ПЕРСПЕКТИВЫ ПИРОМЕТАЛЛУРГИЧЕСКОЙ ПЕРЕРАБОТКИ ТЕХНОГЕННЫХ ОТХОДОВ АЛЮМИНИЕВОГО ПРОИЗВОДСТВА

The waste recycling problem of aluminum production is discussed. The effect of cathode lining fluorocarbons on the environment is estimated. A short review of the practices concerning waste processing of aluminum production is given. The opportunities to organize nonwaste technology at aluminum plants are considered. The results of laboratory tests of waste samples of used potlining are presented.Обсуждается проблема утилизации отходов алюминиевого производства. Дана оценка воздействия фторуглеродов катодной футеровки на окружающую среду. Представлен краткий обзор практик переработки отходов производства алюминия. Рассмотрены возможности организации безотходных технологий на алюминиевых заводах. Приведены результаты лабораторных исследований образцов отходов отработанной футеровки

Impact of a Bacillus Direct-Fed Microbial on Growth Performance, Intestinal Barrier Integrity, Necrotic Enteritis Lesions, and Ileal Microbiota in Broiler Chickens Using a Laboratory Challenge Model

Decreases in the use of antibiotics and anticoccidials in the poultry industry have risen the appearance of necrotic enteritis (NE). The purpose of this study was to evaluate the effect of a Bacillus direct-fed microbial (DFM) on growth performance, intestinal integrity, NE lesions and ileal microbiota using a previously established NE-challenged model. At day-of-hatch, chicks were randomly assigned to three different groups: Negative control (NC), Positive control (PC) challenged with Salmonella Typhimurium (day 1), Eimeria maxima (EM, day 13) and Clostridium perfringens (CP, day 18–19), and Bacillus-DFM group (DFM) challenged as the PC. Body weight (BW) and body weight gain (BWG) were measured weekly. Total feed intake (FI) and feed conversion ratio (FCR) were evaluated at day 21. Liver samples were collected to assess bacterial translocation and blood samples were used to measure superoxide dismutase (SOD) and fluorescein isothiocyanate-dextran (FITC-d). Intestinal contents were obtained for determination of total IgA and microbiota analysis. NE lesion scores (LS) were performed at day 21. Chickens consuming the DFM significantly improved BW and had a numerically more efficient FCR compared to PC at day 21. Additionally, there were no significant differences in FCR between the DFM group and NC. Furthermore, the DFM group showed significant reductions in LS, IgA and FITC-d levels compared to the PC. However, there were no significant differences in SOD between the groups. The microbiota analysis indicated that the phylum Proteobacteria was significantly reduced in the DFM group in comparison to PC. At the genus level, Clostridium, Turicibacter, Enterococcus, and Streptococcus were reduced, whereas, Lactobacillus and Bacillus were increased in the DFM group as compared to PC (p < 0.05). Likewise, the DFM significantly reduced CP as compared to PC. In contrary, no significant differences were observed in bacterial composition between NC vs. DFM. In addition, beta diversity showed significant differences in the microbial community structure between NC vs. PC, and PC vs. DFM. These results suggest that the dietary inclusion of a selected DFM could mitigate the complex negative impacts caused by NE possibly through mechanism(s) that might involve modulation of the gut microbiota

Получение полых полуфабрикатов изделий из медных сплавов электротехнического назначения способом винтовой прокатки

The article proposes a process for obtaining semi-finished products in the form of pipes made of copper alloys for electrical applications using the screw rolling method. The paper presents the results of experimental piercing and rolling of pipe samples made of Cu–0.75Cr copper alloy billets with a diameter of 45 mm. The 43.5×10.0 mm samples obtained after piercing using a two-roll screw rolling mill had exact geometrical dimensions: outer diameter deviation at the front end was up to 1 %, at the back end – up to 2.4 %; relative variation in wall thickness at the front end was 0.3÷0.5 %, at the rear end – 0.5÷1.0 %. Then pierced pipe samples were rolled using a three-roll radial-shear rolling (RSR) mini mill with a different total degree of reduction – samples were obtained with an outer diameter of 30, 25 and 18 mm. The reduction process was analyzed from the point of view of internal hole stability and deformation. In case of 30 % relative reduction of the outer diameter, rolling without a mandrel is accompanied by wall thickening. In this case, inner diameter deviations are within acceptable limits. The experiments on obtaining samples from the Cu–0.75Cr alloy by screw piercing and reduction in the RSR mill show that this scheme can be implemented in principle in industry. At the same time it is necessary to define more exactly deformation parameters (degree of deformation, choice of reduction scheme) to obtain a quality product. Various options for heat treatment (HT) of the obtained pipe samples and the effect of the HT method on electrical conductivity and hardness are considered. Samples after piercing had a conductivity of 59.3 % IACS. The maximum electrical conductivity of 76.7 % IACS was obtained on samples after quenching from a temperature of 1020 °C and aging at 450 °C for 3 h. The results of the work show the fundamental possibility of obtaining semi-finished products from copper alloys for electrical purposes using the screw rolling method.Предложен способ получения полуфабрикатов в виде труб из медных сплавов электротехнического назначения методом винтовой прокатки. Представлены результаты экспериментальной прошивки и прокатки образцов труб из заготовок медного сплава Cu–0,75Cr диаметром 45 мм. Полученные образцы размером 43,5×10,0 мм после прошивки в двухвалковом стане винтовой прокатки имели точные геометрические размеры: отклонение по наружному диаметру на переднем конце – до 1 %, на заднем конце – до 2,4 %, относительная поперечная разностенность на переднем конце составила 0,3÷0,5 %, на заднем конце – 0,5÷1,0 %. Далее прошитые образцы труб были прокатаны на трехвалковом министане радиально-сдвиговой прокатки (РСП) с разной суммарной степенью обжатия – получены образцы с наружным диаметром 30, 25 и 18 мм. Процесс редуцирования проанализирован с точки зрения стабильности и формоизменения внутреннего отверстия. При относительном обжатии наружного диаметра на 30 % прокатка без оправки сопровождается увеличением толщины стенки. При этом отклонения внутреннего диаметра находятся в допустимых пределах. Проведенные эксперименты по получению образцов из сплава Cu–0,75Cr способом винтовой прошивки и редуцирования в стане РСП показывают, что данная схема может быть принципиально реализована в промышленности. В то же время для получения качественного продукта необходимо уточнение параметров деформации (степени деформации, выбора схемы редуцирования). Рассмотрены различные варианты термообработки (ТО) полученных образцов труб и влияние способа ТО на электропроводность и твердость. Образцы после прошивки имели электропроводность 59,3 % IACS. Максимальная электропроводность 76,7 % IACS получена на образцах после закалки с температуры 1020 °С и старения при 450 °С в течение 3 ч. Результаты работы показывают принципиальную возможность получения полуфабрикатов изделий из медных сплавов электротехнического назначения способом винтовой прокатки