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1

Leaching behaviour of limonite ores from Lapaopao, Southeast Sulawesi, Indonesia : Effect of mineralogy and acid types

Onggang Suharto, Maulana Adi, Sufriadin, Irfan Ulva Ria

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 3

art. no. 189217

EN

An atmospheric leaching study of limonite ores from Lapaopao, Southeast Sulawesi, using hydrochloric acid (HCl), nitric acid (HNO3), and sulfuric acid (H2SO4) has been performed. The objectives of this study were to analyze the effect of ore mineralogy and acid types on the dissolution behavior of minerals and the leaching rate of Ni and Co at atmospheric pressure conditions. Mineralogical analysis was carried out using optical microscopy, scanning electron microscopy (SEM), and X-ray diffractometry (XRD), while the ore's chemical composition was determined by using X-ray fluorescence spectrometry (XRF) and atomic absorption spectrophotometry (AAS). Mineralogically, the limonite ores are dominated by goethite, followed by gibbsite, talc, and lizardite, with less amounts of hematite and quartz. Analysis results of solid residues revealed that mineral dissolution order was determined as follows: goethite > lizardite > gibbsite> hematite > talc> quartz. The results of the leaching experiment exhibited that the order of leaching rates of Ni in the three ores samples using three different acids were found as follows: Ore-1 > Ore-2 > Ore-3. Comparison of HCl, HNO3, and H2SO4 as the lixiviants for the leaching of limonite ores demonstrated that HCl was the most reactive acid, followed by HNO3 and then H2SO4. This might be due to the differences in mineralogical nature and reactivities of acids during the leaching process.

2

Improving Wear Resistance of Mechanical Seal Using NI-P Electroless Coating

Jasim Hussein Hatem, Mughir Walaa Amer, AbidAli Abdulraheem

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no. 8

375--384

EN

Electroless nickel phosphor coating is an important technology in the field of industrial coatings which is widely used in many technical applications. The electroless nickel phosphorus layer has high hardness and corrosion resistance, making it ideal for multiple applications for example, automotive, aerospace and electronics industries. Sulfuric acid is an essential agent in many industrial processes. The corrosive and abrasive nature of sulfuric acid results in rapid wear of mechanical parts, resulting in frequent replacement, increased maintenance costs, and may cause environmental and safety issues. This work employed electroless Ni-P coating, which was effectively assigned to mechanical seal models. The Taguchi design array L9 was used to conduct the experimental work. Mechanical properties such as Vickers hardness and wear rate were measured at different heat treatment temperature, coating time and coating bath temperature. The coating thickness was measured using an optical microscope. The results showed that the hardness increased reaching peak as 653 HV at 400C° and coating time 4 hours. As for wear resistance, it was recorded the lowest value as 0.00060 under same conditions. Through SEM and XRD, the formation of NiP and Ni3P were found. ANOVA demonstrated that heat treatment temperature was the most effected factor that contributed to enhance both hardness and wear resistance, followed by coating time.

3

Study on the mechanism and kinetics of sulfuric acid leaching scandium from rich scandium anatase

He Fei, Gao Likun, Chen Long, Rao Bing, Shen Hairong, Peng Kebo, Gao Guangyan

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 3

art. no. 146171

EN

Scandium and its compounds have excellent properties, and are widely used in cutting-edge fields such as optics, electronics, and alloys. Thus, scandium is an important strategic metal. However, scandium is extremely sparsely distributed in the earth's crust, rarely occurs as an independent mineral, and requires a complex recovery process. Therefore, the study of the extraction of scandium is of great practical significance. This study examined the leaching test and kinetics of scandium under the acid leaching system of refractory anatase ore. Under appropriate two-stage countercurrent leaching conditions, the first stage of the particle size of fraction of -0.074 mm 82.6%, initial H2SO4 concentration of 6 mol/L, leaching temperature of 100 °C, acid/solid ratio of 3 ml/g, stirring speed of 300 rpm, and leaching time of 50 min; and the second stage of the initial H2SO4 concentration of 11 mol/L, leaching temperature of 150 °C, acid/solid ratio of 4 ml/g, stirring speed of 300 rpm, and leaching time of 50 min, a scandium leaching rate of 96.98% was achieved. The kinetics of scandium leaching conformed to a shrinking-core model, and sulfuric acid concentration and temperature were the most important parameters affecting the scandium leaching rate. The kinetic analysis of scandium leaching at different sulfuric acid concentrations showed that as the concentration increased, the sulfuric acid leaching of scandium changed from being chemical reaction-controlled to internal diffusion-controlled, and the apparent reaction order was 1.2429. The kinetics of scandium leaching at different temperatures showed that the sulfuric acid leaching of scandium was reaction-controlled and the apparent activation energy was 42.21 kJ-mol-1.

4

Evaluation of the corrosion resistance of spark plasma sintered stainless steel 316L matrix composites with zirconium diboride in sulfuric acid

Stępień Michał, Sulima Iwona, Hyjek Paweł, Kowalik Remigiusz

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 3

art. no. e127

EN

The infuence of the zirconium diboride content and the method of initial material preparation on the corrosion properties of the composite on the 316L stainless steel matrix were determined. The powders were prepared in a Turbula mixer and a planetary mill. The corrosion properties were estimated on the basis of electrochemical tests, including open-circuit potential measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy. The presence of the ceramic phase changes the corrosion resistance of the tested materials due to porosity, which afects the corrosion mechanism. The standard potentiodynamic tests do not reveal poor corrosion resistance of porous materials, and only 24 h tests reveal accurate corrosion resistance of composite materials. Composites cannot go into a stable passive state because of the penetration of electrolytes into the pores and tend to oxidize systematically. 24-h corrosion tests indicate that samples prepared in a planetary mill show better corrosion resistance than those prepared in a Turbula mixer.

5

Heat effects in the reaction of sulfuric acid with ilmenites influenced by initial temperature and acid concentration

Jabłoński Maciej, Lubkowski Krzysztof, Tylutka Sandra, Ściążko Andrzej

Polish Journal of Chemical Technology

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2021

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Vol. 23, nr 3

37--42

EN

The influence of temperature and sulfuric acid concentration on the enthalpy and the rate of heat release during the reaction of Norwegian and Australian ilmenites with sulfuric acid was determined. The experimental results obtained from calorimetric measurements were compared with theoretical calculations based on the oxide composition and the phase composition of the raw material. Experimentally determined heat of reaction for Norwegian ilmenite (900–940 kJ/kg) and Australian ilmenite (800–840 kJ/kg) showed good agreement with theoretical calculations based on the phase composition of the raw material. It was found that the enthalpy of ilmenites decomposition reaction does not depend on the concentration of sulfuric acid in the concentration range from 83% to 93%. It was also demonstrated that the temperature and concentration of sulfuric acid have a significant impact on the thermokinetics of the decomposition process, increasing the value of the average rate of temperature change.

6

Jiroft refractory manganese ore leaching using oxalic acid as reducing agent in sulfuric acid solution

Sobouti Arash, Shafaat Niosha, Abdollahzadeh Ali A.

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 2

374--385

EN

Leaching process of Jiroft refractory manganese ore was investigated. The effects of operating parameters such as liquid to solid ratio, pulp temperature, sulfuric acid concentration, and oxalic acid concentration were studied and the optimization was done through the response surface methodology (RSM) based on central composite design (CCD) model. The recoveries of Mn, Fe and Si were selected as response of design. The optimum condition was determined by ANOVA, indicating that the liquid to solid ratio, oxalic acid concentration and pulp temperature for Mn recovery and liquid to solid ratio, pulp temperature and sulfuric acid concentration for Fe recovery and liquid to solid ratio for Si recovery were the most effective parameters, respectively. Under the optimum conditions of liquid to solid ratio= 11.8%, pulp temperature= 70 ℃ sulfuric acid concentration= 40 g/L and oxalic acid concentration= 35 g/L, 71.1%, 4.67% and 0.6% of Mn, Fe and Si were recovered, respectively.

7

Modyfikacja procedury ekstrakcji frakcji torakalnej kwasu siarkowego(VI) z filtrów w metodzie oznaczania tego kwasu w powietrzu na stanowiskach pracy

Szewczyńska M.

Podstawy i Metody Oceny Środowiska Pracy

|

2017

|

Nr 2 (92)

5--19

PL

Kwas siarkowy ma wszechstronne zastosowanie w wielu gałęziach przemysłu, co powoduje narażenie dużej grupy pracowników na tę szkodliwą dla zdrowia substancję. W 2012 r. ustalono nową wartość najwyższego dopuszczalnego stężenia dla frakcji torakalnej kwasu siarkowego(VI) na poziomie 0,05 mg/m3. W związku ze zmianą kryterium oceny narażenia zawodowego na ten kwas opracowano metodę umożliwiającą oznaczanie frakcji torakalnej, zgodnie z zaleceniami zawartymi w normie PN EN-481, której stosowanie w warunkach rzeczywistych wykazało konieczność modyfikacji etapu ekstrakcji z filtrów metylocelulozowych. Celem pracy była modyfikacja metody ekstrakcji kwasu siarkowego(VI) z filtrów i jej walidacja. W pracy zastosowano metodę oznaczania kwasu siarkowego(VI) z wykorzystaniem chromatografii jonowej z detekcją konduktometryczną. Do badań zastosowano kolumnę analityczną dionex ionpac® AS22 (4 x 250 mm) z przedkolumną dionex ionpac AG22 (4 x 50 mm) oraz mieszaninę węglanu i wodorowęglanu sodu, będącą fazą nośną o elucji izokratycznej i przepływie 1,2 ml/min. Zaproponowane warunki rozdziału chromatograficznego umożliwiły oznaczenie jonów kwasu siarkowego(VI) w obecności jonów: fluorkowych, octanowych, chlorkowych, bromkowych, azotanowych, azotynowych i fosforanowych. Do pobierania próbek powietrza zastosowano próbnik parallel particle impactors (PPI) z filtrem metylocelulozowym dedykowanym dla frakcji torakalnej. Oznaczalność metody uzyskano na poziomie 2,125 µg/m3 przy pobieraniu 480 m3 powietrza i wymywaniu kwasu z filtra MCE wodą (10 ml). Granica wykrywalności, obliczona na podstawie stosunku sygnału do szumu wynosi 1,9 ng, a granica oznaczalności – 5,7 ng. Niepewność całkowita metody wynosi 11%, a niepewność rozszerzona – 23%. Dedykowane do pobierania frakcji torakalnej próbniki typu PPI zostały sprawdzone w warunkach rzeczywistych w zakładach produkujących i przetwarzających kwas siarkowy. Zmodyfikowano opublikowaną w kwartalniku „Podstawy i Metody Oceny Środowiska Pracy” metodę próżniowej filtracji w celu wymywania siarczanów z filtrów MCE. Zastosowanie wytrząsania mechanicznego filtrów MCE wodą ultraczystą milli-q przez 30 min pozwoliło na uzyskanie około 100-procentowego odzysku kwasu siarkowego z analizowanych filtrów z jednoczesnym uniknięciem wymywania interferentów. Uzyskane wyniki potwierdziły obecności kwasu siarkowego(VI) we frakcji torakalnej badanych aerozoli o stężeniach w zakresie 0,03 ÷ 1, 47 wartości najwyższego dopuszczalnego stężenia (NDS).

EN

Sulfuic acid is widely used in many industries, which is associated with the exposure of a large group of employees to this harmful substance. In 2012, a new value of occupational exposure limit for sulfuric acid as the thoracic fraction was introduced in Poland. Due to this change, the method enabling determination of sulfuric acid in the thoracic fraction has been established in accordance with the requirements of the Standard No. EN 481. The practical use of this method indicated the necessity of modificating the procedure for sulfuric acid extraction from methylcellulose filters. The aim of this study was to modify the extraction method of sulfuric acid(VI) and to validate the ion chromatography method. The determination of sulfuric acid(VI) with ion chromatography with conductivity detection was applied in this study. The study used an analytical column IonPac® Dionex AS22 (4 × 250 mm) with a precolumn Dionex IonPac AG22 (4 × 50mm) and a mixture of carbonate and bicarbonate, as a carrier phase of an isocratic flow rate 1.2 ml/min. The proposed conditions for the chromatographic separation of ions enabled the determination of sulfuric acid (VI) in the presence of fluoride ions, acetate, chloride, bromide, nitrate, nitrite and phosphate. Parallel Particle Impactors (PPI) with mixed cellulose filter dedicated for thoracic fraction was used for sampling. The determination method was achieved at 2.125 µg/m3 for 480 m3 of air and extraction of MCE filter with water (10 ml). The detection limit calculated on the basis of the signal-to-noise ratio was 1.9 ng, and the limit of quantification was 5.7 ng. The uncertainty of the overall method is 11% and 23% of expanded uncertainty. PPI sampler dedicated to collect thoracic fractions has been tested in real conditions in factories producing and processing sulfuric acid. The method of vacuum filtration for sulfates extraction from filters MCE, which was published in The Principles and “Methods of Assessing the Working Environment” (PiMOŚP), was modified. The use of a mechanical shaking MCE filter with ultrapure water Milli-Q for 30 min enabled to receive approximately 100% recovery of sulfuric acid from the filter analyzed while avoiding the leaching of interferents. The results confirmed the presence of sulfuric acid(VI) in the thoracic fraction of aerosol tested at concentrations ranging from 0.03 to 1.47 MAC value.

8

Oxidative pressurized acid leaching of waste printed circuit boards

Lundstrom M., Seisko S., Jascisak J., Orac D., Aromaa J., Havlik T., Forsen O.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 2

781--792

EN

The amount of waste printed circuit board (WPCB) increases continuously. There is an economic and environmental need to recover valuable metals from WPCBs. In this study, the applicability of oxidative pressurized acid leaching of WPCBs rich in copper and tin was investigated. The effect of leaching parameters such as temperature, partial oxygen pressure and chloride concentration on metal dissolution from WPCBs was studied in sulfuric acid media. It was shown that non-metallic elements present in WPCBs initiated gas formation, namely CO2 and CO, during oxidized pressure acid leach. Decomposition of plastic components already started at 90 °C with 1.5 MPa oxygen overpressure in the presence of 1 g/dm3 chlorides. Gas formation was shown to have a negative impact on the process since copper extraction was reduced to 27% compared to 80-90% extraction achieved from anode slimes used as a reference material. It was suggested that gas formation related to plastic components could have a severe impact on metal yields. The highest dissolution of tin equal to 36% was achieved at room temperature. It was found that higher temperature promoted tin hydrolysis.

9

Zagrożenia podczas magazynowania kwasu siarkowego w Grupa Azoty Zakłady Chemiczne „Police” S.A.

Ubowska A., Kotrys M.

Prace Naukowe Akademii im. Jana Długosza w Częstochowie. Technika, Informatyka, Inżynieria Bezpieczeństwa

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2016

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T. 4

477--489

PL

Najczęstszym źródłem awarii przemysłowych są zbiorniki magazynowe niebezpiecznych substancji chemicznych. Substancją taką jest produkowany przez Grupa Azoty Zakłady Chemiczne „Police” S.A. kwas siarkowy. Z uwagi na niebezpieczne właściwości kwasu, istotna jest ocena zagrożeń, jakie niesie za sobą jego magazynowanie. Czy potencjalny wyciek składowanego na terenie zakładu kwasu może mieć wymierne skutki dla otoczenia? Czy środki zaradcze stosowane w zakładach przemysłowych są wystarczające, aby zapobiec skażeniu środowiska, a przede wszystkim zabezpieczyć pracujących w pobliżu pracowników? Aby odpowiedzieć na te pytania, przeprowadzono komputerową symulację rozprzestrzeniania się mgieł kwasu siarkowego w powietrzu dla różnych scenariuszy awarii, skutkujących wyciekami kwasu ze zbiorników magazynowych na terenie Grupa Azoty Zakłady Chemiczne „Police” S.A., z wykorzystaniem programu ALOHA.

EN

The most common cause of industrial accidents is the malfunction of storage tanks for hazardous chemicals. Such a substance, namely sulphuric acid is produced by Grupa Azoty Zakłady Chemiczne „Police” S.A.. Due to hazardous properties of the acid, it is important to assess the risks that entail its storage. Can potential leakage of acid stored in the industrial plants have measurable effects on the environment? Are remedies used in industrial plants sufficient to prevent contamination of the environment and, above all, are they adequate to secure the employees working in the vicinity? To answer these questions, we conducted a computer simulation of the spread of the mists of sulfuric acid in the air for various scenarios of accidents that result in the leakage of the storage tanks in the Grupa Azoty Zakłady Chemiczne „Police” S.A., using the ALOHA program.

10

Badanie zawartości frakcji torakalnej i wdychalnej kwasu siarkowego(VI) w różnych procesach technologicznych

Szewczyńska M., Pośniak M.

Przemysł Chemiczny

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2015

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T. 94, nr 10

1872-1876

PL

Przedstawiono wybrane etapy produkcji i przetwarzania kwasu siarkowego(VI), które stanowią jedno z przykładowych źródeł emisji aerozolu kwasu w środowisku pracy. Przedstawiono odpowiednie próbniki do pobierania frakcji aerozolu. Porównano wyniki badań kwasu siarkowego we frakcjach torakalnej i wdychalnej.

EN

The air samples collected at various stages of concd. H2SO4 and TiO2 prodn. were studied for the acid content. The highest concs. of the acid in the thoracic fraction were found at the point of sampling a mixt. contg. 30% H2SO4, at the emitter as well as at the clarifier. They were 10.32, 10.92 and 35.5 µg/m3, resp. The concns. of the inhalable fraction taken at the same points were 28.42, 16.55 and 85.8 µg/m3, resp. Thoracic fractions of H2SO4 constituted 26–95% of inhalable fraction, depending on the type of sampling and analyzed process.

11

Chemical treatment of kaolin. Case study of kaolin from the Tamazert– Jijel mine

Chouafa M., Idres A., Bouhedja A., Talhi K.

Mining Science

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2015

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Vol. 22

171--180

EN

The Tamazert-Jijel kaolin deposit is located in eastern Algeria, It was formed during a process of hydro-thermal alteration of feldspars rich in potassium. Kaolin, obtained at the mine, mainly contains varying amounts of impurities such as iron oxide (Fe2O3) and anatase (TiO2). These components negatively affect the quality of the commercial product. This research was performed to improve the quality of kaolin to be used in the paper industry with the goal of reducing the impurities of iron and titanium oxides. Different sized fractions of the original sample were analyzed by XRD. The results obtained showed that the mineralogical composition is: quartz, muscovite, kaolinite, dolomite, albite and orthoclase. Kaolin, like all clays, has a thin dissemination of minerals throughout it. After processing kaolin, the particle size fraction of less than 45μm, corresponding to the liberation mesh size, was retained for purification by chemical treatment with different acids of different concentrations (hydrochloric acid, sulfuric acid, acetic acid), heated to boiling point temperatures. The kaolin samples treated with the various acids above were analyzed by X-ray fluorescence and by XRD. The results obtained from the sample treated with hydrochloric acid show that the iron oxide content of acid is reduced by 1.65% to 0.88%. Meanwhile, the brightness of the sample reached 90% under the effect of the treatment with hydrochloric acid at concentration of 2 mole/dm3.

12

Optimising sulfuric acid hard coat anodising for an Al-Mg-Si wrought aluminium alloy

Bartolo N, Sinagra E, Mallia B

Materials Science Poland

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2014

|

Vol. 32, No. 2

136--144

EN

This research evaluates the effects of sulfuric acid hard coat anodising parameters, such as acid concentration, electrolyte temperature, current density and time, on the hardness and thickness of the resultant anodised layers. A small scale anodising facility was designed and set up to enable experimental investigation of the anodising parameters. An experimental design using the Taguchi method to optimise the parameters within an established operating window was performed. Qualitative and quantitative methods of characterisation of the resultant anodised layers were carried out. The anodised layer’s thickness, and morphology were determined using a light optical microscope (LOM) and field emission gun scanning electron microscope (FEG-SEM). Hardness measurements were carried out using a nano hardness tester. Correlations between the various anodising parameters and their effect on the hardness and thickness of the anodised layers were established. Careful evaluation of these effects enabled optimum parameters to be determined using the Taguchi method, which were verified experimentally. Anodised layers having hardness varying between 2.4 – 5.2 GPa and a thickness of between 20 – 80 μm were produced. The Taguchi method was shown to be applicable to anodising. This finding could facilitate on-going and future research and development of anodising, which is attracting remarkable academic and industrial interest.

13

Aspekty ekologiczne i strategia rozwoju przemysłu kwasu siarkowego

Grzesiak P., Grobela M., Motała R.

Przemysł Chemiczny

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2013

|

T. 92, nr 9

1759-1764

PL

Omówiono ekologiczne aspekty produkcji kwasu siarkowego w Hucie Miedzi Głogów na poszczególnych etapach przebiegu procesu. Przedstawiono wyniki optymalizacji parametrów pracy instalacji w całym cyklu produkcyjnym, pozwalającej stabilizować emisję związków siarki. Omówiono strategię rozwoju produkcji kwasu siarkowego w przemyśle hutniczym.

EN

An industrial plant for prodn. of H2SO4 in a Polish copper smelter and refinery was analyzed from ecolog. and economic points of view. In particular, the process optimization, the oxidn. catalyst improvement and new uses for the SO2 were taken into consideration.

14

Optimization of rapeseed oil fatty acid esterification with methanol in the presence of sulfuric acid

Brinks J., Malins K., Kampars V., Prilucka J., Apseniece L.

Polish Journal of Chemical Technology

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2013

|

Vol. 15, nr 4

54-59

EN

The interest in biodiesel production from low cost feedstocks is still increasing. Such feedstocks usually contain large amounts of free fatty acids, which make the currently employed base catalysts inefficient, thereby promoting the use of acid catalysts. Due to the high activity and low cost, sulfuric acid could become the most widely used acid catalyst for biodiesel production. Research undertaken so far using sulfuric acid for esterifi cation of fatty acids has shown that the products obtained fail to meet the requirements of the standard EN 14214. This paper describes a systematic study of rapeseed oil fatty acids esterification in order to obtain a product complying with the standard EN 14214. The influence of sulfuric acid concentrations (0.1-3.0%), methanol molar ratios (1:1-20:1) and reaction time (0-360 min) was evaluated. Finally, a two-stage esterification process was developed, where in optimal conditions esterification yield of 97.8% and ester content of 99.6% were achieved.

15

Synteza glutaranu dicykloheksylowego w obecności kwasu siarkowego i bez dodatku katalizatora

Grzesik M., Skrzypek J., Witczak T., Kulawska M., Madej-Lachowska M.

Przemysł Chemiczny

|

2012

|

T. 91, nr 11

2225--2227

PL

Przedstawiono wyniki badań kinetycznych procesu estryfikacji kwasu glutarowego cykloheksanolem. Proces prowadzono w półciągłym reaktorze laboratoryjnym w warunkach izotermicznych. Wykazano, że w obecności kwasu siarkowego jako katalizatora, zarówno reakcja pierwsza (tworzenia monoestru) jak i reakcja druga (powstawania diestru) jest pierwszego rzędu względem odpowiednio kwasu i monoestru, Przy braku katalizatora zmianie uległa kinetyka reakcji pierwszej (reakcja drugiego rzędu względem kwasu), a równanie kinetyczne reakcji drugiej pozostało niezmienione. Wyznaczono wartości liczbowe stałych kinetycznych.

EN

Glutaric acid was esterified with cyclohexanol to resp. mono- and diesters in lab. semibatch reactor under isothermal conditions to study the reaction kinetics. In the presence of H₂SO₄ catalyst both reaction were on first order with respect to the acid and the second reaction was first order with respect to monoester. Without any catalyst, the kinetics of the first reaction has changed to the second order with respect to acid while the kinetics of the second reaction remained unchanged. The parameters of kinetic equations were detd.

16

Przemiany związków fosforu zawartych w fosforycie Maroko II w warunkach techniki PAPR z zastosowaniem mieszaniny kwasu siarkowego i fosforowego

Skut J., Hoffmann J., Hoffmann K.

Przemysł Chemiczny

|

2012

|

T. 91, nr 5

978-984

PL

Przedstawiono wyniki badań doświadczalnych procesu otrzymywania nawozów fosforowych PAPR (partially acidulated phosphate rock) z zastosowaniem mieszaniny kwasu siarkowego i fosforowego (PAPRKS KF) pod kątem przemian związków fosforu zawartych w fosforycie Maroko II. W przypadku wyników efektywności rozkładu na podstawie fosforu (P) rozpuszczalnego w wodzie (ERH₂O) stwierdzono zależność liniową dla produktów nawozowych PAPRKS KF o udziale H2SO4 w stopniu normy stechiometrycznej PAPR (ηPAPR) równym 80%. W miarę zmniejszania udziału H₂SO₄ w ηPAPR, następował wzrost nieliniowości trendu, dzięki czemu osiągano równocześnie wyższe wartości ηPAPR dla serii produktów PAPRKS KF o tej samej wartości ηPAPR. Stwierdzono bardziej efektywną konwersję fosforu pochodzącego z fluoroapatytu do rozpuszczalnego w wodzie Ca(H₂PO₄)₂ w konsekwencji wzrostu udziału procentowego H₃PO₄ w mieszaninie kwasów H₂SO₄ + H₃PO₄ w procesie zarabiania mlewa. Rezultaty efektywności rozkładu na podstawie fosforu rozpuszczalnego w obojętnym cytrynianie amonu (EROCA) charakteryzują się dla wszystkich serii próbek zależnością nieliniową, przy czym (szczególnie dla ηPAPR 0,1–0,5) osiągano wyższe wartości wraz ze wzrostem udziału H₃PO₄ w ηPAPR. Zaproponowano optymalny bilans materiałowy, wyrażony w postaci wykresu strumieniowego Sankeya dla otrzymywania produktu nawozowego PAPRKS KF o ηPAPR 0,3.

EN

Phosphate rock was decompd. with mixts. of H₂SO₄ and H₃PO₄ and studied for contens of citric acid, HCOOH, mineral acids, neutral NH₄ citrate and water-sol. P. The optimum fertilizer was produced at H₂SO₄/H₃PO₄ ratio 20:80 and contained mineral acid-sol. P₂O₅ at least 38% by mass, and H₂O-sol. P₂O₅ less than 1.5% by mass.

17

Kinetyka estryfikacji kwasów pimelinowego i suberynowego (korkowego) cykloheksanolem w obecności kwasu siarkowego jako katalizatora

Grzesik M., Skrzypek J., Ptaszek P., Kasprzyk-Mrzyk A.

Przemysł Chemiczny

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2012

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T. 91, nr 12

2425-2427

PL

Wykorzystując standardowy zestaw laboratoryjny (szklany półokresowy reaktor izotermiczny) wyznaczono krzywe kinetyczne dla syntezy pimelinianu i suberynianu dicykloheksylu. Stwierdzono, że w obecności kwasu siarkowego jako katalizatora, reakcja tworzenia monoestru jest reakcją pierwszego rzędu względem kwasu, a reakcja powstawania diestru jest pierwszego rzędu względem monoestru. Potwierdzono eksperymentalnie następczy przebieg obu reakcji. Określono parametry równań kinetycznych.

EN

Pimelic and subaric acids were esterified to the resp. diesters with cyclohexanol in presence of H₂SO₄ in a lab. isothermal semibatch reactor at 120–150°C (alc.-to-acid ratios 3:1 to 10:1) to study the reaction kinetics. The reaction had 2-step course. The formation of resp. monoesters was 1st order reaction with respect to the acid and the formation of diesters was 1st order reaction with respect to monoester. The activation energy of monoester formation was substantially higher than that of diester formation.

18

Estryfikacja kwasu glutarowego alkoholem 2-etyloheksylowym wobec kwasu siarkowego jako katalizatora i bez dodatku katalizatora

Grzesik M., Skrzypek J., Ptaszek P., Madej-Lachowska M.

Przemysł Chemiczny

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2012

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T. 91, nr 11

2228--2230

PL

Przedstawiono wyniki badań kinetycznych procesu estryfikacji kwasu glutarowego alkoholem 2-etyloheksylowym w izotermicznym, półciągłym reaktorze doświadczalnym. Stwierdzono, że w obecności kwasu siarkowego jako katalizatora, reakcja tworzenia monoestru jest reakcją drugiego rzędu względem kwasu i alkoholu, a reakcja tworzenia diestru jest pierwszego rzędu względem monoestru. Brak katalizatora powodował zmianę rzędu reakcji pierwszej (z rzędu pierwszego do rzędu drugiego względem kwasu). Potwierdzono szeregowy przebieg obu reakcji. Określono parametry równań kinetycznych.

EN

Glutaric acid was esterified with BuCHEtCH₂OH to resp. mono- and diesters in a lab. isothermal semibatch reactor to study the reaction kinetics. In the presence of H₂SO₄ catalyst, the reaction of monoester formation was 1st order reaction while the reaction of the diester formation was a 2nd order reaction. Lack of catalyst resulted in a change of the reaction order of monoester formation to the 1st order reaction with respect to acid. The parameters of kinetic equations were detd.

19

Extraction of vanadium and potassium compounds from the spent vanadium catalyst from the metallurgical plant

Mazurek K.

Polish Journal of Chemical Technology

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2012

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Vol. 14, nr 2

49-53

EN

A spent vanadium catalyst, from the plant of metallurgical type, was leached in a sulfuric acid solution to recover vanadium and potassium compounds. The effect of time, temperature, concentration of acid, catalyst particle size and phase ratio was studied. Additionally the concentration of iron, copper, zinc, arsenic and lead compounds was determined. The flow sheet for the proposed process of spent vanadium catalyst leaching is presented.

20

Wpływ składu fazy gazowej na właściwości katalizatora wanadowego stosowanego przy produkcji kwasu siarkowego

Grzesiak P., Grobela M., Motała R., Łukaszyk J.

Przemysł Chemiczny

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2011

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T. 90, nr 12

2193-2197