水泥增强磷石膏-膨润土强度及污染物固定的验证

Verification of the Enhancement of the Phosphogypsum-Bentonite Mixture’s Strength and Pollutants Fixation by Cement

膨润土作为磷石膏吸附剂,具有较好的磷(氟)固定效果,但其混合物作为道路填筑材料时,通常无法满足力学性能要求,为探究水泥能否提高磷石膏-膨润土混合物的力学性能,以及能否协同膨润土固定磷石膏中的磷(氟)污染物,制备了掺水泥、不掺水泥以及不同掺量水泥的混合料,压制试样,并分别进行雨水淋滤模拟试验和无侧限抗压强度测试.结果表明:掺加水泥后,试样的无侧限抗压强度以及磷(氟)污染物固定效果均有所提高,在同一养护期下,水泥添加量越多,试样无侧限抗压强度越高,磷(氟)污染物固定效果越好,添加量达到5%时,试样的无侧限抗压强度可达到5.31 MPa,满足《公路路面基层施工技术规范》(JTJ 034—2000)中的要求.本文探究结果成功验证了水泥增强磷石膏-膨润土混合物强度性能及其磷(氟)污染物固定效果的可行性,为磷石膏在道路填筑材料的应用提供了一定的参考价值.

As an adsorbent of phosphogypsum, bentonite has a good effect of fixing phosphorus(fluorine), but as a road filling material, the phosphogypsum-bentonite mixture has poor mechanical properties to meet the requirement of construction. To improve the mechanical properties of the phosphogypsum-bentonite mixture and to explore the cooperative mechanism of cement and bentonite to fix phosphorus(fluorine) pollutants in phosphogypsum, the mixtures with cement, non-cement, and different cement contents were prepared. The rain leaching simulation test and unconfined compressive strength test were carried out respectively for the compacted samples. The results show that the unconfined compressive strength of the sample and the fixation effect of phosphorus(fluorine) pollutants are improved after adding cement. In the same curing period, the more cement is added, the higher the unconfined compressive strength of the sample is, and the better the fixing effect of phosphorus(fluorine) pollutant is. When the addition amount reaches 5%, the unconfined compressive strength of the sample has reached 5.31MPa, which meets the requirements of “Technical Code for Highway Pavement Base Construction”(JTJ034—2000). The results of this paper successfully verified the feasibility of the enhancement of the phosphogypsum-bentonite mixture’s strength and its fixation of phosphorus(fluorine) pollutants by adding cement. It provides a certain reference value for the application of phosphogypsum road-filling materials.