A refractory composition is disclosed comprising a high purity silicon dioxide and a binder. This refractory composition may be applied by trowelling, brushing, casting, pumping and/or spraying it on a worn and/or damaged high purity silica refractory surface. A refractory castable composition is also disclosed that may be employed with forms. Further, an essentially non-slumping, sprayable refractory castable composition that is applied without the use of forms is provided. The sprayable refractory castable composition comprises (a) a tempered, pumpable first component comprising (i) a high purity silicon dioxide and a binder, and (ii) water, if needed, to achieve a pumpable consistency, and (b) a second component comprising a flocculating agent. The flocculating agent is added to the first component for achieving installation of the sprayable refractory composition in an amount to prevent slumping of the sprayable refractory castable composition.