Наталия Евгеньевна Кручинина

Актуальность. Вопросам поиска новых сырьевых источников редкоземельных и рассеянных металлов уделяется все больше внимания. Диопсид – новый и весьма перспективный источник добычи соединений скандия, позволяющий получать широкий спектр неорганических продуктов, обеспечивающих экономическую целесообразность производства. Цель. Разработка комплексной энерго- и ресурсосберегающей технологии переработки диопсида с получением скандиевого концентрата и широкого спектра неорганических продуктов. Методы. Для исследования состава кислых растворов использовали метод атомно-эмиссионной спектроскопии с магнитной плазмой. Результаты и выводы. Получены образцы импрегнатов на основе макропористых активированных углей, пропитанных смесью Д2ЭДФК/ТБФ. Полученные образцы продемонстрировали высокую емкость по отношению к соединениям скандия, а отказ от жидкостной экстракции позволит существенно повысить уровень производственной безопасности. Использование двух инновационных реэкстрагентов на основе смеси аммонийных солей или оксиэтилидендифосфоновой кислоты позволяет улучшить экологические и экономические показатели процесса реэкстракции. Впервые предложена технология соосаждения соединений скандия с использованием оксидов кальция/магния. Прокаленный скандийсодержащий концентрат содержит от 0,8 до 1,4 % скандия. Маточные растворы процесса вскрытия могут быть нейтрализованы с использованием магнийсодержащих отходов с получением сульфата магния – ценного материала для строительной, сельскохозяйственной и иных отраслей промышленности. Осадки процесса нейтрализации могут быть частично возвращены на стадию вскрытия диопсида или использованы в качестве сырья для производства комплексных титансодержащих коагулянтов. Разработанная на основе совокупности технологических приемов концепт-схема является комплексной и сопровождается минимальным образованием сточных вод и твердых отходов.

Relevance. Traditional coagulants for water treatment based on aluminum or iron salts are no longer able to solve the tasks assigned to them, and stricter requirements for purified water dictate the need to search for new methods and reagents for water treatment. The most promising direction for improving the efficiency of water purification is the introduction of complex titanium-containing reagents that have demonstrated high efficiency in wastewater treatment of complex composition. Aim. To compare the coagulation efficiency of traditional and complex titanium-containing coagulants in the wastewater treatment of the dairy and fat-and-oil industry. Results and conclusions. The paper investigates the effectiveness of traditional aluminum-containing coagulants (aluminum oxychloride, iron (III) chloride) and a complex sulfate-chloride coagulant based on aluminum salts modified with titanium compounds. It is shown that the use of complex sulfate-chloride coagulant allows the most effective reduction of the chemical oxygen consumption index, reflecting the content of organic compounds in water, while traditional coagulants are significantly inferior in the effectiveness of reducing this indicator. The use of a complex reagent made it possible to significantly minimize the residual content of suspended solids at lower effective doses of coagulant (60–80 mg/dm3 for complex sulfate-chloride coagulant – 95–98% purification efficiency versus 80 mg/dm3 – no more than 44–52.5% for traditional reagents) for the wastewater samples under study compared with traditional reagents. It is proved that the combination of coagulation purification with the use of complex sulfate-chloride coagulant and the flotation makes it possible to achieve the discharge standards established by the Vodokanal for the content of fats and suspended solids.

Increasing attention is paid to issues related to electroplating wastewater treatment. It is equally important to search for, and introduce new highly efficient technologies of processing bulk mineral waste accumulating at various plants. As part of the conducted research, we assessed an opportunity of using brucite-containing waste from refractory manufacturing as an experimental chemical agent for precipitation of heavy metal ions. Efficiency of removal (precipitation) of heavy metal ions was studied on model wastewater of rinsing parts on the electroplating section. It has been established that an efficient dose of brucite-containing waste to reach a standard residual concentration of heavy metals of 0.05 mg/dm3 or less is 2.0 g/dm3. It has been determined that minimum period of the brucite-containing waste/wastewater contact is 45 minutes. Heat treatment of brucite-containing waste at 500 оС during 60 minutes contributes to a considerable increase in heavy metal precipitation efficiency and reduction of a dose of the chemical agent for precipitation to 1.5 g/dm3 without losing efficiency. Water treatment from heavy metals is supposed to include parallel processes of neutralization, forming poorly soluble hydroxides, sorption of combinations of heavy metals on the surface of brucite-containing waste, and processes of ion exchange on the surface of magnesium oxides. Using wastes from refractory manufacturing in processes of engineering protection of environment will contribute to not only reducing volumes of waste dumping, but also making the first step to implementing the Zero Waste concept as part of closed-loop economy.

The quartz-leucoxene concentrate generated in the development of the Yarega oil and titanium deposit represents large-scale waste, for which no industrial application has yet been found. The content of titanium compounds in the enriched concentrate may reach 50 wt%, which confirms the high relevance of this work. The technologies existing currently envisage separate enrichment options for the concentrate upstream of the selective chlorination process. As part of this research work, pyrometallurgical processing of a quartz-leucoxene concentrate was studied, aimed to produce titanite (sphene). The onset temperature of the solid-phase reaction of titanite synthesis in the CaO–TiO2–SiO2 system was established at 1330 °C. The optimal conditions for the pyrometallurgical treatment process are as follows: 1400 °C for three hours at a stoichiometric ratio of CaO–TiO2. A titanite phase and significant impurities of silicon dioxide released from the quartz-leucoxene grains have been identified in the pyrometallurgical processing products. The process of hydrometallurgical reсovery of titanium compounds occurs most intensively at a sulfuric acid concentration of 60 % and at 140–145 °C (boiling of a 60 % H2SO4 solution), with the recovery values exceeding 90 %. The leaching process sediment represents a mix of calcium sulfate, silicon dioxide, as well as unreacted components. A technology concept is proposed for the comprehensive pyro- and hydrometallurgical processing of quartz-leucoxene concentrates to produce raw materials for the manufacture of titanium dioxide/phosphate and complex titanium-containing coagulants. The research was supported by the Perm Scientific and Educational Center «Rational Subsoil Use», 2023.

DOI: 10.31897/PMI.2023.15 Leucoxene-quartz concentrate is a large-tonnage by-product of development of the Timan oil-titanium field (oil-saturated sandstones) which is not commercially used at present. High content of titanium compounds (to 50 % by weight) and lack of industrial, cost-effective, and safe technologies for its processing determine a high relevance of the...

It has been established that in the process of joint heat treatment of a mixture of red mud – quartz-leucoxene concentrate, a change in the chemical composition occurs with the formation of pseudobrookite, which has an increased chemical activity compared to the original quartzleucoxene concentrate. It has been established that the product of the combined heat treatment of red mud and acid tar consists of a mixture of aluminum, iron, and titanium sulfates that are readily soluble in water. Calcium sulfate and silicon compounds have been isolated as insoluble impurities. It is confirmed that in order to achieve the maximum degree of interaction, the mixture of red mud and acid tar must be heated at a rate of no more than 1–2 °C/min until 550 °C and time 60 min.

The main directions of alternative use of scale, a metal-containing waste material from forging and pressing shops at metallurgical enterprises, were suggested and researched within the framework of this work. Scale composition from the processes of heat treatment and forging of steel components from forging and pressing shops at the machine- building plant in the Moscow region was examined. It was established that up to 99 % of scale is presented by magnetic phases of iron oxides, supposedly in the form of Fe3O4, and alloying components do not practically transit in scale. The technology of sulfuric acid and hydrochloric scale processing with obtain of coagulants is suggested for purification of waste water at galvanic sections or hydrochloric pickling solutions respectively. The technology of scale use as filtrating loading for the processes of purification and neutralization of chromium-containing waste water is proposed. Hugh reducing ability of scale as a reactant for purification of acidic waste water was established in the wide range of initial concentration values of chromium (VI) compounds. Possibility of scale use as Fe-containing additive for pyrometallurgical processing of quartzite-leucoxene, a large-capacity titanium-containing mineral waste, was examined. It was established that chemically active pseudobrookite is the final conversion product; it can be used as raw material for manufacture of wide spectrum of commercial products.

Quartz-leucoxene ore and its processing concentrates are valuable titanium-containing raw materials, however a comprehensive processing technology for the ore is yet to be developed. This paper studies the high-temperature processes occurring in a system containing quartz-leucoxene concentrate with an iron-containing additive. It has been established that, depending on the atmosphere of the pyrometallurgical processing and the type of the iron-containing additive, phases of ilmenite (in an inert atmosphere) or pseudobrookite (in an oxidizing atmosphere) may be obtained. The possibility of using heat treatment and forging scale (a common large-tonnage metallurgical production waste) as an iron-containing additive has been studied. It has been established that pseudobrookite will be the final product. For all concentrate/iron-containing additive systems studied, depending on the thermal effects, the possibility of intermediate reduction/oxidation reactions for iron oxides and of the formation of Fe2TiO4 intermediate phases (followed by their transition to the pseudobrookite phase) was identified. The minimum triggering temperatures for the conversion process of quartz-leucoxene concentrate Fe2TiO5 and FeTiO3 have been established, as well as the main thermal effects, mass losses, and melt crystallization parameters, which allows optimizing the conditions for pyrometallurgical conversion. The data obtained enables effective process scaling. It has been established that impurity components in the concentrate (up to 7–9 wt% on average) enter into intrasystem reactions with the formation of calcium titanates (sphene CaSiTiO5) and magnesium (MgTiO3, MgTi2O5, Mg2TiO2).This is a continuation of the article titled «Principles of pyro-hydrometallurgical processing of quartz-leucoxene concentrates with the formation of a pseudobrookite phase» («Obogashchenie Rud», 2021, No. 3).