Casting Water Glass Modification Technology And Applied Research

In occupies of the casting share 90% three big molding sands, the sodium silicate granulated substance is reducing the production cost, improves the casting quality, the simplification craft operation, specially aspects and so on environmental protection all have the very big superiority, is most has the possibility to realize the green clean casting, conforms to the 21st century production request molding sand. But this kind of granulated substance also has the water absorbability strongly, is defeated and dispersed the difference, the sodium silicate joins the quantity to cause the sand-out cleaning up difficulty greatly, the old granulated substance sales commission difference question, brings for the sodium silicate granulated substance use and the promotion is very greatly troublesome. Therefore, the development is suitable in the casting production has the high bonding properties and the high anti-water absorbant modified sodium silicate, reduces the molding sand the sodium silicate to join the quantity, is one practical and the imminent question, also is this topic research aim.This article added sodium silicate characteristic, the modified method and the modified mechanism has carried on the comprehensive summary and the analysis. Lies in the elimination take the sodium silicate physical modification to get older, chemistry modification lies in anti-slow aged the guiding ideology as a foundation, has obtained the physical modification mainly is supplies the energy toward the sodium silicate system in, scatters because of the colloidal particle which gets older gets together, causes to gather the silicic acid polymerization degree to uniformize, thus elimination sodium silicate aging; Chemistry modification mainly is introduces the new material to the sodium silicate system in, adsorbs or the' alternation is gathering the silicic acid surface, reduces the surface energy, enhances the stability, reduces gathers the silicic acid further condensation tendency, thus the anti- slow sodium silicate gets older modified method.Under the sodium silicate modified mechanism analysis instruction, has determined the sodium silicate modified plan. The physical aspect uses the pulse electric current adding water glass to carry on the modification. The design has manufactured a set of pulse electric current trigger, by the different voltage, the frequency, the electrode and the pulse process time adds water the glass to carry on modified processing separately, then has conducted the experimental study to its bonding properties, and used the orthogonal cut-and-try method optimal pulse electric current modified sodium silicate the best craft parameter. Chemistry aspect uses the multiple chemistry compound adding water glass to carry on the modification.The research from the organic matter, the inorganic salt, the surface active agent, the nanometer granule four aspects carries on separately, through wants the function analysis and the choice scope exploration to the modifier, has selected four organic matters and three other materials took the multiple chemistry compound modified material, studied them to join the quantity and the sodium silicate performance relations separately, has determined the good modified allocated proportion.In order to further enhance the sodium silicate the comprehensive modified effect, this article proposed the physical - chemistry union modified sodium silicate tentative plan, has conducted the union modified craft research, and used the organic ester hardening and the CO₂ hardening craft has carried on the test to the union modified sodium silicate caking intensity and many-kinds of operational performance.The experimental result indicated that, each kind of modification all can cause the sodium silicate the anti-water absorbability and the caking intensity has the varying degree enhancement, the residual intensity reduces.The union modified sodium silicate is suitable for CO₂ and the organic ester hardening craft, has the good operational performance. In the temperature 23℃, under the humidity 60%RH environment, changes the performance to enhance the CO₂ hardening sodium silicate granulated substance jointly the anti-moisture absorption performance 166.7%, organic ester hardening sodium silicate granulated substance anti-moisture absorption performance 41.7%; In the temperature 25℃, under the humidity 20%RH environment, can make their caking intensity to enhance 78. 3% separately and 58. 2%, the residual intensity reduces 63.7% and 60.0%. The union modification enhanced the sodium silicate anti-water absorbability and cohesiveness effectively, may join in under the guarantee molding sand use intensity premise the organic ester hardening sodium silicate granulated substance sodium silicate the quantity to reduce absolutely joins to the 2.33%, CO₂ hardening sodium silicate granulated substance sodium silicate the quantity to reduce absolutely 3.89%, the residual intensity drops 2/3.Finally, with the transmission electron microscope, the infrared spectroscope, equipment and so on scanning electron microscope to used the different method modified sodium silicate to carry on the observation and the analysis. The examination result has further confirmed the author the accuracy which analyzes to each kind of modified mechanism.