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| Countermeasures for High Content of Water-soluble Hexavalent Chromium in Cement Clinker |
| Tianrui Xindeng Zhengzhou Cement Co., Ltd. , Zhengzhou Henan 452470, China |
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Abstract A 4 500t/d cement clinker production line uses nonferrous metal ash as iron raw material. The content of water-soluble chromium (VI) in cement clinker produced in 2024 is as high as 14.30mg/kg, which seriously exceeds the national limit. The reasons for the excessive content of water-soluble chromium (VI) in the production line were analyzed. The content of water-soluble chromium (VI) in cement clinker was reduced to 10.01mg/kg by appropriately reducing the calcination temperature of cement clinker and adjusting the matching of air, coal and material in the rotary kiln system; Further control the content of total chromium in raw materials, use copper slag with low content of total chromium as iron raw material, and add ferrous sulfate reductant with low price and low toxicity in the cement grinding process, so that the content of water-soluble chromium (VI) in outgoing cement is reduced to <6.12mg/kg, which is better than the limit index requirements specified in GB31893-2015 "Limit and determination of water-soluble chromium (VI) content for cement", and has high application value.
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Received: 04 September 2024
Published: 25 May 2025
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