铅羟基磷灰石等矿物是磷酸盐稳定垃圾焚烧飞灰体系后形成的含铅磷酸盐新矿物相.实验研究了PO34-与不同摩尔比的铅离子(XPb)之间化学反应形成不同磷酸盐新相的控制条件,并对产物的晶体结构、形貌、热稳定性及化学稳定性进行了探讨.结果表明,pH为10的条件下,随着XPb的增加,合成产物依次为Ca8Pb2(PO4)6(OH)2,Ca5.5Pb4.5(PO4)6(OH)2,Ca2.12Pb2.22(PO4)3(OH)0.67,Ca2Pb8(PO4)6(OH)2和Pb10(PO4)6(OH)2;产物亦由棒状聚合体向颗粒状集合体、块状集合体转变.而且产物在400℃以下均可稳定存在;产物中铅的TCLP浸出浓度随着浸取液pH的升高而逐渐降低,且当XPb=0.1-0.7时,产物均具有良好的化学稳定性,当XPb增大到一定程度时,其化学稳定性则逐渐降低.
Lead-hydroxyapatite was a new mineral phase of lead-bearing phosphate formed from the stabilization of fly ash treated by phosphate. The control conditions of the formation of various new phosphates from reaction between PO4 ^3- and lead ions (Xpb) in terms of different molar ratios were studied. The products' characteristics, thermal behaviors and chemical stability were also discussed. It is indicated that Ca8 Pb2 ( PO4 ) 6 ( OH)2, Ca5.5 Pb4.5 ( PO4 ) 6 ( OH )2, Ca2.12 Pb2.22 ( PO4 )3 ( OH ) 0.67, Ca2 Pb8 ( PO4 )6 ( OH)2 and Pblo (PO4 )6 (OH)2 are synthesised respectively with the increase of Xpb at the pH value of 10. And the products are changed from clavate polymer, granulated aggregate to massive aggregate. Furthermore, they can exist stably below 400~C. The lead leached via TCLP are decreased with the increase of the pH value of leaching solution. When the Xpb is in the range from 0.1 to 0.7, the products perform good chemical stability. However, the stability is weakened when the Xpb is above 0.7.