Yellow clays from Moroccan phosphate mines are extracted with other waste rocks lithologies and stored in large dumps within the mine site. The present paper investigates the use of this by-product as a new aluminosilicate source for geopolymers elaboration at the laboratory scale. Yellow clays studied are mainly composed of montmorillonite, dolomite and quartz as major phases. The Toxicity Characteristic Leaching Procedure (TCLP) showed no existence of contaminant. In order to reach thermal activation, the raw clays were first calcined at different temperatures between 500 and 900 °C. Raw and calcined clays were characterized using thermogravimetric analysis (TGA), X-Ray Diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. For the synthesis of geopolymers, calcined powder was mixed with an alkaline solution presenting different NaOH/Na₂SiO₃ ratios. The compressive strength was measured at 7, 14 and 28 days and material porosity was determined using Mercury Intrusion Porosimetry method in order to explain the mechanical behavior. XRD, ²⁷Al and ²⁹Si Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR) spectroscopy, Fourier transformed infrared and TGA have been used to investigate the gel structure.

The thermal treatment at 900 °C allowed the destruction of crystalline structure of montmorillonite clays, as well as the formation of new phases such as periclase (MgO) and gehlenite (Ca₂Al₂SiO₇). Furthermore, the ²⁷Al - ²⁹Si MAS-NMR and the XRD analysis of the elaborated materials confirmed the formation of two cementitious gels C-A-S-H (Calcium aluminum silicate hydrate) and N-A-S-H (Sodium aluminum silicate hydrate). The compressive strength was around 25 MPa at 28 days. The obtained results are promising; they have shown that elaborated materials can be adapted for construction applications. In this case, it is recommended that economic and commercial study be developed.

来自摩洛哥磷酸盐矿的黄色粘土与其他废石岩性一起被提取，并被储存在矿场内的大型垃圾场中。本文研究了这种副产物作为新型铝硅酸盐来源在实验室规模内用于地质聚合物加工的用途。研究的黄色粘土主要由蒙脱石，白云石和石英组成。毒性特征浸出程序（TCLP）显示不存在污染物。为了达到热活化，首先在500至900°C之间的不同温度下煅烧生粘土。使用热重分析（TGA），X射线衍射（XRD）和傅立叶变换红外（FTIR）光谱对生粘土和煅烧粘土进行表征。对于合成地聚合物，₂ SiO ₃比率。在第7、14和28天测量抗压强度，并使用Mercury Intrusion Porosimetry方法确定材料的孔隙率，以解释其机械性能。XRD，²⁷ Al和²⁹ Si幻角旋转核磁共振（MAS-NMR）光谱，傅立叶变换红外光谱和TGA已用于研究凝胶结构。

在900°C的热处理可以破坏蒙脱石粘土的晶体结构，并形成新相，例如长钙镁矿（MgO）和钠钙石（Ca ₂ Al ₂ SiO ₇）。此外，²⁷ Al- ²⁹ Si MAS-NMR和精细材料的XRD分析证实形成了两种胶凝凝胶CASH（硅酸铝铝水合物）和NASH（硅酸钠铝水合物）。28天的抗压强度约为25MPa。获得的结果是有希望的；他们已经表明，精心制作的材料可以适用于建筑应用。在这种情况下，建议进行经济和商业研究。