The investigation results of the influence of the reclaim additions on the properties of moulding sands with the GEOPOL geopolymer

binder developed by the SAND TEAM Company were presented. Two brands of hardeners were applied in the tested compositions, the

first one was developed by the SAND TEAM Company, marked SA72 and the new hardener offered by the KRATOS Company, marked

KR72. The main purpose of investigations was to determine the influence of reclaim fractions and the applied hardener on the basic

moulding sands properties, such as: bending and tensile strength, permeability and grindability. The unfavourable influence of the reclaim

additions into moulding sands on the tested properties as well as an increased hardening rate, were found. Moulding sands, in which the

hardener KR72 of the KRATOS Company was used, were less sensitive to the reclaim additions.

The results of investigations of moulding sands with an inorganic binder called GEOPOL, developed by the SAND TEAM Company are

presented in the paper. Hardeners of various hardening rates are used for moulding sands with this binder. The main aim of investigations

was determination of the influence of the hardening rate of moulding sands with the GEOPOL binder on technological properties of these

sands (bending strength, tensile strength, permeability and grindability). In addition, the final strength of moulding sands of the selected

compositions was determined by two methods: by splitting strength and shear strength measurements. No essential influence of the

hardening rate on such parameters as: permeability, grindability and final strength was found. However, the sand in which the slowest

hardener (SA 72) were used, after 1 hour of holding, had the tensile and bending strength practically zero. Thus, the time needed for taking

to pieces the mould made of such moulding sand will be 1.5 - 2 hours.

One of the factors that contribute to the development of foundry moulding technology is environmental protection. The related challenges are effectively satisfied by a new inorganic binder that has been designed for castings made of non-ferrous metal alloys. This article presents in a concise way the test results, showing the ecological character of the new binder at the stage of making moulds, pouring them with metal and cooling of castings, indicating the possibilities for an economic re-use of waste materials formed during practical application of this technology. The results were compared with the results obtained on the sands with organic binders. Studies were carried out under the project POIG.01.01.02-00-015/09 "Advanced materials and technologies."

A thermo-insulating moulding sand with a binder made of aluminosilicate microspheres with organic binder was subjected to testing. The aim of the analysis was to determine selected technological properties of the developed compounds. Compressive strength, friability and gas permeability were determined. The binder content was changed within a range of 5÷20 wt% with a 5% step. The applied matrix is characterized by good thermo-insulating properties and a small size of grains, while synthetic organic binder has favourable functional properties, among which the most noteworthy are the extended life and setting time, good rheological properties as well as high resistance to chemical agents. The intended use of the compound is the casting of 3D CRS (Composite Reinforced Skeletons), which are characterized by a well-developed heat transfer surface area, good absorption of impact energy, low mass and a target thickness of connectors within a range of 1.5÷3 mm. The construction of 3D CRS castings is an original concept developed by the employees of the Department of Foundry Engineering at the Silesian University of Technology.