利用磷酸镁水泥固化富集型重金属铜和镍研究

利用磷酸镁水泥对富集型重金属铜和镍进行固化研究。对掺入硝酸铜和硝酸镍水泥的抗压强度、铜镍离子浸出质量浓度、水化产物组成等进行测定,观测水泥表面的微观形貌,分析铜镍离子在水泥中的化学态及赋存状态。研究表明：硝酸铜掺量为0~3%（质量分数）时,水泥的抗压强度随着铜离子掺量的增加呈现先增大后减小的趋势,当硝酸铜掺量为1%时,水泥7 d抗压强度达到最大值46.05 MPa;硝酸镍掺量为0~3%（质量分数）时,水泥的抗压强度随着镍离子掺量的增加而逐渐减小,当硝酸镍掺量由0增加到3%时,水泥7 d的抗压强度降低了约29%。水泥的密实度与铜镍离子的固化效果直接相关。在硝酸铜和硝酸镍掺量都为3%时,水泥1 d铜离子浸出质量浓度最高为1.95 mg/L、镍离子浸出质量浓度最高为0.97 mg/L,均远低于相关国家标准。铜主要以+2价态的Mg_0.95Cu_0.05O形式存在,镍主要以+2价态的Ni（OH）₂无定形沉淀形式存在。

Study on solidification mechanism of MPC for enrichment heavy metals Cu and Ni

MPC（magnesium phosphate cement） was used to solidificate enrichment heavy metal Cu and Ni. The compressive strength of MPC added Cu（NO₃）₂ and Ni（NO₃）₂,the leaching concentration of Cu ²⁺ and Ni ²⁺,and the composition of hydration products were determined.The surface microstructure was observed.The chemical states and occurrence of Cu ²⁺ and Ni ²⁺ in cement were analyzed.Results showed that when content of Cu ²⁺ increased from 0 to 3%（mass fraction）,the compressive strength of cement increased first and then decreased with the increase of Cu ²⁺ content;the 7 d compressive strength reached the maximum value of 46.05 MPa,when the dosage of Cu ²⁺ was 1%.When the content of Ni ²⁺ increased from 0 to 3%（mass fraction）,the the compressive strength of cement decreased gradually with the content of Ni ²⁺ increased,and the 7d compressive strength decreased about 29%.The compactness of cement was directly related to the curing effect of Cu ²⁺ and Ni ²⁺.When the dosage of Cu ²⁺and Ni ²⁺ was both 3%,the maximum leaching concentration of Cu ²⁺ was 1.95 mg/L,and Ni ²⁺ was 0.97 mg/L,both far below the relevant national standards. Cu mainly exists in the form of Mg_0.95Cu0_.05O of +2,and Ni exists in the form of Ni（OH）₂ amorphous precipitation of +2.