In accordance with this invention a binder composition for treating particulate material to form a solid aggregate matrix is prepared by providing a urea formaldehyde precondensate; a polar solvent; additional urea; an acid or salt thereof, the acid or salt thereof being selected such as to render the pH of the binder composition to a value from 2.0 to 5.3; providing a sugar; providing a binding promoter for enhancing the binding between the binder composition and the particulate material; and mixing the above so as to form a binder composition. The binder composition is mixed with particulate material and allowed to set into a solid aggregate matrix over a period of longer than 30 minutes from being mixed with the said particulate material.