between the occupational hazard risk index evaluation method and the ICMM quantitative occupational health risk assessment method was 0.15. The Kappa coefficient between the occupational hazard risk index evaluation method and the exposure ratio evaluation method was -0.09. The Kappa coefficient between the ICMM quantitative occupational health risk assessment method and the exposure ratio evaluation method was 0.04. The RR values obtained by the three evaluation methods were significantly correlated： the correlation coefficients between RRICMM quantitative assessment method and RRexposure ratio evaluation method， RROccupational hazard risk index evaluation method and RRICMM quantitative assessment method， RROccupational hazard risk index evaluation method and RRexposure ratio evaluation method were 0.915， 0.604， and 0.594， respectively. The correlation between the assessment result level and CTWA was strong.ConclusionThe occupational hazard risk index evaluation method is suitable for the working positions with low silicon dust exposure concentration， the ICMM quantitative occupational health risk assessment method and the exposure ratio evaluation method are suitable for the positions with high silicon dust exposure concentration， but all these three evaluation methods have limitations. It is more reasonable to use multiple methods at the same time in actual evaluation work.

Analytical methods of phosphoric acid, sulfuric acid and nitric acid in polishing solution, and methods of calibration of solvents by automatic potentiometric titrator were discussed. Nitric acid was titrated by ammonium ferrous sulfate, then phosphoric acid and sulfuric acid were titrated by sodium hydroxide, and the contents of three-acids were calculated. The results showed that the RSD value of ammonium ferrous sulfate calibrated by potentiometric titration was reduced from 1.1% to 0.13% and that of sodium hydroxide from 0.72% to 0.06% compared with traditional titration. The recovery rates of nitric acid in self-made samples and polishing products determined by potentiometric titration were 96% and 93% respectively. The recovery of phosphoric acid and sulfuric acid in self-made samples and polishing products by potentiometric titration was within 3%. The recovery of phosphoric acid and sulfuric acid by manual titration was 5%-10% deviation, and the recovery effect was inferior to that by potentiometric titration. By potentiometric titration, the recovery deviation of the three acidsin factory polishing liquid was less than 3%. The accuracy and precision of automatic potentiometric titration were much higher than that of manual titration. Automatic potentiometric titration makes up for the defect that manual titration could only analyze phosphoric acid and sulfuric acid, but can't determine nitric acid. [ABSTRACT FROM AUTHOR]