The results of the reclamation of spent moulding sands with inorganic binder in the prototype vibratory reclaimer REGMAS -are presented in the paper. Spent moulding sands with modified water-glass, burned as well as not burned, present in a form of agglomerates (lumps), were subjected to the reclamation processes.During individual reclamation cycles the reclaimer efficiency and vibrations amplitudes were determined and physicalchemical and strength investigations were performed for the obtained reclaim materials. The obtained reclaim was used as a component of the matrix of moulding sands with water-glass in the Floster S technology, in which the reclaim constituted 100%, 80% and 50% of the sand matrix -respectively.Keywords: moulding sand, modified water-glass sand, reclamation, Floster S technology W artykule przedstawiono wyniki regeneracji zużytej masy formierskiej ze spoiwem nieorganicznym w prototypowym regeneratorze wibracyjnym REGMAS. Procesowi regeneracji poddano zarówno masę zużytą ze szkłem wodnym modyfikowanym przepaloną oraz nieprzepaloną masę zużytą występującą w postaci brył.W trakcie realizacji poszczególnych cykli regeneracji określano wydajność regeneratora oraz amplitudę wibracji, dla których przeprowadzono badania fizykochemiczne oraz wytrzymałościowe otrzymanych regeneratów. Wykonano następujące badania: zawartość pyłów w regeneracie U K , analizę sitową osnowy oraz laserową analizę granulometryczną oddzielonych pyłów, odczyn pH, stratę prażenia oraz zawartość Na 2 O regeneratu. Uzyskany regenerat użyto jako składnik osnowy mas formierskich ze szkłem wodnym w technologii floster S, w których stanowił odpowiednio 100%, 80% oraz 50% osnowy piaskowej.
Successful casting demands that during pouring of the foundry mould with molten metal the mould cavity suffers no deformation. This, in turn, demands the use of binding materials that can give the base sand adequate strength. The main bonding materials are clay binders. The foundry industry uses minerals rich in clay, such as kaolinite, halloysite, hydromica, montmorillonite, polygorskite, vermiculite and allophane. Due to their binding capacity, montmorillonites are the most interesting minerals of all the plastic clay rocks. The basic clay rock containing montmorillonite, used as a common binding material for traditional foundry sand mixtures, is bentonite. The domestic demand for raw bentonite materials is almost entirely satisfied by imports from Slovakia, Turkey, Italy, Germany and the Czech Republic, in order of import size. In Poland, the bentonite deposits occur in very small quantities. The exploitation of bentonites is carried out only in the Krzeniów deposit, where they constitute a mineral accompanying basalt. Much more common are bentonite clays containing in addition to smectites also a large amount of other clay minerals. The article presents the results of studies of the physico-chemical and mechanical properties of moulding sand mixtures containing pure bentonite, pure clay or hybrid bentonites which are a bentonite-clay mixture. Melting was also carried out to determine the effect of the type of binder on the surface quality of iron castings.
The results of own studies concerning the application of a new additive to the CO 2 -hardened sodium water glass foundry sands are presented. The new additive, which is a composition of aqueous solutions of modified polyalcohols, has been designated by the symbol "B" and is used as an agent improving the sand knocking out properties. The scope of studies included various mechanical and technological properties of foundry sand mixtures, such as permeability, friability, life cycle of cores and knocking out properties.Two types of water glass with different values of the silica modulus and density, designated as R145 and R150, were tested. Moulding sands used in the tests were made with the additive "B". For comparison, a reference sand mixture with water glass but without the additive "B" was also prepared.
The results of research on the possibility of using a gaseous medium (hot air) as a hardening agent for inorganic binders were discussed, and tests on the reclamation of waste moulding sands were carried out. The research programme also included the use of a modernized test stand for hardening of foundry sands with gaseous agents and a pilot plant for the sand reclamation. Cores made on the test stand were examined for the basic technological properties and were also used in moulds for the trial knocking out of castings. Two types of binders were tested, i.e. a modified water glass designated as Binder A and, for comparison, a reference material which was hydrated sodium silicate R145. The hardener for the sand mixtures was hot air (the dehydration of water glass). Trials of the sand reclamation were carried out in a laboratory pilot plant, installed and operating at the Foundry Research Institute. The obtained reclaim was added in different amounts to the sand mixtures subjected to technological tests. The next step included the manufacture of test moulds, pouring them with aluminium alloy, and knocking out of castings to test the collapsibility of moulds and cores.
The results of investigations of the granulation process of foundry dusts generated in the dry mechanical reclamation process of used sands, where furan resins were binders are presented in the paper. Investigations concerned producing of granules of the determined dimensions and strength parameters. Granules were formed from the dusts mixture consisting in 50 mass% of dusts obtained after the reclamation of the furane sands and in 50 mass % of dusts from sands with bentonite. Dusts from the bentonite sands with water were used as a binder allowing the granulation of after reclamation dusts from the furane sands. The following parameters of the ready final product were determined: moisture content (W), shatter test of granules (Wz) performed directly after the granulation process and after 1, 3, 5, 10 days and nights of seasoning, water-resistance of granules after 24 hours of being immersed in water, surface porosity ep and volumetric porosity ev. In addition the shatter test and water-resistance of granulate dried at a temperature of 105°C were determined. Investigations were performed at the bowl angle of inclination 45°, for three rotational speeds of the bowl being: 10, 15, 20 rpm. For the speed of 10 rpm the granulation tests of dusts mixture after the preliminary mixing in the roller mixer and with the addition of water-glass in the amount of 2% in relation to the amount of dust were carried out. The obtained results indicate that the granulator allows to obtain granules from dusts originated from the reclamations of moulding sands with the furane resin with an addition of dusts from the bentonite sands processing plants.
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