The herein paper contains the results of investigations on a new type of cellulose blend used for the manufacture of profiles applied in the
process of making gating systems in the foundry industry. A standard cellulose profile was subjected to an experiment. During the
experiment the profile was filled with a liquid cast iron and at the same time the temperatures of the liquid metal crystallizing inside the
profile were measured as well as the temperature of the outer layer of the profile was controlled. Further, the microstructure of the cast
iron, which crystallized out inside the cellulose profile, was analysed and the cellulose, thermally degraded after the experiment, was
verified with the use of the chemical analysis method. Moreover, a quality analysis of the original as well as the degraded cellulose profile
was run with the use of the FTIR infrared spectroscopy. The presented results revealed that the cellulose blend is aluminium silicate
enriched and contains organic binder additives. The cast iron, which crystallized out, tended to have an equilibrium pearlitic structure with
the release of graphite and carbides. The generation of disequilibrium ausferrite phases was also observed in the structure.
Chalcedonite is a diatomaceous sedimentary rock, which, on account of a very small occurrence area, is included into a group of unique rocks. It occurs at Dęborzynka, Gapinin, Lubocz and Teofilów deposits, located on the Rawska Plateau in the region of Tomaszów Mazowiecki and Nowe Miasto. The deposit in Teofilów is the only documented one and it is now being exploited. The surface of this deposit is 577 437 m2 and its geological resources were determined to be 21.587 - 106 kg (21 587.0 thousand tones). The main component of this rock is chalcedon (69.0-96.6 vol.%), however quartz, opal, iron hydroxides, pyrite, manganese compounds and clay minerals occur in small quantities. The active surface of chalcedonite is relatively small and it was determined as 3-6 m2/g. Chalcedonite had a mesoporous structure of a significantly high pore homogeneity, and the total volume of these pores was 0.03-0.04 cm3/g. On account of its small spatial distribution chalcedonite is a unique rock, which has multi-resource properties. It is useful for manufacturing perlite-like material, crystobalite, wollastonite and mullite. It was also found to be a valuable raw material for the production of pastes, scouring powders, grinder tools and also as good filler for the production of : paints, varnishes, enamel ware, lute and putty materials. Because of its mesoporous structure and due to extended outer surface of the grains, chalcedonite is utilized in water treatment technology, mostly as an effective filtration material. A high usefulness of chalcedonite bed for manganese and iron removal from water shows mostly the presence of a low height of iron removal zone in the filter, and it is also manifested by a relatively short time of introduction into effective manganese(II) removal, as well as by good hydraulic properties of the material, which enable to achieve high mass capacities of the filter and to reach long filtration cycles. Chalcedonit is a very good carrier of manganese oxides and its surface modification of leads to the creation of chemically active bed, which enables removal of manganese(II) from water with high efficiency and without the introduction process. Chalcedonite bed effective removes of ammonia nitrogen from the water in the process of nitrification and waste water treatment. Chalcedonite can be also taken into account as a sorbent for the removal of oil spills.
The paper presents the results of preliminary research on the application of olivine moulding sands with hydrated sodium silicate containing 1.5 % wt. of binder to perform ecological casting cores in hot-box technology using a semi-automatic core shooter. The following parameters were used in the process of core shooting: initial shot pressure of 6 bar, shot time 3 s, the temperature of the corebox: 200, 250 and 300 °C and the core curing time: 30, 60, 90, 120 and 150 s. The matrix of the moulding mixture was olivine sand, and the binder of the sandmix was commercial, unmodified hydrated sodium silicate with molar module SiO2/Na2O of 2.5. In one shot of the automatic core-shooter were formed three longitudinal specimens (cores) with a dimensions 22.2×22.2×180 mm. The samples obtained in this way were subjected to the assessment of the influence of the shooting parameters, i.e. shooting time, temperature and curing time in core-box, using the following criteria: core box fill rate, mechanical strength to bending Rg U, apparent density, compaction degree and susceptibility to friability of sand grains after hardening. The results of trials on the use of olivine moulding sands with hydrated sodium silicate (olivine SSBS) in the process of core shooting made it possible to determine the conditions for further research on the improvement of inorganic hot-box process technology aimed at: reduction of the heating temperature and the curing time. It was found that correlation between the parameters of the shooting process and the bending strength of olivine moulding sands with sodium silicate is observed.
Minerals were analysed that had been found in penguin guano and in underlying silicate weathering crust phosphatized by guano leachates. Struvite and hydroxylapatite were found in guano, leucophosphite, minyulite, amorphous aluminum phosphate and taranakite in phosphatized layer, and in some distance from the zone of ornithogenic soils — vivianite. Minerals were identified by the X—ray analysis and results of this identification were confirmed by the microscope studies and the analysis of chemical composition. Results of the thermogravimetric analysis of the selected minerals occurring in monomineral agglomerations (struvite, minyulite, amorphous aluminum phosphate, taranakite) are also presented. Relation between distribution of those minerals in ornithogenic soils and changes in chemical composition of mineral-forming guano leachates during their infiltration through soil, were described.
The ablation casting technology consists in pouring castings in single-use moulds made from the mixture of sand and water-soluble binder. After pouring the mould with liquid metal the mould is destructed (washed out) using a stream of cooling medium, which in this case is water. The process takes place while the casting is still solidifying.
The following paper focuses on testing the influence of the modified ablation casting of aluminum alloy on casts properties produced in moulds with hydrated sodium silicate binder. The authors showed that the best kind of moulding sands for Al alloy casting will be those hardened with physical factors – through dehydration. The analysis of literature data and own research have shown that the moulding sand with hydrated sodium silicate hardened by dehydration is characterized by sufficient strength properties for the modified ablation casting of Al alloys. In the paper the use of microwave hardened moulding sands has been proposed.
The moulds were prepared in the matrix specially designed for this technology. Two castings from the AlSi7Mg alloy were made; one by traditional gravity casting and the other by gravity casting using ablation.
The conducted casts tests showed that the casting made in modified ablation casting technology characterizes by higher mechanical properties than the casting made in traditional casting technology. In both experimental castings the directional solidification was observed, however in casting made by ablation casting, dimensions of dendrites in the structure at appropriate levels were smaller.
Silicate coatings have been considered as an alternative to toxic and carcinogenic other chemical treatments. In this paper, a strengthened silicate coating was formed on the surface of low carbon steel by dip immersion method. The modification and strengthening was done by loading colloidal nano-SiO2 into the film. The characterizations of nano-SiO2 were investigated by FESEM, TEM and FT-IR. The effects of nano contents (weight ratio) and drying temperatures on corrosion properties of silicate film were studied. Potentiodynamic polarization, electrochemical impedance spectroscopy and immersion tests have been used to study corrosion behavior of nano-loaded silicate films. Surface morphology, microstructure and its chemical composition were analyzed by means of FESEM, EDS, AFM, XRD, GIXRD, ATR-FTIR and Raman techniques. Results indicated that colloidal nano-SiO2 properly modified the silicate coatings and significantly improved the corrosion resistance and barrier property. Also drying temperature showed a considerable effect in silicate coating and higher corrosion resistance was obtained with 150°C curing.
Erbium-doped lead silicate glass has been investigated for near-infrared emission and up-conversion applications. Near-infrared emission due to 4I13/2 → 4I15/2 transition of Er3+ is relatively broad (70.5 nm) and long-lived (3.7 ms). Also, up-conversion luminescence spectra of Er3+ ions in lead silicate glass have been examined as a function of temperature. The relative intensities of luminescence bands corresponding to 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of Er3+ were determined with temperature. The fluorescence intensity ratio and temperature sensitivity were calculated. The maximum sensitivity for Er3+ doped lead silicate glass is close to 26.4 × 10−4 K−1 at T = 590 K.
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