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| Rapid Primary Screening Method for Water-soluble Chromium (Ⅵ) in Cement and Optimization Suggestions for GB 31893-2015 |
| Cheng Wei, Huang Wenjuan, Chen Zhiwen
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Guangdong Huizhou Institute of Quality and Metrology Supervision and Testing, Huizhou Guangdong 516003, China
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Abstract The current standard GB 31893-2015 "Limit and determination of the water-soluble chromium ( Ⅵ) content for cement" stipulates that the limit of water-soluble chromium ( Ⅵ) in cement is 10.0mg/kg. The determination method specified in the standard has problems such as cumbersome operation, timeconsuming procedures, high cost and large solid waste generation. In this paper, water dispersion - flame atomic absorption spectrophotometry was introduced for the rapid determination of water-soluble chromium ( Ⅵ) content in cement, and the effects of water-cement ratio (10∶1, 10∶2, 10∶4) and dispersion methods (glass rod stirring, ultrasonic dispersion) on the determination results were investigated respectively. The results showed that the optimal conditions were a water-cement ratio of 10∶1 combined with ultrasonic dispersion; the relative standard deviations of seven parallel tests were 0.42% and 0.56% respectively, and the deviations between the measured values and the standard values met the requirements of the repeatability limit and reproducibility limits of GB 31893-2015. The pretreatment time of this method is no more than 10 min, and it produces virtually no solid waste. It is suggested to adopt this method as the primary screening method and establish a determination system of "primary screening - reference method verification" (with a screening limit of 8mg/kg; samples exceeding the limit shall be retested by the diphenylcarbazide method), so as to provide a technical reference for the revision of GB 31893-2015.
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Received: 05 February 2026
Published: 25 September 2026
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