Han Fei,Cao Mei,Lin Jiali,Liu Ting,Zhu Xiaoyun,Zhang Yan
The stability and dispersion of Copper (Cu) powders in an aqueous medium impacts their performances. Thus the Cu powder suspensions were prepared by adding different stabilizers—sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), polyvinyl pyrrolidone (PVP), and hexadecyl trimethyl ammonium bromide (CTAB); the best surfactant was selected and its stability and dispersion were studied. The study systematically examined the effect of the stability of suspensions via sedimentation analysis, including solid–liquid ratio, the concentration of stabilizer, and dispersion time. The particle size, the stability of suspensions, phase composition, and microstructure of Cu powders were characterized by laser particle size analyzer, zeta potential, X-ray diffraction (XRD), transmission electron microscope (TEM), and scanning electron microscope (SEM). The results indicate that the stability of the suspension is improved with the addition of PVP due to the steric hindrance of PVP, and the growth and agglomeration of particles are retarded by the formation of a thick hydration layer with the optimizing concentrations, dispersion time, and solid–liquid ratio 10 g/L, 30 min, and 1:25, respectively.
Li Xuejie,Peng Zhigang,Feng Qian,Zheng Yong,Zhang Xiaofeng,Zhang Haojun,Long Yu,Zhang Yunao,Zhou Jun
To address the excessive retardation of oil well cement caused by polycarboxylate dispersants (PCE), this study synthesized a zwitterionic polycarboxylate dispersant (DPC). Its molecular structure and weight were characterized using 1 H nuclear magnetic resonance and gel permeation chromatography, respectively. The dispersion effect of DPC in cement slurries was evaluated by analyzing microstates, particle size distribution, Zeta potential, and rheological properties, and compared with acetone formaldehyde sulfite condensates (AFS) and conventional anionic polycarboxylate dispersants (CPC). The influence of DPC on cement hydration was studied through thickening performance, compressive strength, semi-adiabatic calorimetry, and X-ray diffraction. DPC effectively disrupted particle flocculation in cement slurry, reducing the median particle size from 34.4 μm to 10.2 μm. At a dosage of 0.20%, the slurry with DPC exhibited superior flowability compared to CPC and AFS. DPC induced Newtonian fluid behavior with weaker thixotropy and significantly reduced retardation effects. The 24-h compressive strength of cement stones reached 39.7 MPa, the thickening time was about 83 min, and the hydration heat peak occurred earlier. Adsorption studies indicated that DPC disperses through steric hindrance and the synergistic anchoring effects of cations and anions. Overall, DPC demonstrates high dispersibility and lower retardation, making it a promising additive for oil and gas well cementing.
危险品化学品经营许可证（带存储）