Utilization of dispersed waste of ferroalloy production on the basis of metallurgical SHS-process

A review of methods for processing dispersed waste from f loy production was performed. In ferroalloy plants there is a problem of formation and accumulation of cyclone dust (the catch product from crushing – CPC), formed during the grinding and fractionation of ferroalloys. The drawbacks of the known methods for the disposal of such dust are shown. The authors have investigated the possibility of obtaining commercial nitrided ligatures from CPC’s and substandard ferroalloy fines using the technology of self-propagating high-temperature synthesis (SHS). On the basis of the proposed “metallurgical” SHS method, a technology has been developed and the possibility of largescale production of nitrided ferrosilicon, ferrovanadium, ferrochrome and other materials has been shown, which has demand on the world market. Synthesized SHS materials are superior in quality to nitrided ferroalloys obtained by conventional furnace method, in particular, they have a lower content of oxygen, hydrogen and other impurities, and differ in better physical and mechanical properties: density, porosity, strength, and others. Based on the method of metallurgical SHS, the production of nitrided ferroalloys and composite ligatures with the possibility of processing up to 5000 ton per year of cyclone dust of ferrosilicon and other alloys was established in Russia, Magnitogorsk on the production base of scientific and technical production company LLC “STPF “Etalon”. A new approach to the practical implementation of the SHS method is developed and the possibility of using synthesis products in metallurgy is shown. The main application of these products is the use of alloying additives in smelting of a wide range of steels and alloys: transformer, rail, stainless, high-strength structural, and others. Another popular consumer of composite “metallurgical” SHS materials is the refractory production. Modification of traditional refractories used in smelting of cast iron, steel and non-ferrous metals with new composite SHS materials based on nitrides, borides, carbides and other refractory compounds can significantly increase the service life and reduce the expenses for refractories.

Influence exerted by somatic pathology on risks of occupational lung fibrosis in workers employed at refractory production

Occupational lungs and bronchial pathology occurs not only under exposure to dusts, their aerosol structure and aggression, but also depends on individual properties of a body. The latter can determine either increased body resistance or susceptibility to occupational pathology occurrence. Our research goal was to determine influence exerted by somatic pathology on occupational lung fibrosis occurrence as well as to estimate prevalence of risk factors for cardiovascular and metabolic pathology occurrence in workers employed at refractory production. At the first stage 449 workers employed at refractory production were examined at a periodical medical examination (PME). Patients’ average age was 41.59±0.45 and average work experience was 14.47±0.39 years. At the second stage 172 workers were examined at an occupational pathology center; 75 out of them were workers who had silicosis and were included into the test group and the remaining 97 workers didn’t have any occupational pathology and were included into the reference group. Both groups were comparable as per sex (p = 0.0052) and work experience under exposure to dusts (р = 0.862). Workers examined at a PME most frequently had overweight and obesity (68 %). Arterial hypertension (AH) prevalence amounted to 19.5%; carbohydrate metabolism disorders, 19.8 %; 48.1 % workers had hypercholesterolemia. Patients with silicosis had certain disorders significantly more frequently than workers with long work experience but without any occupational pathologies; those disorders were AH, cardiac muscle hypertrophy in the left ventricle, ischemic heart disease, heart rate disorders, as well as mixed (obstructive and restrictive) breath mechanics disorders. We determined some factors that authentically produced certain effects on occupational lung fibrosis occurrence in workers employed at refractory production. Median time of silicosis occurrence was significantly shorter (by 11.5 years) among workers with severe AH, arrhythmia (by 13 years), lower hemoglobin in blood (by 11.5 years). Besides, silicosis occurred significantly earlier (by 10.8) among women than among men.

Influence exerted by somatic pathology on risks of occupational lung fibrosis in workers employed at refractory production

Occupational lungs and bronchial pathology occurs not only under exposure to dusts, their aerosol structure and aggression, but also depends on individual properties of a body. The latter can determine either increased body resistance or susceptibility to occupational pathology occurrence. Our research goal was to determine influence exerted by somatic pathology on occupational lung fibrosis occurrence as well as to estimate prevalence of risk factors for cardiovascular and metabolic pathology occurrence in workers employed at refractory production. At the first stage 449 workers employed at refractory production were examined at a periodical medical examination (PME). Patients’ average age was 41.59±0.45 and average work experience was 14.47±0.39 years. At the second stage 172 workers were examined at an occupational pathology center; 75 out of them were workers who had silicosis and were included into the test group and the remaining 97 workers didn’t have any occupational pathology and were included into the reference group. Both groups were comparable as per sex (p = 0.0052) and work experience under exposure to dusts (р = 0.862). Workers examined at a PME most frequently had overweight and obesity (68 %). Arterial hypertension (AH) prevalence amounted to 19.5%; carbohydrate metabolism disorders, 19.8 %; 48.1 % workers had hypercholesterolemia. Patients with silicosis had certain disorders significantly more frequently than workers with long work experience but without any occupational pathologies; those disorders were AH, cardiac muscle hypertrophy in the left ventricle, ischemic heart disease, heart rate disorders, as well as mixed (obstructive and restrictive) breath mechanics disorders. We determined some factors that authentically produced certain effects on occupational lung fibrosis occurrence in workers employed at refractory production. Median time of silicosis occurrence was significantly shorter (by 11.5 years) among workers with severe AH, arrhythmia (by 13 years), lower hemoglobin in blood (by 11.5 years). Besides, silicosis occurred significantly earlier (by 10.8) among women than among men.

Improving the technology for the preparation of clay raw materials for the refractory production

The technical solution of the screen with increased efficiency of separation of clay rock mass is considered. The most rational design of non-driven grate screens cantilever and spring-loaded screens — has been identified. A mathematical model is presented and a methodology for calculating the screen parameters is presented. It is shown that when selecting the appropriate parameter values for the grid-irons of the screening surface, the screens can be used for screening clay mass.

IX scientific-practical conference «Actual problems of refractory production»

В Санкт-Петербурге 8‒9 ноября 2018 г. состоялась IX научнопрактическая конференция «Актуальные проблемы огнеупорного производства». Организатор конференции ― Ассоциация производителей и потребителей огнеупоров «Санкт-Петербургский научнотехнический центр». На конференции были представлены доклады, посвященные научным исследованиям и разработкам в области технологии огнеупоров, нормативно-правовой базы в области огнеупоров, контролю качества огнеупоров, а также национальной стандартизации.

The experience of the SC «Borovitch Refractory Works» production application at the SC «Oskol Electrometallurgical Works»

The results of the cooperation between SC «Borovitch Refractory Works» and the SC «Oskol Electrometallurgical Works» (SC OEW) with regard to the supplying and operational activity of the wide range of the refractory production items are given in the article. The basic development trends are pointed out which can improve and optimize the physical and chemical parameters of the supplied refractories. The main innovative refractory materials and the completed projects are regarded which have amended the technical and economic indexes of the heat vessels at the SC OEW engaged at the main metallurgical processing stages.Ill.7. Ref. 4. Tab. 5.

The recycling materials using in the refractory production

The investigating results are given for the ferrouschromium slags using as the refractory materials to prepare the refractory concretes. The temperature range of their application was defned. It was established that the magnesia oxide addition considerably reduced the Chromium VI formation during service in composition of the refractory materials manufactured on base of the ferrous-chromium slags. Ref. 5. Tab. 4.