Liquid Chromium Research Articles

Reference Correlations for the Density and Thermal Conductivity, and Review of the Viscosity Measurements, of Liquid Titanium, Zirconium, Hafnium, Vanadium, Niobium, Tantalum, Chromium, Molybdenum, and Tungsten

The available experimental data for the density, thermal conductivity, and viscosity of liquid titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten have been critically examined with the intention of establishing reference correlations. All experimental data have been categorized into primary and secondary data according to the quality of measurement, the technique employed, and the presentation of the data, as specified by a series of criteria. In the case of the density, new reference correlations are proposed for liquid titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten, characterized by an expanded uncertainty (95 %) of 2.0 %, 2.1 %, 1.9 %, 2.2 %, 2.4 %, 2.6 %, 3.2 %, 2.1 %, and 4.1 %, respectively. The thermal conductivity reference correlations for the aforementioned liquid metals, except liquid chromium, are characterized by an expanded uncertainty (95 %) of 14.3 %, 8.4 %, 6.1 %, 11.4 %, 7.6 %, 4.0 %, 4.6 %, and 5.1 %, respectively. Finally, in the case of the viscosity, a review of the available literature shows very large deviations between data from authors for liquid titanium and zirconium, as well as a lack of measurements for the remaining melts. Hence, it is not justified to propose any kind of correlation for those cases.

On the solubility of gases in liquid casting alloys

It has been shown that hydrogen and oxygen atoms cannot be present in the open pores of crystal lattices of base metals of casting alloys. The solubility of gases in liquid casting alloys is a nanostructured process. Hydrogen and oxygen atoms in melts are adsorbed by basic metal elemental nanocrystals. Nitrogen dissolves in liquid iron, nickel and chromium not in atomic form, but in the composition of elementary nanocrystals and nitride molecules. After deoxidation of molten casting alloys, the main gas dissolved in them is hydrogen.

Wagner interaction coefficient between nitrogen and chromium in liquid nickel-based alloys

The authors propose a simple theory of thermodynamic properties of nitrogen solutions in liquid Ni–Cr alloys. This theory is completely analogous to the theory for liquid nitrogen solutions in alloys of the Fe–Cr and Fe –Mn systems proposed previously by the authors in 2019 and 2020. The theory is based on lattice model of the Ni–Cr solutions. The model assumes FCC lattice. In the sites of this lattice are the atoms of Ni and Cr. Nitrogen atoms are located in octahedral interstices. The nitrogen atom interacts only with the metal atoms located in the lattice sites neighboring to it. This interaction is pairwise. It is assumed that the energy of this interaction depends neither on the composition nor on the temperature. It is supposed that the solutions in the Ni–Cr system are perfect. Within the framework of the proposed theory, a relation is obtained that expresses the Wagner interaction coefficient between nitrogen and chromium in liquid nickel-based alloys. The right-hand part of the appropriate formula is a function of ratio of the Sieverts law constants for solubility of nitrogen in liquid chromium and nickel. The values of these constants for the temperature of 1873 K are assumed to be K′(Cr) = 15,2; K′(Ni) = 0,0015 wt. %. An estimate is obtained for the Wagner interaction coefficient in nickel-based alloys = 21,4. This corresponds to the value of the Langenberg interaction coefficient = –0,105, wich is very close to the experimental estimates = –0,108 for the temperature of 1873 K (Surovoi et al., 1971) and = –0,11 for the temperature of 1823 K (Stomakhin at al., 1965).

Toxic Metals in Liquid and Aerosol from Pod-Type Electronic Cigarettes.

High-quality, accurate data on liquid contents and aerosol emissions from electronic nicotine delivery systems (ENDS, e.g., e-cigarettes) are crucial to address potential health concerns as these devices evolve and mature. Metals are an important class of ENDS constituents that merit attention as they have various health implications. Proper sampling, handling and aerosol trapping materials are essential to generate accurate quantitative metal data and to reduce the likelihood of inaccurate results originating from inappropriate collection vessels and materials that contribute to high background levels. Published methods that meet these criteria were applied to the analyses of chromium, nickel, copper, zinc, cadmium, tin and lead in liquid and aerosol from mint/menthol and tobacco flavors of currently popular pod-based devices from three manufacturers. Metal concentrations from pods that had not been used for generating aerosol ranged from below our lowest reportable level to 0.164 µg/g for Cr, 61.3 µg/g for Ni, 927 µg/g for Cu, 14.9 µg/g for Zn, 58.2 µg/g for Sn and 2.56 µg/g for Pb. Cadmium was included in our analyte panel and was not present above detection limits in liquid or aerosol. Aerosol metal concentrations (using a 55-mL puff) ranged from below our lowest reportable level to 29.9 ng/10 puffs for Cr, 373 ng/10 puffs for Ni, 209 ng/10 puffs for Cu, 4,580 ng/10 puffs for Zn, 127 ng/10 puffs for Sn and 463 ng/10 puffs for Pb. Our results showed some metal delivery from all the products examined and highly variable metal levels between manufacturer, brand and package.

Using spent tea residue to elimination of chromium in aqueous liquid

In this work, spent red and black tea form leaves were assessed for their ability to doff expel chromium ion from aqueous solutions at various values of PH. Classification adsorption experiments indebted at choice temperature and showed cruise the adsorption of Cr ion decrease more the increase of temperature. In successive lyrics, the adsorption fight is exothermic and the enthalpy is fatal, at long last the unconventional ways and the entropy are positive. The matter copied at equal stat was compared with Langmuir, Freundlich models, and the inference efficiencies for Cr ion higher than 99% and can easily be achieved. It was hinge saunter the brilliant hatch is reform than hyacinthine cause in adsorption of chromium ion.

Environmental health impact assessment of chrome composite leather-clad rollers used by Indian cotton roller ginning industries and design and development of Eco-friendly alternatives

This research article realises the hazards of chromium contamination and pollution caused by using chrome composite leather-clad (CCLC) rollers that are commonly used in the cotton roller ginning industries and attempts to eliminate the chromium contamination and pollution during the cotton ginning process. The chromium traces found contain hexavalent chromium being adsorbed from chromium-contaminated lint, yarn, fabrics, seeds, by-products and textile effluent. Chromium acts in three ways on humans, viz. (i) local action explained as dermatitis or absorption through skin, (ii) direct inhalation and (iii) ingestion or absorption into the stomach. Toxic effects are produced by prolonged contact with airborne or solid or liquid chromium compounds even in small quantities because of their properties, viz. carcinogenicity, mutagenicity and corrosiveness. Traces of Cr (VI) are found even in analar grade trivalent compounds, and complications do arise due to reduction in the nature of these traces that affect the organic tissues of the body. These regenerating effects occur rapidly and are dependent on the dose. This research article realises the hazards of chromium contamination and pollution caused by the use of dust-producing grinding of CCLC rollers that are commonly used in the cotton roller ginning industries and attempts to nullify this problem during cotton ginning. This research has been carried out with the following objectives: to identify and study the environmental health effects existing with the present CCLC rollers being used in the Indian cotton roller ginning industries; to conduct an environmental health impact assessment in Indian cotton roller ginning factories during the research years of 1998–2018; to design and develop an eco-friendly chrome-free roller and evaluate its performance with reference to environmental health effects and techno-commercial aspects in the ginning industries. With the author’s research background and practical experience in cotton ginning and textile industries, this study is attempted to eliminate the environmental health impacts to a great extent at the source itself, through a suitable design and development of an eco-friendly, pollution-free, chromeless roller for cotton roller gins. An eco-friendly roller ginning process has been designed and developed for replacing the conventional CCLC roller ginning process, to eliminate the chromium contamination and pollution from cotton roller ginning industries and to meet the requirements of World Health Organisation standards, while maintaining high-quality spun yarns and woven fabrics which meet the international standards.
 
 Keywords: Assessment, chromium, ginning, health, impact.

Stability of the liquid markers chromium (III) and cobalt (III)-EDTA in autoclaved, clarified rumen fluid

An ideal digesta marker for use in feeding studies is inert, unabsorbable, and moves with the portion of the digesta it is intended to mark. Both chromium (III) and cobalt (III) salts of EDTA (CrEDTA and CoEDTA, respectively) have been used as digesta liquid markers in studies with dairy cattle. Although a small portion of these markers is known to be absorbed and excreted in urine, the markers are assumed to remain ionically bound in the digesta. The degree to which these salts remain bound in solution can be determined through spectrophotometric measurement at the wavelength (λ) of peak absorbance of these colored compounds. The objective of this study was to evaluate whether CrEDTA and CoEDTA dissociate during incubation in autoclaved, clarified rumen fluid (ACRF), as indicated by changes in absorbance. In a complete block design with separate replicated analytical runs, approximately 40 mg/L of Cr from CrEDTA or Co from CoEDTA were incubated in 2 separate preparations of ACRF from 2 lactating Holstein cows, in water (CrEDTA), or in MES buffer (CoEDTA), and appropriate reagent blanks. Solution pH were approximately 6.0. Samples were incubated for 24 h at 39°C with absorbance measurements recorded at 0, 1, 2, 4, 6, 22, and 24. The CrEDTA was measured at λ = 541 nm, CoEDTA at λ = 535 nm, and both were measured with wavescans of λ = 330 to 700 nm. At their peak λ, both CrEDTA in water and CoEDTA in MES buffer maintained absorbance values throughout the incubation, whereas, in ACRF, CrEDTA absorbance decreased by 9% at 0 h, and by up to 14% by 24 h; CoEDTA showed a gradual decline over time, with approximately 4% loss in absorbance by 24 h. Responses differed by ACRF preparation. Both markers in ACRF showed increases and decreases over time in absorbance at λ = 330 and 380 nm, though the changes were more marked for CrEDTA; markers not in ACRF showed no change in absorbance at these λ. Changes in the absorbance values at λ = 330 and 380 nm suggest that soluble phenolic compounds may be involved in the exchange of metals with EDTA, but that does not preclude involvement of other components in rumen fluid. Both CrEDTA and CoEDTA incubated in ACRF showed declines over time in absorbance at their peak λ, suggesting that the metals dissociated from EDTA. The apparent dissociation indicates that these liquid markers are not inert as had been assumed.

Liquid digesta markers: A method for synthesis of crystallized chromium-EDTA and comparison of its degree of complexation with an uncrystallized preparation

Markers of liquid digesta are an essential tool for determination of in vivo nutrient digestibility and passage as they move with and mark passage of the liquid fraction through the gut. Such markers are ideally biologically and chemically unreactive so they do not affect the digesta or animal. Two issues encountered with the liquid marker chromium (III) (Cr) ethylenediaminetetraacetic acid (EDTA; Cr-EDTA): 1) the Cr acetate·monohydrate required for preparation of the crystallized lithium salt of Cr-EDTA (Li·Cr-EDTA; Udén method; J. Sci. Food Agric. 31, 1980, 625–632) has become largely unavailable, and 2) as an ionic salt, the degree of complexation of Cr and EDTA in solution of an uncrystallized preparation of Cr-EDTA has not been evaluated. Accordingly, the objectives of this study were to develop a method for preparing Li·Cr-EDTA using Cr (III) acetate hydroxide, and to compare the degree to which Cr is complexed with EDTA in solutions made with crystallized Li·Cr-EDTA and in preparations in which Cr-EDTA is not crystallized for purification (Binnerts method; Vet. Rec. 82, 1968. 470). The new Li·Cr-EDTA preparation method which uses Cr acetate hydroxide gave product yields of 901 to 870 g actual/kg theoretical which was similar to the 900 g actual/kg theoretical yield reported for the original Udén method. The Cr concentrations were 928–961 g actual/kg theoretical for the salt. Solutions of both the crystallized preparation of Li·Cr-EDTA and the liquid preparation of the Binnerts method gave visibly similar absorbance patterns at wavelengths from 300 to 750 nm and showed maximum light absorption at 541 nm, the reported wavelength of maximum absorption for Cr-EDTA. Comparison of absorbances at 541 nm to a Li·Cr-EDTA generated standard curve showed that uncrystallized Cr-EDTA produced with the Binnerts method gave a recovery of Cr in Cr-EDTA of approximately 993 g/kg, which did not differ from the 992 g/kg value for preparations of Li·Cr-EDTA; this indicates that Cr and EDTA for both preparation methods were almost completely complexed in solution. In conclusion, the new method for preparing Li·Cr-EDTA gave results comparable to the Udén method, and Cr and EDTA were ionically bound to a high degree and comparably in both the uncrystallized solution of the Binnerts method and solutions of crystallized Li·Cr-EDTA. Verification of the degree of Cr and EDTA complexation in Binnerts preparations can be accomplished with spectrophotometric comparison against a purified standard such as Li·Cr-EDTA.

Thermodynamics of Liquid Solutions of Nitrogen in Chromium

A simple theory is proposed for the thermodynamic properties of nitrogen solutions in Fe–Cr melts. The theory is based on a lattice model of the solution. An fcc model lattice is adopted. Iron and chromium atoms are distributed at the lattice sites. Nitrogen atoms are located in octahedral interstices. The nitrogen atoms only interact with metal atoms at neighboring lattice sites. The energy of this interaction is assumed to depend neither on the composition nor on the temperature. The liquid Fe–Cr solutions are assumed perfect. Within this framework, the constant in the Sieverts law governing the solubility of nitrogen in liquid chromium may be expressed in terms of its value for the solubility of nitrogen in liquid iron and the value of the Wagner parameter for N–Cr interaction in liquid iron alloys. In addition, the partial enthalpy of solution of nitrogen in liquid chromium at infinite dilution is expressed in terms of the corresponding enthalpy for the solution of nitrogen in liquid iron and the Wagner parameter for N–Cr interaction in liquid iron alloys. A relation is also established between the Wagner parameter for N–Fe interaction in liquid chromium alloys and the Wagner parameter for N–Cr interaction in liquid iron alloys. On that basis, the constant in the Sieverts law governing the solubility of nitrogen in liquid chromium is calculated, along with enthalpy of solution of nitrogen in liquid chromium at infinite dilution and the Wagner parameter for N‒Fe interaction in liquid chromium alloys at 1873 K. The calculation results are compared with experimental data regarding the solubility of nitrogen in liquid chromium and Cr–Fe alloys obtained by various methods. The theoretical data are in best agreement with experimental data obtained by quenching. The values of the Wagner parameter for N–N interaction in liquid chromium alloys and iron alloys are discussed.

Water hyacinth cellulose-based membrane for adsorption of liquid waste dyes and chromium

Water hyacinth (Eichornia crassipes) is a weed in aquatic area whose trunk contains a lot of cellulose. Cellulose contained can be used as dyes adsorbent in a form of composite membrane. This study aims to investigate the capacity of water hyacinth cellulose-based membrane to adsorb dye and Chromium (Cr) contained in liquid. The process of membrane fabrication begins with isolation of water hyacinth cellulose. The isolated cellulose powder was used to make the membrane by mixing it with polyvinyl alcohol-polyethylene glycol (PVA-PEG) with various compositions. The morphology of membrane surface was analyzed using CCD microscope. The analysis using Ultraviolet Visible Spectroscopy (UV-Vis) and Atomic Absorption Spectroscopy (AAS) indicate that the membrane with composition ratio of cellulose: PVA: PEG of 6.5: 2.5: 1 adsorb Cr up to 38.75%.

Solid State Manufacture of High Entropy Alloys-Preliminary Studies

For the past ten years Metalysis have produced tantalum, titanium and titanium alloy powders for high performance applications using their solid state salt electrolysis process. This low energy and environmentally friendly process is now being used to manufacture the next generation of High Entropy Alloys (HEAs). In most cases the manufacture of HEAs involves high temperatures which put all of the alloying elements into the liquid phase. This can lead to numerous problems and restrict the number of HEAs which can be made, particularly the alloys where one needs to combine low melting point elements with refractory elements and also where there are significant liquid density differences between the constituents causing melt segregation. The aim is to present the preliminary work carried out by Metalysis and to show how the solid state diffusion process based on molten salt electrolysis lends itself to the industrial scale manufacture of the next generation of HEAs. This study will focus on the HEAs whose constituent alloying elements have large differences in both their melting points and liquid densities, for example, chromium, niobium, tantalum, titanium and aluminum.

Temperature dependence of ultrasound absorption in liquid metals in terms of classical and quantum theories

The equation of coefficient of ultrasound absorption is substantiated in terms of classical and quantum theories. Polytherms for liquid gold, scandium, chromium, and rhenium in a wide temperature range have been obtained for the first time.

Description Of Alloy Layer Formation On A Cast Steel Substrate

Abstract A description of alloy layer formation on a steel substrate is presented. Two types of formation are considered: diffusion of carbon and chromium into the solid from the pad in the direction of the cast steel within the FeCrC (grains) and diffusion in a layer of liquid chromium cast iron formed in a preceding step. The influence of silicon in the pad on the pad’s transformation into the liquid is also examined. Solidus and liquidus temperatures of high carbon ferrochromium are determined. The larger the content of Si is used in the experiment, the lower the solidus temperature of the FeCrC alloy is observed. This results from the higher intensity of the elements’ diffusion and faster formation of the liquid.

Physical metallurgy and physicochemical behavior of high-temperature chromium alloys. Part II. Assessing the thermodynamics of metallurgical processes in chromium-based melts

In view of the lack of experimental data regarding the thermodynamic behavior of elements in chromium-based melts, data for iron-based melts are adapted appropriately. Results are tabulated for the heat of solution of elements in liquid chromium, the activity coefficients of these elements, their molar reaction parameters, and the ΔG r ∘ values for reduction processes and also for nitride, carbide, sulfide, and boride formation in chromium melts. Recommendations are made regarding the selection of strengthening phases in chromium alloys.

Examples of Catalytic and Selective Routes for Fluorinated Building Blocks

Examples are presented for the catalytic fluorination of chlorinated starting materials in order to produce building blocks or HFCs. The fluorination of CF3CH2Cl, of CCl2═CCl2, of trichloromethoxylbenzenes and trichloromethoxybenzene involving nucleophilic substitution are reported. In all cases, HF was the fluorinating agent. Depending on the chlorinated substrate and the degree of fluorination required, liquid- or gas-phase processes were involved. Usually, catalysts were SbCl5 in liquid phase and chromium oxide in gas phase. In the presence of SbCl5, at 90 °C under an initial pressure of 10 bar, the fluorination of CCl2═CCl2 leads mainly to the formation of CClF2CHCl2, and the active catalyst is an antimony mixed halide (SbCl3F2). In the same way, the presence of SbCl5 favored the formation of 1-trifluoromethyl-3-trichloromethylbenzene from bis-1,3-trichloromethylbenzene at low temperature (50 °C) and in the presence of a low amount of HF. Moreover, trichloromethoxybenzene was totally transformed into ...

51.3: Design for Reducing Autostereoscopic Display Crosstalk using a Liquid Crystal Gradient‐index Lens

AbstractA 2D/3D switchable liquid crystal display with low crosstalk of 0.9% is developed using a liquid crystal gradient‐index lens. The low crosstalk is achieved with a design approach using low‐birefringence liquid crystal and chromium electrodes as a light shield.

Study on coated–liquid–liquid trimetal composite casting hammer

In order to solve the problems of the fracture of the hammer head and the poor wear resistant of hammer handle in working conditions, the coated liquid–liquid trimetallic composite casting hammer was proposed. The core handler needed to be coated by high impact toughness and high wear resistant liquid high carbon high chromium steel to improve wear resistant of hammer handle. Then liquid high chromium cast iron was poured when the surface of liquid high carbon high chromium steel formed into certain thickness solid. The experimental results show that the wear resistant of the high carbon high chromium is as 3·2 times as low alloy steel. The perfect metallurgical bonding interface under the liquid–solid volume ratio of 8∶1 can be achieved by liquid–solid casting at 1565°C after the preheating 300°C.

Thermodynamic modeling of the Cr – S system

Abstract All known phases of the chromium – sulfur binary system have been taken into consideration within a thorough thermodynamic analysis of phase equilibria and thermodynamic data at 1 bar total pressure over the entire composition range between 25 °C and temperatures above the liquidus. Gibbs energy modeling for ten phases has been performed. A limited set of model quantities were optimized by which the experimental data can be reproduced simultaneously within experimental limits of error. New interpretations of complex phase relations are obtained. The extended modified quasichemical model is applied for the liquid chromium – sulfur phase. The Gibbs energy of high-temperature chromium pyrrhotite solution is described by a two-sublattice model within the framework of the compound energy formalism. The sulfur solubility of solid chromium is modeled using a substitutional approach. The Gibbs energies of six stoichiometric compounds are also modeled. The first internally consistent description of all thermodynamically stable phases known in the literature for the chromium – sulfur system is presented.

The Activity of Nitrogen in the Liquid Fe-N-Cr Alloy Based on the Non-Random Solubility Model by Schmid - Fetzer

The values of nitrogen solubility in the liquid Fe-N-Cr alloy and in liquid chromium were determined experimentally. The alloy of a chromium content of 8; 13; 18; 25; 35; and 69, respectively, and chromium of purity of 99.7 wt % were subjected to experiment. The original data on nitrogen solubility in liquid iron and the data on nitrogen solubility in liquid chromium (the authors' own studies) were converted in relation to the new standard state that is represented by pure nitrogen. The energy parameter, h Fe-Cr, was determined based on literature data. Using the coefficient values for the Fe-Cr alloy, calculated on the basis of our own investigation results, the values of the energy parameter h were determined. The determined energy parameter h in the form of a temperature function relationship will enable the determination of the numerical values of the for the Fe-Cr alloy of any arbitrary composition.

Carrier element-free coprecipitation (CEFC) method for the separation, preconcentration and speciation of chromium using an isatin derivative

A new, simple, rapid and sensitive separation, preconcentration and speciation procedure for chromium in environmental liquid and solid samples has been established. The present speciation procedure for Cr(III) and Cr(VI) is based on combination of carrier element-free coprecipitation (CEFC) and flame atomic absorption spectrometric (FAAS) determinations. In this method a newly synthesized organic coprecipitant, 5-chloro-3-[4-(trifluoromethoxy) phenylimino]indolin-2-one (CFMEPI), was used without adding any carrier element for coprecipitation of chromium(III). After reduction of chromium(VI) by concentrated H 2SO 4 and ethanol, the procedure was applied for the determination of total chromium. Chromium(VI) was calculated as the difference between the amount of total chromium and chromium(III). The optimum conditions for coprecipitation and speciation processes were investigated on several commonly tested experimental parameters, such as pH of the solution, amount of coprecipitant, sample volume, etc. No considerable interference was observed from the other investigated anions and cations, which may be found in natural water samples. The preconcentration factor was found to be 40. The detection limit for chromium(III) corresponding to three times the standard deviation of the blank ( N = 10) was found 0.7 μg L −1. The present procedure was successfully applied for speciation of chromium in several liquid and solid environmental samples. In order to support the accuracy of the method, the certified reference materials (CRM-TMDW-500 Drinking Water and CRM-SA-C Sandy Soil C) were analyzed, and standard APDC-MIBK liquid-liquid extraction method was performed. The results obtained were in good agreement with the certified values.