粉煤灰漂珠耐静水压强度的测定

Determination of Bulk Strength of Fly-Ash Floating Beads under Hydrostatic Pressure

漂珠为燃煤电厂的副产物,作为减轻剂用于入井作业流体如固井水泥浆时,要受三维静水压力的作用.为此研制了一种静水压力仪,测定了2～40 MPa下两种漂珠的破裂率,作为抗静水压强度的指标,并考察了影响因素.实验漂珠A和B的破裂率在静水压力10 MPa下高达28.27%和20.94%,40 MPa下高达49.37%和41.09%,值得注意.粒径与粒径分布对破裂率无影响.CaO含量较高的漂珠A,X射线衍射曲线上显现CaCO3晶体衍射峰,因此高CaO含量是影响漂珠抗静水压强度的一个非主要因素.主要因素应是漂珠的物理-几何参数,包括壁厚、壁厚均匀度、球形度、表面平滑度、熔合不良产生的局部应力集中等.图5表3参5.

Fly-ash floating beads （FAFB） are created in coal-burning power stations and, when used in downhole working fluids such as well cementing slurries as lightening agent, bear in some cases a high hydrostatic pressure （HSP）. A hydrostatically pressurizing apparatus is worked out, the soundness or rupture rate under HSP in range 2-40 MPa is determined by using this apparatus for two grade of FAFB as a characteristic of HSP bulk strength and the influencing factors are investigated. The rupture rate of commercial FAFB A and B is rather notable, being as high as 28.27% and 20.94% under 10 MPa and 49.37% and 41.09% under 40 MPa. The particle size and size distribution of FAFB are not shown to affect notably the rupture rate. On the powder X diffraction curve of FAFB A with higher CaO content, a peak of crystalline CaCO3 is observed additionally which indicates CaO as a minor factor for rupture of FAFB. The main factors are physlco-geometric characteristics of FAFB such as wall thickness, variance of wall thickness, bead sphericity, surface smoothness and other local stress concentrations.