Preparation And Surface Modification Of Nano-barite

Nano-barite, with excellent physicochemical property, has become the focus of the scientific research. Particularly, its particle size, dispersion and diameter distribution are the main process parameters which should be considered.Both Mixed solvents (alcohol, water, etc.) method and complexometry (EDTA, etc.) method, were adopted in the paper to prepare nano-barite. Also, products, prepared under different reaction conditions, were analyzed with different methods, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM).Well dispersed barium sulfate nanoparticles were synthesized through ethanol-water mixed solvents method. It is found that With the increase of the concentration of reactants, the size of product increased and accompanied by reunion phenomenon; Volume of ethanol has a greater influence on the size distribution and the dispersion of the product. Well dispersed barium sulfate nanoparticles were synthesized through EDTA complexometry method, both the concentration of reactants and pH value have an apparent effect on the particle size and distribution of product. It got best morphology and size distribution of barium sulfate nanoparticles when the reaction system pH value at 8.0.The most used weighting agent in oil drilling mud is barite, it has the obvious characteristic of big surface energy, easy to reunite and poor suspension, it is necessary to make a surface modification of barium sulfate to change the isoelectric, enhancing their dispersion and suspension in drilling fluid. Well dispersed barium sulfate nanoparticles were modified by fatty acid with different chain length, barium silicate and silica.The influences of fabrication conditions on the structure, morphology and dispersibility of barium sulfate nanoparticles were characterized by XRD, FT-IR, TEM and particle size distribution curve.Activation index and oil absorption can demonstrate that it has a limited modification effect on barium sulfate composite by different chain length fatty acid. High stirring speed would make the covering film fall off which just coated on the surface of barium sulfate. Also, pH value has a large influence on coated structures and directly affects the existence form of ion. It would form an apparent core-shell structure within the pH range. When pH value is between 9.8 and 10.0, a compact coating layer will form on the modified barium sulfate. And the volume of waterglass is a key factor affects thickness of coating layer. The consequence showed the best product, with good dispersion and apparent coating layer, is when the volume is 40 mL.