Phosphogypsum (PG) is a large environmental issue generated by phosphate fertilizer industries. Its annual disposal worldwide is about 160 million tons, representing a high risk of contamination of the environment. The content of dihydrate (CaSO₄.2H₂O) in PG is generally above 90%, presenting recycling potential in cement production. The objective of this research is to investigate the applicability of unprocessed PG in the composition of sustainable ternary cement (TC) containing Portland cement (PC) and wastes of marble and clay brick. The effects on hydration properties and phase contents of PG added in ratios 1, 3, 5, and 10 wt% to cement were studied. The technical feasibility of applying PG in TC with different WCB/WM ratios (2.0 and 3.6) was also evaluated. Isothermal calorimetry was applied to study the hydration kinetics of the TC pastes. The hydration products were evaluated using Fourier transform infrared spectroscopy (FTIR), thermal analysis (TG/DTG/DTA), and X-ray diffractometry using the Rietveld method. The evolution of axial compressive strength was assessed at ages 1, 3, 7, 28, and 91 days. The increase in PG content satisfactorily prolonged the cement setting time and the induction period. Phosphorus impurities in the form of CaHPO₄.2H₂O did not cause any deleterious effects in the first hours of hydration. Although the presence of PG affects the hydration reactions by leading to higher levels of hydrated calcium silicate (C-S-H) and monocarboaluminate (Mca). TC pastes are mainly composed of C-S-H gel, portlandite, ettringite, Mca, calcite, quartz, dolomite, β-belite, and periclase. TC pastes after 28 days reached at least 70% of the PC compressive strength. The WCB/WM ratio affected the compressive strength, although it did not significantly influence the formation of phases. By evaluating the properties of TC paste it was concluded that the unprocessed PG can sustainably be used as an alternative to a natural source of calcium sulfate in the manufacture of the ternary cement.

磷石膏（PG）是磷肥行业产生的一个巨大的环境问题。其在全世界的年处置量约为1.6亿吨，这代表着污染环境的高风险。二水合物（CaSO ₄ .2H ₂PG中的O）通常高于90％，在水泥生产中具有回收潜力。这项研究的目的是研究未加工的PG在含硅酸盐水泥（PC）的可持续三元水泥（TC）以及大理石和粘土砖废料的组成中的适用性。研究了以1、3、5和10 wt％的比例添加到水泥中的PG对水合性能和相含量的影响。还评估了在具有不同WCB / WM比（2.0和3.6）的TC中应用PG的技术可行性。等温量热法用于研究TC糊的水合动力学。使用傅里叶变换红外光谱（FTIR），热分析（TG / DTG / DTA）和使用Rietveld方法的X射线衍射法评估水合产物。在1、3、7岁时评估了轴向抗压强度的变化。28天和91天。PG含量的增加令人满意地延长了水泥凝结时间和诱导期。CaHPO形式的磷杂质₄ .2H ₂ O在水合作用的最初几个小时内没有造成任何有害影响。尽管PG的存在通过导致更高水平的水合硅酸钙（CSH）和单碳铝酸盐（Mca）来影响水合反应。TC糊剂主要由CSH凝胶，硅酸盐，钙矾石，Mca，方解石，石英，白云石，β-贝利石和钙镁石组成。28天后，TC糊剂至少达到了PC抗压强度的70％。WCB / WM比影响抗压强度，尽管它并没有显着影响相的形成。通过评估TC浆料的性能，得出的结论是，未加工的PG可以可持续地用作三元水泥生产中天然硫酸钙来源的替代品。