Using of aluminium slags and products of their pro‑cessing in metallurgical production

The work contains the results of the analysis of technical literature and author’s research on the use of aluminium slags and products of their processing in metallurgical production. It has been shown that the bulk of reagents derived from secondary aluminum production wastes (APWs) are used with increased sodium and potassium chloride. This creates some inconvenience for out‑of‑furnace steel treatment due to the increased chloride content in the working area. It is proposed for steel processing to use APWs formed during flux‑free melting or dump aluminium slags. This allows to reduce the content of salt fluxes residues to 1.0–1.5 % and to improve working conditions at ladle furnaces when liquefying refining slags.

Modern view on steel desulfurization

Modern technological schemes of steel production do not allow to achieve low (< 0.01 % S) and ultra-low (<0.005 % S) sulfur content on the production of in the metal directly. That is why out-of-furnace steel treatment is often used to remove sulfur. Desulfurization process of steel depends on the chemical composition of the slag, the time of its formation in the ladle, metal oxidation, conditions of mixing of steel in a ladle, additional technological operations and ladle metal processing. Methods are widely used for desulfurization of steel treatment of steel with solid slag-forming mixtures, synthetic slag, lime-aluminous slag, silico-calcium and other powdered materials. Modern approaches to the process of steel desulfurization in conditions steel production are analyzed in the Study. In particular, the Ukrainian (on the example of PJSC ‘Azovstal Iron & Steel Works’ and PJSC ‘Dneprovsky Integrated Iron & Steel Works named after Dzershinsky’) and foreign (on the example of PJSC ‘Severstal’ and PJSC ‘Magnitogorsk Iron & Steel Works’) experience of desulfurization under oxygen converter production. The use of technological complexes ‘Installation of pig iron desulfurization steel making unit’ and ‘Cast iron desulfurization installation steel making unit is ‘oven-bucket’ installation’ provides a deeper desulfurization of steel, the possibility of optimizing the cost of steel production, expands range of scarce products and eliminates a number of restrictive conditions that complicate current production. The analysis of steel C80D desulfurization process is given in the conditions of JSC ‘Moldova Steel Works’, in which partial sulfur removal occurs in an arc steel making furnace, and the ultra-low content is achieved by creating a highly basic refining slag in the process out-of-furnace processing of steel. The study of the kinetics of the desulfurization process of 20GL steel in the conditions of JSC ‘Tashkent Mechanical Plant’ with the use of solid slag-forming mixtures and modification of steel with rare-earth metals is analyzed. The issue of desulfurization of electric steel in the conditions of OJSC ‘Byelorussian Steel Works’ with injection of powdered materials through the installation ‘Velko’ during out-of-furnace processing of steel is considered. Keywords: steel desulfurization, desulfurizer reagent, degree of desulfurization, cast iron desulfurization installation, out-of-furnace processing of steel, ‘‘oven-bucket’’ installation.

Perancangan Sistem Kontrol Sinkronisasi Kecepatan Conveyor Feeding Dengan Kecepatan Calender Berbasis Inverter di Mesin Calender Plant R

Proses calendering adalah proses pelapisan kawat baja (steel cord) dengan karet (compound) menjadi steel treatment sebagai salah satu material penyusun dalam proses pembuatan ban. Pada proses produksi steel treatment di Plant R PT ACR tentu tidak lepas dari adanya produk cacat. Metode penelitian yang digunakan adalah metode kuantitatif, peneliti mendapatkan cacat produk seperti supply compound kurang dan compound steel treatment lebih. Pada periode Desember 2020 sampai Februari 2021 frekuensi terjadinya kedua cacat produk tersebut sebanyak 254 kasus untuk supply compound kurang dan 147 kasus untuk compound steel treatment lebih. Penyebab utama kedua cacat produk disebabkan oleh faktor tidak sinkronnya kecepatan conveyor feeding yang men-supply compound ke mesin calender dengan kecepatan mesin calender. Dengan melakukan pengukuran kecepatan secara lansgung terdapat selisih yang cukup jauh. Hal tersebut mengakibatkan supply compound menjadi kurang atau lebih. Dengan permasalahan tersebut maka akan dibuat perancangan sistem kontrol yang dapat mensinkronkan kecepatan conveyor feeding agar sesuai dengan kecepatan mesin calender dengan menggunakan inverter sebagai pengendali motornya. Hasil penelitian ini dinyatakan dalam bentuk tabel yang menunjukan hasil perhitungan untuk memperoleh nilai frekuensi yang dibutuhkan oleh motor induksi. Sebagaimana diketahui kecepatan putaran motor dipengaruhi oleh frekuensi yang didapatkan oleh motor tersebut.

Fungal strains for mycological production of citric acid

Citric acid has become an important raw material for general industrial use with many varied and expanding applications such as iron, steel, treatment and conditioning of industrial water supplies, preparation of alkyl resins, paints and in the printing of calico and textile industries. Mycological Production of citric acid includes preparation and sterilization of different media, culture medium, and seedling of culture tube, incubation of culture tubes, determination of citric acid formed and molasses left unfermented during the course of present investigation. The Present work deals mainly selection of potent strains of fungus.

A review of domestic and foreign experience of steel treatment in CCM tundishes

The modern steelmaking facilities melt as a rule a semi product, which is further subjected to various processes of refining in steel ladle. Recently an additional treatment of the metal in CCM tundish became widespread in the domestic and foreign practice. A tendency of transforming tundish into a multifunctional metallurgical reactor was noted, since more and more technological operations are transferred in it, including alloying, stirring, various methods of heating, modifying and removal of nonmetallic inclusions. Examples of comprehensive utilization of a bloom CCM tundish at some Japanese plants of Kobe Steel in Kakagava presnted, at which the metal is filtered when going through holes in the two partitions thus effectively removing nonmetallic inclusions. New variants of metal blowing off in the tundish by inert gas developed by domestic specialists considered, including a technology for metal blowing off by an inert gas and a facility for the inert gas supply through the stopper of the tundish. Supply of inert gas through the stopper results in efficiency increasing of degassing and nonmetallic inclusions removal as well as submerged nuzzles service time increase, which is particularly important at casting of steels with high content of aluminum. Examples of solutions of metal treatment in tundish by cored and aluminum wire given. Schemes of cored wire introduction into tundish and liquid steel treatment in a CCM mold considered. Considerable attention was given to the problem of metal temperature control in tundish, including by an electric arc, induction and plasma heating. List of domestic and foreign plants presented, implemented facilities of steel plasma heating in the CCM tundish. It was noted, that steel chemical heating in tundish can be applied at unforeseen problems arising at casting.

Objective Laws of Nitrogen Removal in the Vacuum Tank Degasser

This article discusses the problems of efficient removal of nitrogen in the vacuum tank degasser operating at the electric arc furnace shop of Uralskaya Stal (Ural Steel) OJSC in the course of manufacturing of high-quality low carbon steel grades by means of steel grades «2» and «T». In order to determine the reasonable and balanced treatment parameters that ensure the required level of nitrogen content in the above steel grades, an analysis of production data for the period of November-December 2016 has been carried out. This analysis is the basis for identifying the vacuum degassing parameters in compliance with the technological capabilities and well-balanced levels, which allow predicting the level of nitrogen content in steel. To assess the cumulative quantitative effect of the main parameters of vacuum degassing on nitrogen removal, there has been performed a regression analysis. As a result, there have been obtained multiple regression equations describing a rational combination of steel treatment parameters for achieving the required nitrogen removal level.

Supraglottoplasty in Neonates under One Month of Age

Objectives: Examine outcomes of patients 1 month of age or less who received supraglottoplasty. Demonstrate the feasibility and safety of supraglottoplasty in neonates <1 month of age. Methods: Charts were reviewed from 2015-2017. Patients with previously identified laryngomalacia requiring surgical intervention and age 1 month or less were identified. We collected data on age, gender, surgical technique, other airway lesions, time to extubation and discharge, and comorbidities. Results: Six patients met the inclusion criteria of which four were male and two were female. Average age at time of surgery was 19.5 days. All patients had diagnosis of laryngomalacia made on flexible or direct laryngoscopy with increased work of breathing, reports of cyanotic episodes, or oxygen desaturations. All had feeding difficulties, and three had signs and history consistent with gastroesophageal reflux. Two patients underwent supraglottoplasty by CO2 laser treatment alone, one patient received cold steel treatment alone, and the remaining three patients received cold steel with supplemental microdebrider treatment. Out of six patients, five were extubated within 5 days of their procedure. The average time to extubation was 1.8 days. The average time to discharge was 24.25 days following surgery. Two patients required revisions. Conclusions: Supraglottoplasty in children younger than 1 month of age is rare. Despite the rare occurrence, it appears to be feasible early in life in treating laryngomalacia. Neonates with respiratory failure, apneas, and cyanosis, or difficulty feeding due to laryngomalacia should be evaluated and treated with supraglottoplasty.