In this work, an assessment and comparison of the quality of selected bentonites and bentonite mixtures was made. The samples consisted of available foundry materials used for bonding green sands. Determining the homogeneity degree and specific surface area of the grains allowed us to compare the examined materials and determine their influence on other parameters. On the basis of a thermal analysis of the bentonites or bentonite mixtures, the changes occurring in the sample during its heating were determined. Determining the potential for ion exchange and montmorillonite content enabled us to assess the binding properties of the materials. The preparation of six green sands with different bentonites or bentonite mixtures gave us the opportunity to assess the changes in apparent density, permeability, compressive strength and friability as a function of humidity, and the impact of different materials on the mentioned parameters. Their charts were analyzed, and the molding sand with the addition of bentonite or a bentonite mixture was selected for which these parameters are favorable. On this basis, the best-presented binding material was assessed and selected.
Until now, the mould sand in general use in the foundry industry are based on bentonite, which resulted from the fact that a good recognition properties and phenomena associated with this material. Come to know and normalized content of montmorillonite and carbonates and their important role in the construction of bentonite, and mass properties of the participation of compressive strength or scatter. Halloysite is widely used in industry and beyond them. However, little is known about its use in the foundry in Poland and abroad. This article presents preliminary research conducted at the Foundry Department of Silesian University of Technology on this material. Will raise the question of the representation of this two materials, which contains information connected with history and formation of materials, their structure and chemical composition. In the research, the results of compressive strength tests in wet masses of quartz matrix, where as a binder is used halloysite and bentonite in different proportions.
Bentonites and clays are included in the group of drilling fluids materials. The raw materials are mainly clay minerals, which are divided into several groups, like montmorillonite, kaolinite, illite, biotite, muscovite, nontronite, anorthoclase, microcline, sanidine or rutile, differing in chemical composition and crystal lattice structure. Clay minerals have a layered structure forming sheet units. The layers merge into sheets that build up to form the structure of the mineral.
The aim of the studies carried out in the ŁUKASIEWICZ Research Network - Foundry Research Institute is to explore the possibility of using minerals coming from Polish deposits.
The article outlines the basic properties of hybrid bentonites, which are a mixture of bentonite clay called beidellite, originating from overburden deposits of the Turoszów Mine, and foundry bentonite from one of the Slovak deposits. As part of the physico-chemical tests of minerals, measurements included in the PN-85/H-11003 standard, i.e. montmorillonite content, water content and swelling index, were carried out. Additionally, the loss on ignition and pH chemical reaction were determined. Based on the thermal analysis of raw materials, carried out in the temperature range from 0 to 1000oC, changes occurring in these materials during heating, i.e. thermal stability in contact with liquid metal, were determined.
Examinations of the sand mixture based on pure clay and bentonite and of the sand mixture based on hybrid bentonites enabled tracing changes in permeability, compressive strength and tensile strength in the transformation zone as well as compactability referred to the clay content in sand mixture. Selected technological and strength parameters of synthetic sands are crucial for the foundry, because they significantly affect the quality of the finished casting.
Based on the analysis of the results, the optimal composition of hybrid bentonite was selected.
Bentonite is clay rock, which is created by decomposition of vulcanic glass. It is formed from mixture of clay minerals of smectite group,
mainly montmorillonite, beidellite and nontronite. Its typical characteristics is, that when in contact with water, it intensively swells. First
who used this term was W.C. Knight in 1887. The rock had been named after town Fort Benton in American state Montana. For its
interesting technological properties and whiteness has wide technological use. Bentonite is selectively mined and according to its final use
separately modified, which results in high quality product with specific parameters.
In the beginning of 21st century belong bentonite moulding mixtures in foundry to always perspective. Mainly increased ratio of ductile
cast iron castings production cannot be ensured without the need of quality bentonite. Great area of scope remains to further research of
moulding materials, which return also to bentonite producers.
The aim of this study was to evaluate the effect of high doses of calcium bentonite on the blood parameters, anticoccidial activity and intestinal histology of broiler chickens. Three undred and sixty one-day old broilers were distributed into three treatments (T+VE, T-VE, TB )with three replicates. Amprolium was added to the feed of the positive control group, calcium bentonite powder was added to the TB group, and nothing was added to the feed of the T-VE group. Coccidiosis was induced on day 14, the birds were kept until day 49, measurements of the diffe- rent variables started from week 3, blood samples were collected via wing vein, and fecal oocysts were counted from the intestinal contents of each individual bird using the McMaster techni- que. A decrease in feed consumption, body weight gain and conversion ratio was noticed in the calcium bentonite group. Broilers in the calcium bentonite group (TB ) and negative control group (T-VE ) showed clinical signs of coccidiosis (blood in feces) and the number of oocysts in feces increased with time. Histopathological examinations of the affected caeca also demonstrated excessive tissue damage, hemorrhage, the presence of clusters of large schizonts and merozoites in the tissue, and coccidian oocysts in the lumen. Feed conversion was highest in the T+VE group.
Zinc (II) removal using low-cost sorbents requires a proper process parametric study to determine
its optimal performance characteristics. In this respect, the present study proposes a new modeling and simulation procedure for heavy metal removal system and is carried out to optimize input variables such as initial pH,
adsorbent dosage, and contact time for biosorption of Zinc (II) by using bentonite. The proposed experimental
system is cost-effective and requires less calculation for determining optimal values, i.e., input variables and
their related removal capacity, Rem%. To optimize the adsorption process, cubic spline curve fitting and numerical differentiation techniques are used for required calculations. According to the proposed calculations, the
removal capacity is calculated as 98.66%, while the optimal values are calculated as initial pH – 6.76, adsorbent
dosage – 1.14 g L-1, contact time – 13 minutes. To evaluate the results, full factor experimental design and 3 way
ANOVA test are used for comparison.
A determination of the heating degree of the moulding sand with bentonite on the grounds of simulating investigations with the application of the MAGMA program, constitutes the contents of the paper. To this end the numerical simulation of the temperature distribution in the virtual casting mould was performed. It was assumed that the mould cavity was filled with a moulding sand with bentonite of a moisture content 3,2 % and bentonite content 8 %. A computer simulation can be used for predicting the heating degree of moulding sands with bentonite. Thus, prediction of the active bentonite (montmorillonite) content in individual layers of the overheated moulding sand can be done by means of the simulation. An overheating degree of a moulding sand with bentonite, and thus the bentonite deactivation depends on a temperature of a casting alloy, casting mass, ratio of: masssand : masscasting, moulding sand amount in the mould and contact area: metal – mould (geometry of the casting shape). Generally it can be stated, that the bentonite deactivation degree depends on two main factors: temperature of moulding sand heating and time of its operation.
The paper presents results of measuring thermal conductivity and heat capacity of bentonite foundry sand in temperature range ambient –
900 OC. During the experiments a technical purity Cu plate was cast into the green-sand moulds. Basing on measurements of the mould
temperature field during the solidification of the casting, the temperature relationships of the measured properties were evaluated. It was
confirmed that water vaporization strongly influences thermal conductivity of the moulding sand in the first period of the mould heating by
the poured casting.
This study explores the influence of alkali activators on the initiation of polymerization reaction of alumino-silicate minerals present in class-F fly ash material. Different types of fly ash aggregates were produced with silicate rich binders (bentonite and metakaolin) and the effect of alkali activators on the strength gain properties were analyzed. A comprehensive examination on its physical and mechanical properties of the various artificial fly ash aggregates has been carried out systematically. A pelletizer machine was fabricated in this study to produce aggregate pellets from fly ash. The efficiency and strength of pellets was improved by mixing fly ash with different binder materials such as ground granulated blast furnace slag (GGBS), metakaolin and bentonite. Further, the activation of fly ash binders was done using sodium hydroxide for improving its binding properties. Concrete mixes were designed and prepared with the different fly ash based aggregates containing different ingredients. Hardened concrete specimens after sufficient curing was tested for assessing the mechanical properties of different types concrete mixes. Test results indicated that fly ash -GGBS aggregates (30S2‒100) with alkali activator at 10M exhibited highest crushing strength containing of 22.81 MPa. Similarly, the concrete mix with 20% fly ash-GGBS based aggregate reported a highest compressive strength of 31.98 MPa. The fly ash based aggregates containing different binders was found to possess adequate engineering properties which can be suggested for moderate construction works.
In the last few years, cationic layered clays, including bentonites have been investigated as potential catalysts for SCR DeNOx systems. In this work, bentonite as the representative of layered clays was modified in order to obtain an alternative, low-cost NH3–SCR catalyst. Samples of raw clay were activated with HCl or HNO3, treated with C2H2O4 and subsequently pillared with alumina by the ion- exchange. Afterwards, the modified materials were impregnated with iron and copper. The obtained catalysts were characterized by XRD and FT-IR. SCR catalytic tests carried out over analyzed samples indicated the conversion of NO of approximately 90% for the most active sample. The type of acid used for modification and the type of active phase strongly influenced the catalytic properties of the analyzed materials.