<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>In this research paper we have determined the enthalpy of the Fe-Ni alloy using the ‘STA’ equipment at the laboratory of the University of Mitrovica “Isa Boletini”, Department of Materials and Metallurgy. The sample for analysis was taken at the Ferronikel plant, whereas the preparation of the sample for analysis on the ‘STA PT 1600’ equipment took place at the laboratory of the University of Mitrovica ‘Isa Boletini’.</p>
<p>The sample of the Fe-Ni alloy analysed was 2–4 cm in size, in the shape of a granule. It contained, 22.55% Ni, 76.51% Fe, and small amounts of other elements [<xref ref-type="bibr" rid="j_rmzmag-2021-0012_ref_001">1</xref>, <xref ref-type="bibr" rid="j_rmzmag-2021-0012_ref_002">2</xref>]. During the analysis of the Fe-Ni alloy, we obtained three enthalpy values under analytical conditions that included a maximum temperature of 800 °C and a minimum temperature of 600 °C; the alloy was exposed to each temperature separately for 45 minutes at each temperature.</p>
<p>The results showed negative enthalpy values during the three scenarios examined and an exothermic process where ΔH&lt;0 [<xref ref-type="bibr" rid="j_rmzmag-2021-0012_ref_003">3</xref>]. The enthalpy decreases as the system releases heat with an increase in temperature [<xref ref-type="bibr" rid="j_rmzmag-2021-0012_ref_004">4</xref>].</p>
</abstract>

In this research paper we have determined the enthalpy of the Fe-Ni alloy using the ‘STA’ equipment at the laboratory of the University of Mitrovica “Isa Boletini”, Department of Materials and Metallurgy. The sample for analysis was taken at the Ferronikel plant, whereas the preparation of the sample for analysis on the ‘STA PT 1600’ equipment took place at the laboratory of the University of Mitrovica ‘Isa Boletini’.
The sample of the Fe-Ni alloy analysed was 2–4 cm in size, in the shape of a granule. It contained, 22.55% Ni, 76.51% Fe, and small amounts of other elements [1, 2]. During the analysis of the Fe-Ni alloy, we obtained three enthalpy values under analytical conditions that included a maximum temperature of 800 °C and a minimum temperature of 600 °C; the alloy was exposed to each temperature separately for 45 minutes at each temperature.
The results showed negative enthalpy values during the three scenarios examined and an exothermic process where ΔH<0 [3]. The enthalpy decreases as the system releases heat with an increase in temperature [4].


<div xmlns="http://www.w3.org/1999/xhtml">
<sec id="j_rmzmag-2021-0012_s_001">
<div>Introduction</div>
<p>Production of Fe-Ni alloy is a difficult process, beginning with the treatment of Fe-Ni ore and involving use of a rotary kiln, an electrical furnace, and finally a converter for the refinement of the metal [<a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_001">1</a>, <a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_005">5</a>]. The costs of fuel for the rotary kiln and the electricity for melting the calcine are high.</p>
<p>The TGA/DSC equipment measures the heat as well as the change in weight of a material as a function of temperature or time in a controlled environment. The simultaneous measurements of these characteristics not only improve productivity, but also simplify the interpretation of results. The data obtained make it possible to differentiate between endothermic and exothermic processes that do not experience weight loss (melting and crystallisation) and those that do experience weight loss (reduction). The simultaneous thermic analyser LINSEIS STA PT 1600 can be used for determining coinciding differences in mass (Tg) and caloric reactions (DSC) of a sample in a 25°C to 1650° temperature range. This simultaneous thermic analyser delivers high accuracy and high resolution. The equipment used for this research is located at the Department of Materials and Metallurgy of the University of Mitrovica ‘Isa Boletini’ (UMIB) and has the following three sensors: TG, TG-DTA, and TG-DSC.</p>
<p>All of the LINSEIS thermo-analytic instruments are controlled from a personal computer (PC). The individual software modules function exclusively using the Microsoft operating system Windows. The software is made up of three modules: temperature control, data acquisition, and data evaluation. The 32-bit program encompasses all fundamental properties for preparing, executing, and evaluating an STA measurement. Thanks to our application experts and specialists, LINSEIS was able to develop a user-friendly, all-inclusive software.</p>
<p>The standard enthalpy of forming a compound is defined as the energy associated with the reaction to form the compound from its constituent elements [<a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_003">3</a>, <a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_004">4</a>]. The standard enthalpy of formation is a basic thermodynamic property that determines its phase stability, which can be coupled with other thermodynamic data to calculate phase diagrams.</p>
</sec>
<sec id="j_rmzmag-2021-0012_s_002">
<div>Materials and methods</div>
<p>We carried out the analysis of the Fe-Ni alloy at the Ferronikel plant’s laboratory in Drenas and obtained the following composition expressed as the percentage of each element [<a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_002">2</a>] (<a ref-type="table" href="#j_rmzmag-2021-0012_tab_001">Table 1</a>):</p>
<table-wrap id="j_rmzmag-2021-0012_tab_001" position="float">
<label>Table 1:</label>
<caption><p>Composition of Fe-Ni alloy [<a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_002">2</a>]</p></caption>
<table frame="void" rules="none">
<thead>
<tr>
<th valign="middle" align="left">Ni</th>
<th valign="middle" align="left">Fe</th>
<th valign="middle" align="left">S</th>
<th valign="middle" align="left">C</th>
<th valign="middle" align="left">Co</th>
<th valign="middle" align="left">P</th>
<th valign="middle" align="left">Si</th>
<th valign="middle" align="left">Cr</th>
<th valign="middle" align="left">Cu</th>
</tr>
</thead>
<tbody>
<tr>
<td valign="middle" align="left">22.55%</td>
<td valign="middle" align="left">76.51%</td>
<td valign="middle" align="left">0.12%</td>
<td valign="middle" align="left">0.01%</td>
<td valign="middle" align="left">0.75%</td>
<td valign="middle" align="left">0.01%</td>
<td valign="middle" align="left">0.01%</td>
<td valign="middle" align="left">0.01%</td>
<td valign="middle" align="left">0.03%</td></tr>
</tbody>
</table>
</table-wrap>
<figure id="j_rmzmag-2021-0012_fig_001" position="float" fig-type="figure">
<h2>Figure 1:</h2>
<figCaption><p>View of a metal casting of refined Fe-Ni.</p></figCaption>
<img xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_rmzmag-2021-0012_fig_001.jpg" src="https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647369f24e662f30ba53d23c/j_rmzmag-2021-0012_fig_001.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&amp;X-Amz-Date=20240524T084611Z&amp;X-Amz-SignedHeaders=host&amp;X-Amz-Expires=18000&amp;X-Amz-Credential=AKIA6AP2G7AKP25APDM2%2F20240524%2Feu-central-1%2Fs3%2Faws4_request&amp;X-Amz-Signature=5432ca543e233cd9786d3f939398f3bdc9d23b395a2463cee62492c0e4af17b4" class="mw-100"/>
</figure>
<figure id="j_rmzmag-2021-0012_fig_002" position="float" fig-type="figure">
<h2>Figure 2:</h2>
<figCaption><p>View of Fe-Ni alloy (granule) [<a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_002">2</a>].</p></figCaption>
<img xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_rmzmag-2021-0012_fig_002.jpg" src="https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647369f24e662f30ba53d23c/j_rmzmag-2021-0012_fig_002.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&amp;X-Amz-Date=20240524T084611Z&amp;X-Amz-SignedHeaders=host&amp;X-Amz-Expires=18000&amp;X-Amz-Credential=AKIA6AP2G7AKP25APDM2%2F20240524%2Feu-central-1%2Fs3%2Faws4_request&amp;X-Amz-Signature=72e000219c5aa0f80f3a22ebebb38189b4f96d15e67206a7cc42c72b0a704fed" class="mw-100"/>
</figure>
<figure id="j_rmzmag-2021-0012_fig_003" position="float" fig-type="figure">
<h2>Figure 3:</h2>
<figCaption><p>Preparation of the sample (UMIB).</p></figCaption>
<img xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_rmzmag-2021-0012_fig_003.jpg" src="https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647369f24e662f30ba53d23c/j_rmzmag-2021-0012_fig_003.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&amp;X-Amz-Date=20240524T084611Z&amp;X-Amz-SignedHeaders=host&amp;X-Amz-Expires=18000&amp;X-Amz-Credential=AKIA6AP2G7AKP25APDM2%2F20240524%2Feu-central-1%2Fs3%2Faws4_request&amp;X-Amz-Signature=ff58c1c136eb4329e9508ababf5a39fc48036a0e6bd1124ed830059c7f147118" class="mw-100"/>
</figure>
<p>The Fe-Ni alloy sample with the composition found in (<a ref-type="table" href="#j_rmzmag-2021-0012_tab_001">Table 1</a>) was prepared at the laboratory of UMIB Department of Materials and Metallurgy. For the preparation of the Fe-Ni alloy sample, we relied on the available parameters of the LINSEIS ‘PT STA 1600’.</p>
<p>The sample has the following parameters:
<list list-type="bullet">
<list-item><p>Length: 4 mm</p></list-item>
<list-item><p>Width: 4 mm</p></list-item>
<list-item><p>Weight: 0.5413 g</p></list-item>
</list></p>
<p>The sample was weighed on an analytical scale (<a ref-type="fig" href="#j_rmzmag-2021-0012_fig_004">Figure 4</a>) at the laboratory of the Faculty of Food Technology (UMIB).</p>
<p>The Fe-Ni alloy sample, after polishing, was placed on the ‘alumina’ plate, and the conditions of the analysis were as follows:
<list list-type="bullet">
<list-item><p>Maximum temperature = 800 °C, for a duration of 45 minutes</p></list-item>
<list-item><p>Minimum temperature = 600 °C, for a duration of 45 minutes</p></list-item>
</list></p>
<figure id="j_rmzmag-2021-0012_fig_004" position="float" fig-type="figure">
<h2>Figure 4:</h2>
<figCaption><p>Measuring weight of the sample on an analytical scale.</p></figCaption>
<img xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_rmzmag-2021-0012_fig_004.jpg" src="https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647369f24e662f30ba53d23c/j_rmzmag-2021-0012_fig_004.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&amp;X-Amz-Date=20240524T084611Z&amp;X-Amz-SignedHeaders=host&amp;X-Amz-Expires=18000&amp;X-Amz-Credential=AKIA6AP2G7AKP25APDM2%2F20240524%2Feu-central-1%2Fs3%2Faws4_request&amp;X-Amz-Signature=0d23db95bc0a02c84d501f99a48308b8906d90451bd98cc64213edb4ee6772f7" class="mw-100"/>
</figure>
<p>The initial temperature is the initial extrapolated temperature of the reaction; the final temperature is the final extrapolated temperature of the reaction. In an exothermic reaction, energy is released because the total energy of the products is lower than the total energy of the reactants. As a result, the change in enthalpy, ΔH, for an exothermic reaction will always be negative. The heat variations in chemical reactions are often measured at the laboratory under conditions in which the reaction system is open to the ambient temperatures. In that case, the system is exposed to constant pressure.<figure id="j_rmzmag-2021-0012_fig_005" position="float" fig-type="figure">
<h2>Figure 5:</h2>
<figCaption><p>LINSEIS PT 1600 (UMIB laboratory).</p></figCaption>
<img xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_rmzmag-2021-0012_fig_005.jpg" src="https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647369f24e662f30ba53d23c/j_rmzmag-2021-0012_fig_005.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&amp;X-Amz-Date=20240524T084611Z&amp;X-Amz-SignedHeaders=host&amp;X-Amz-Expires=18000&amp;X-Amz-Credential=AKIA6AP2G7AKP25APDM2%2F20240524%2Feu-central-1%2Fs3%2Faws4_request&amp;X-Amz-Signature=8ce5e6168c5a0dc30042c45eedd96a5b6b3c93b821c8f458fa997066320f8c42" class="mw-100"/>
</figure>
<figure id="j_rmzmag-2021-0012_fig_006" position="float" fig-type="figure">
<h2>Figure 6:</h2>
<figCaption><p>Determination of the enthalpy of the Fe-Ni alloy in LINSEIS ‘PTSTA 1600’at UMIB.</p></figCaption>
<img xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_rmzmag-2021-0012_fig_006.jpg" src="https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647369f24e662f30ba53d23c/j_rmzmag-2021-0012_fig_006.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&amp;X-Amz-Date=20240524T084611Z&amp;X-Amz-SignedHeaders=host&amp;X-Amz-Expires=18000&amp;X-Amz-Credential=AKIA6AP2G7AKP25APDM2%2F20240524%2Feu-central-1%2Fs3%2Faws4_request&amp;X-Amz-Signature=693c56ced9c3da915431137e9987205b4106a163cfa1614fd6f707bee5ed4e75" class="mw-100"/>
</figure></p>
<p>Chemists routinely evaluate changes in the enthalpy of chemical systems as the reactants are converted into products. The heat absorbed or released by a reaction at constant pressure is the same as the change in enthalpy and is identified by the symbol ΔH.</p>
</sec>
<sec id="j_rmzmag-2021-0012_s_003">
<div>Discussion of results</div>
<p>Using the LINSEIS ‘PT STA 1600’ to analyse the Fe-Ni alloy, we have determined the enthalpy, which decreases as the temperature rises (ΔH&lt;0), leading to the conclusion that these reactions are exothermic [<a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_003">3</a>, <a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_004">4</a>]. Energy must be inserted into the system to break the chemical bonds, as they frequently do not break away spontaneously. The formation of bonds includes the release of energy; therefore, if more energy is produced in the formation of the bond than is necessary to break the bond, the enthalpy is negative—as we have found in the Fe-Ni alloy [<a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_003">3</a>]. In this example, the change in enthalpy is negative because heat is released from the system, causing the overall enthalpy of the system to decrease [<a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_003">3</a>, <a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_004">4</a>].</p>
<p>The heat of the reaction is the change of enthalpy for a chemical reaction [<a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_003">3</a>]. The determination of the enthalpy of the Fe-Ni alloy supports our conclusion that the Fe-Ni alloy is an appropriate product for the acquisition of special steels and other stable alloys [<a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_003">3</a>, <a ref-type="bibr" href="#j_rmzmag-2021-0012_ref_004">4</a>].</p>
</sec>
</div>

Determining the Enthalpy of an Fe-Ni Alloy at Various Temperatures Using the ‘STA’ PT 1600 Equipment

Materials and Geoenvironment

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Določanje entalpije pri različnih temperaturah za zlitino Fe-Ni z napravo ‘STA’ PT 1600

In this research paper we have determined the enthalpy of the Fe-Ni alloy using the ‘STA’ equipment at the laboratory of the University of Mitrovica “Isa...

Determining the Enthalpy of an Fe-Ni Alloy at Various Temperatures Using the ‘STA’ PT 1600 Equipment

Article Category: Original Scientific Article

Pubblicato online: 04 set 2023

Pagine: 51 - 55

Ricevuto: 07 gen 2021

Accettato: 12 giu 2021

DOI: https://doi.org/10.2478/rmzmag-2021-0012

Parole chiave
STA, alloy, Fe-Ni, enthalpy, exothermic process

© 2021 Zarife Bajraktari-Gashi et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Determining the Enthalpy of an Fe-Ni Alloy at Various Temperatures Using the ‘STA’ PT 1600 Equipment

Article Category: Original Scientific Article

Pubblicato online: 04 set 2023

Pagine: 51 - 55

Ricevuto: 07 gen 2021

Accettato: 12 giu 2021

DOI: https://doi.org/10.2478/rmzmag-2021-0012

Parole chiaveSTA, alloy, Fe-Ni, enthalpy, exothermic process

© 2021 Zarife Bajraktari-Gashi et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Parole chiave
STA, alloy, Fe-Ni, enthalpy, exothermic process