钒钛铁尾矿基高强烧结透水砖的制备及性能

Preparation and properties of high-strength fired water permeable brick containing vanadium-titanium iron ore tailings

以钒钛铁尾矿为主要原料制备高强烧结透水砖,采用正交试验法、X射线衍射(XRD)、扫描电镜(SEM)和能谱分析(EDS)研究了钒钛铁尾矿高强烧结透水砖的基本性能、烧结机理。结果表明,当烧结透水砖中钒钛铁尾矿掺量为77%,烧结温度为1070℃,保温时间110 min时,烧制的产品抗压强度和透水系数分别达到65.7 MPa和0.063 cm/s,符合《透水砖》(JC/T 945-2005)中Cc60级产品的要求;高强烧结透水砖烧结后的产物为透辉石(CaMgSi_(2)O_(6))和普通辉石(Ca(Mg,Fe,Al)(Si,Al)_(2)O_(6))。随着烧结温度和保温时间的延长,低熔点元素P、Na、K溶出,烧结产物中Fe、Al元素的含量增多,透辉石中的多数Ca^(2+)被Fe^(3+)置换,使得普通辉石成为主晶相。烧结产物中的孔洞随着烧结温度的提高,发生了由大小不一的密闭孔→孔径不规则的联通孔→不规则塌陷孔→孔径小且均匀圆形孔的变化,这种变化为高强烧结透水砖的透水性提供了保障。该研究提高了钒钛铁尾矿的利用率,为钒钛铁尾矿的大规模应用提供了新途径。

In order to promote the efficient comprehensive utilization of vanadium-titanium iron ore tailings(VTIOTs),the basic properties and firing mechanism of high-strength fired water permeable bricks(HSFWPB)containing VTIOTs were investigated by using orthogonal test method,X-ray diffraction(XRD),scanning electron microscopy(SEM)and energy spectrum analysis(EDS).The results show that when the content of VTIOTs in HSFWPB is 77%,the firing temperature(FT)is 1070℃and the holding time is 110 min,the compressive strength and permeability coefficient of the fired product reach 65.7 MPa and 0.063 cm/s,respectively,which meet the requirements of Cc60 grade products set by“water permeable brick”standard(JC/T 945—2005).The products of HSFWPB containing VTIOTs after firing are diopside(CaMgSi_(2)O_(6))and augite(Ca(Mg,Fe,Al)(Si,Al)_(2)O_(6)).With the increase of FT and the extension of HT,the low melting point elements of P,Na,K dissolve out,and the contents of Fe and Al in the firing products increase;most of Ca^(2+)in diopside is replaced by Fe^(3+),and thus,augite becomes the main crystal phase.With the increase of FT,the pores in the fired products change as follows:closed holes with different sizes→connected pores with irregular diameters→irregular collapse pores→small and uniform circular pores,which provides a guarantee for the permeability of HSFWPB containing VTIOTs.The research has improved the utilization rate of VTIOTs and provides a new approach for the large-scale application of VTIOTs.