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Chalcopyrite leaching by amino acid solutions in the presence of hydrogen peroxide

Nurtazina Nargiza, Uvarov Nikolai, Azhigulova Ryskul, Tyapkin Pavel

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 157067

EN

It is demonstrated that amino acids such as glycine, betaine, and lysine may be applied as selective copper leaching agents in the process of hydrochemical oxidation of chalcopyrite at atmospheric pressure and in the temperature range 25÷65 °C. The advantage of the proposed method is its relative environmental friendliness. Solid samples of the initial mineral and leached chalcopyrite residues were analyzed by X-ray diffraction analysis, and Mössbauer and Raman spectroscopy. The results of the atomic absorption analysis showed that copper's extraction efficiency increased when the experiment's duration was raised and when the process temperature was higher. The leaching ability of amino acids was evaluated by the specific leaching rate of chalcopyrite in these reagents. Amino acid leaching was thought to be mainly due to the complexation of copper (II) glycinates, copper (II) betainates and copper (II) lysinates. This reaction can be enhanced by adding hydrogen peroxide to the system as an oxidant. It was determined that glycine was more effective as a leaching agent than betaine and lysine. Based on experimental data, it was assumed that the most possible mechanism is selective copper leaching due to the formation of chalcopyrite-based solid solution Cu1-XFeS2.

2

Processing conditions for micronization of peas (Pisum sativum) and an in-vitro evaluation of the product

Arntfield S.D., Zhang M.Z., Nyachoti C.M., Guenter W., Cenkowski S.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2004

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nr 7

27-38

EN

Tempering and storage conditions were investigated for the processing of peas using infrared heat (micronization). The criteria for evaluation of processing conditions included the extent to which starch was gelatinized, the extract viscosity of the peas and the availability of lysine in the peas. In the initial study using the pea (Pisum sativum) cultivar Croma, a tempering level of 24% moisture was selected for the micronization treatment as it resulted in significant increases (pŁ0.05) in starch gelatinization, while maintaining available lysine levels and reducing extract viscosity. With minor exceptions, which included a decrease in available lysine for the cultivar Carneval, similar results were obtained when these conditions were applied to four other pea cultivars (two yellow and two green) in a second study. Storage at room temperature (22oC) was able to preserve these characteristics, and there was no benefit to storing at a lower temperature of 4oC for up to 6 weeks. Differences in available lysine for the yellow Carneval and unknown cultivars, seen immediately after processing, were not a factor following storage. The production of micronized peas suitable for incorporation into animal feed is possible if the appropriate moisture content during tempering is selected.

PL

Badano wpływ nawilżania oraz warunków przechowywania grochu, który został poddany obróbce cieplnej w zakresie promieniowania podczerwonego (mikronizacji). Kryteria do oceny warunków przetwarzania obejmowały ilość skleikowanego krochmalu, lepkość ekstraktu z grochu oraz dostępność (dyspozycyjność) lizyny w grochu. W początkowych badaniach, używając grochu (Pisum sativum) odmiany Croma, wybrano poziom nawilżenia 24%, ponieważ wynikiem tego był znaczny (pŁ0.05) wzrost skleikowania krochmalu przy jednoczesnym utrzymaniu dyspozycyjności poziomu lizyny i obniżonej lepkości ekstraktu z grochu. Podobne rezultaty otrzymano, gdy takie same warunki przetwarzania były zastosowane w drugiej części eksperymentów dla czterech innych odmian grochu (dwie żółte odmiany i dwie zielone), z małym jednak wyjątkiem, gdy zanotowano obniżenie lizyny w odmianie Carneval. Przechowywanie grochu po mikronizacji w pokojowej temperaturze (22oC) zachowało otrzymane charakterystyki materiału, nie dając żadnych różnic w mierzonych właściwościach podczas przechowywania grochu w temperaturze 4oC przez 6 tygodni. Różnice w dostępności lizyny w żółtej odmianie Carneval i nieznanych odmianach, a oceniane zaraz po mikronizacji, zatarły się po kilkutygodniowym okresie przechowywania. Wyniki badań potwierdzają, że groch poddany mikronizacji może być użyty z powodzeniem w celach paszowych, jeżeli zostanie on nawilżony do właściwego poziomu przed mikronizacją.

3

Niskocząsteczkowe inhibitory plazminy

Midura-Nowaczek K.

Wiadomości Chemiczne

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1998

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[Z] 52, 11-12

871--887

EN

Plasmin, serine protease with trypsin specifity, plays a key role in the process of fibrinolysis. Analogs of lysine like e-aminocaproic acid and trans-4-aminomethylclohexanecarboxylic acid are employed clinically as plasmin inhibitors and exhibit an inhibitory effect by blocking lysine binding sites of the enzyme. Their inhibitory activity on plasmin with the respect to fibrinogen and other proteins is much weaker than towards fibrin. Because of this reason investigations on the synthesis of an active centre directed inhibitors of plasmin were also undertaken. A great number of compounds was obtained including derivatives of w-aminoacids or lysine. Next important group were short peptides with C-terminal lysine or arginine derivatives such as aldehydes, chloromethylketones, fluoromethylketone, methylketones, amides or esters. This paper presents literature data on structure-activity relationship for low molecular inhibitors of plasmin with a structure of aminoacids or peptides derivatives.