Recovery of iron by jarosite crystallization and separation of vanadium by solvent extraction with extractant 7101 from titanium white waste liquid (TWWL)

The jarosite crystallization and new extractant system for extractant 7101 was used to separate iron and extract vanadium from titanium white waste liquid (TWWL). The influence factors and mechanisms of crystallization and solvent extraction were investigated and analyzed using SEM-EDS, XRD, FT-IR, solution thermodynamic theory and extraction isothermal curve. More than 97% of iron was precipitated with the following conditions: potassium chlorate 15 g/L, pH value of 1.6, temperature of 95 °C and time of 90 min, in which the crystallization product was jarosite with a purity of 99.5%; the pH value of the solution decreased after precipitation. The extraction efficiency of vanadium reached 88.6% with 10% Fe, 5% Al(III) but less for Mg(II), K(I) and Na(I) under the conditions X7101 of 0.5, pH value of 2.0, time of 4 min and stirring speed of 40 r/min. The extraction of metal ions occurred in the order V(V) > Fe(III) > Al(III) > Mg(II) > K(I). Vanadium minimally existed as at pH 2.0, and the functional groups NH and C–N contributed to vanadium extraction using the extractant 7101. Four stages extraction and three stages of re-extraction were predicated by McCable–Thiele plots.

ANALISIS PENGARUH SUHU MINYAK KELAPA SAWIT (CPO) TERHADAP NILAI TAHANAN TERMAL MEMPERGUNAKAN PEMODELAN KURVA I(V) ISOTERMAL SENSOR PTC

PTC level sensor for overfill protection works based on the thermal resistance (Rw). The sensor cannot identify high-temperature fluid in the container and determine the pump switching status “ON” and “OFF”. This is due to the influence of the medium temperature on the Rw. Analysis is performed by observing the Rw value of crude palm oil (CPO) as a result of the storage temperature. The Rw value was obtained from the modeling of I (U) sensor curve of EPCOS B59050D1100 with temperature variations ranging from 20°C to 80°C. The modeled area is then determined using the isothermal curve and is resulted Rw value of 110.2K/W. The ambient temperature influence on Rw can be modeled after polynomial equation. Compare to the previous air measurement, the thermal resistance in CPO has 62.6% vary than in the air. This value can be used to determine the position of the level sensor switch safely. Keywords: level sensors, PTC, thermal resistance, CPO, isothermal

Preparation of Carboxymethylcellulose Picric Acid Ester and Adsorption Property for Creatinine

Ether of carboxymethylcellulose-based picric acid(CMC-PA) was prepared from carboxymethylcellulose(CMC) and picric acid(PA) by the mild reactive conditions of acidylation with chloric.The strcture of CMC-PA was characterized by FTIR,Element analysis,XRD and CPMAS13C NMR.Influences of reaction conditions,such as reaction temperature,reaction time,ratio of CMC to PA and amount of pyridine,were studied by mass fraction of nitrogen.Result showed that the synthetical conditions were obtained as ratio of CMC to PA 2 : 1 (by weight),amount of pyridine 50 mL,reaction temperature 85°C and reaction time 4 hours.The adsorption property of CMC-PA to creatinine was studied under simulated biological human body conditons.The kinetic and isothermal curve were given. Results showed that adsorption amount reached an equilibrium value after 10 hours,and the maximum adsorption amount was 1.75mg/g.Equilibrium data of creatinine fit well with Freundich equation,indicating that the adsorption was mainly chemical monolayer adsorption .The Freundich indx(1/n) was less than 1,which implied that the adsorption was preferential process.

Isothermal Curve Determination in Water to Air Concentric Tube Exchanger Using Finite Difference Method

This paper discuss the heat tranfer in the concentric tube with numerical solution. Hot water flow in the inner tube and the force circulation of air has been used to absorb the heat from the inner tube in paralel direction. Kosasih and Koestoer [7] compared the result of experimental research and the numerical calculation of temperatur distribution in annular space. In this work, the calculation with Pascal Programming in Personal Computer, continue to inner side where hot water flows and the heat passed the wall in between of both side. Isothermal curve has been established by figuring the temperature points and it was depicted using AutoCad.

A Stochastic Approach to Thermal Modeling Applied to Electro-Discharge Machining

The usual method of making some simplifying assumptions and formulating thermal models that yield results confirmed by experiments does not work in many cases where the problem is complex and random. Electro-Discharge Machining (EDM) is such a process that is not only complicated and random but also physically little understood. The paper illustrates thermal modeling of this process with the help of a recently developed stochastic methodology called Data Dependent Systems (DDS). An equation to the melting iosthermal curve is defined from the DDS (stochastic empirical) model obtained from readily measurable surface profiles of actual machined surfaces created by the random superposition of electrical discharges. This equation of the melting isothermal curve is then combined with the heat conduction equation, under rather realistic and intuitively obvious assumptions, to develop a transient temperature distribution. The form of this (hybrid) thermal model is mathematically much simpler and yet its predictions are much closer to the experimental results, compared to the complicated models proposed in the literature.

The statistical mechanics of condensing systems

J. E. Mayer (1937) has published, together with some collaborators, several papers under the same title as the present one. We consider these papers as a most important contribution to statistical mechanics, and this opinion was shared by the International Conference held in Amsterdam, 26 November 1937, in commemoration of Van der Waals’ birth. One of the present authors gave to this meeting a report on Mayer’s work (published in Physica, 1937) which was followed by a vigorous dis­cussion on the question as to whether Mayer’s explanation of the pheno­mena of condensation is correct. Doubts about this point were raised by the referee, because it is difficult to comprehend how a method of approxi­mation such as that of Mayer, starting from the gaseous state, can lead to the discontinuity of the density on an isothermal curve which corresponds to condensation. The usual methods for treating the equilibrium of two phases introduce the equation of state of both phases and derive the con­dition for their co-existence. Mayer’s theory does nothing of this kind, but treats all possible molecular arrangements with their proper weight, as if there were only one phase. How can the gas molecules “know” when they have to coagulate to form a liquid or solid? Mayer’s mathematical method is too involved to make this point quite clear.