Sodium Silicate Sand Dry Regeneration

Speaking of the old granulated substance regeneration, sodium silicate old granulated substance regeneration is relative most difficult, abandons old granulated substance for alkalinity, falls place grass all long, adds on our country high quality quartz sand resources relatively short, if does not add water the glass old granulated substance comprehensive utilization to abandon massively, is to the limited resources enormous waste, moreover creates serious environmental pollution. Therefore, sodium silicate old granulated substance processing and the use have become question which the entire society urgently awaits to be solved.This article has carried on the comprehensive analysis and the research in view of the sodium silicate old granulated substance nature, the union stuck the conjunctiva, the hardened membrane, the inert membrane relations has developed the exploration sodium silicate inert thin film and the regeneration way correlational dependence research, then unifies the old granulated substance regeneration mechanism to have the pointed choice appropriate regeneration method adding sodium silicate bonded old granulated substance to carry on relatively different regeneration processing, to green sand for castings from the casting convention performance, a grain of appearance carries on the appraisal again, according to cast used steel sodium silicate bonded sand (core) granulated substance production request, to green sand for castings the development optimization craft experiment, the consideration again green sand for castings satisfies the production request again the degree and the feasibility, the confirmation regeneration craft regeneration effect, its final goal is enables again green sand for castings completely or the part substitution new sand modelling, the system core, reduces the old granulated substance emissions.The used sodium silicate bonded sand surface film and the nature research indicates : 1) The used sodium silicate bonded sand after hardened membranes are the hardened membrane which the crystal and the amorphous body compose together, mainly by amorphous state acid gelatin and few tan oak quartz crystal,Na₂CO₃·7H₂O crystal compositions; The acid gelatin hardening membrane transforms in the being heated function after the inert membrane, mainly for the acid gelatin inert membrane and the few crystal, the crystal of Na₂SiO₃·9H₂O (rhombic system), has provided the reference for the choice regeneration method;2) Sodium silicate granulated substance drying hardens the after hard membrane is the hardened membrane which the crystal and the composes together, mainly is composed by the amorphous body and the few crystals; The silicate hardening membrane transforms after the being heated function as the silicate inert membrane.The adding used sodium silicate bonded sand granulated substance sand grain surface inert thin film and the nature research indicated, The sodium silicate (core) the granulated substance different hardening craft and the sodium silicate inert membrane has certain relation, unifies the old granulated substance regeneration mechanism according to the inert membrane nature to have the pointed choice appropriate regeneration method to carry on regeneration processing to the old granulated substance.The adding used sodium silicate bonded sand granulated substance carries on relatively different regeneration processing the experiment to indicate, the mechanical agitation heating - impact - friction attrition regeneration experiment and the microwave heating - impact - friction attrition regeneration experiment speaking of again green sand for castings the sodium oxide content, all may reduce the old granulated substance the sodium oxide content, among them, old granulated substance sodium oxide content 0 .446%, the mechanical agitation heating - impact - friction wears green sand for castings the sodium oxide content to be again lowest may be 0.1333%, the microwave heating - impact - friction wears green sand for castings the sodium oxide content to be again lowest may be 0.207%. The heating way to both regeneration effect influence difference is not differently very big, but because time the former heating the continuously agitation causes the old granulated substance sand grains to rub mutually, played to a certain extent the primary regeneration role, therefore regeneration effect the former surpasses the latter. Indicated through the orthogonal experiment, the old granulated substance heating temperature is to regenerates the effect influence to be big, further explained in the sodium silicate old granulated substance sand grains quartz grain the inflation and sodium silicate inert membrane brittleness which causes along with the heating temperature ascension enhances, under the contraction together function, may enhance the regeneration effect.Considered carries on the reason through the heating method adding sodium silicate bonded on the old granulated substance which the regeneration must consume energy, uses the friction attrition regeneration method adding used sodium silicate bonded granulated substance to carry on the regeneration, this green sand for castings uses in the sodium silicate caking dosage-form (core) the granulated substance craft experiment formula optimization experiment indicating again, in green sand for castings joins the quantity is again 100%, the sodium silicate joins the quantity is 5% and the carbon dioxide air flush time under 10s technological conditions, molding sand compressive strength big 0.9Mpa, may achieve the production the request.