Composition and Properties of Iron-containing Sludge from the Zavolzhsky Chemical Plant

Li Y., Luo Y., Zhou H., Zhong X., Zhou Z., Li J., Hou H.

There is an increasing requirement to manage large amounts of solid industrial waste, such as red mud (RM) and waste glass sludge (WGS), which pose potential environmental hazards to human health. The purpose of this study was to improve the reactivity of the red mud with mechanical activation. The reactivity was measured by the dissolution efficiency of silicon and aluminium in alkaline solution, the strength index, and the strength of the geopolymer. The optimal condition: WGS addition is 30 wt%; grinding time is 20 min; specific surface area reached 24.65 m2/g; the compressive strength of the geopolymer came to 15.98 Mpa curing for 28 days. XRD, FTIR and XPS were applied to investigate the structural transformation in the process. The environmental characterisation showed a significant leaching concentration of heavy metal(loid)s such as Cr, Zn, Cu, and Mn, which decreases with longer curing periods. The carbon emission results showed that the precursor exhibited enormous potential in energy conservation and emission reduction. The study results demonstrate that cementitious material from two solid waste materials can substantially lower heavy metal leaching values whilst also providing economic benefits. This synthesis pathway can be attained through recycling the two solid wastes, resulting in geopolymers that exhibit potential for a variety of applications.

Zhou Y., Cui Y., Yang J., Chen L., Qi J., Zhang L., Zhang J., Huang Q., Zhou T., Zhao Y., Liu Z., Li B.

Red mud (RM) is a kind of strong alkaline solid waste produced from the aluminum industry, which contributes significantly to environmental pollution and can cause severe health issues.Currently, RM is widely recognized as a potential material for soil remediation because of its rich metal oxide content, such as Fe/Al oxides. However, there is no comprehensive description on the roles of RM in passivation remediation of contaminated soil in mining areas. This review summarizes the mechanisms of passivation of heavy metals (HMs) in contaminated soil by RM, including precipitation, adsorption and ion exchange. Besides the effects of adding RM on soil physicochemical properties, heavy metal forms and ecological environment are further elaborated. Moreover, using the co-hydrothermal carbonization of RM and biomass for enhancing the efficiency of contaminated soil remediation is proposed as the main prospective research. This paper provides technical references for the resource utilization of RM and the treatment of heavy metal-contaminated soil.

Kunin A.V., Ilyin A.A., Morozov L.N., Smirnov N.N., Nikiforova T.E., Prozorov D.A., Rumyantsev R.N., Afineevskiy A.V., Borisova O.A., Grishin I.S., Veres K.A., Kournikova A.A., Gabrin V.A., Gordina N.E.

The work is devoted to investigation of catalysts and adsorbents used in the production of ammonia, methanol, and formaldehyde, hydrogenation of various organic compounds, defluorination of wet phosphoric acid, adsorptive wastewater treatment, and inhibition of combustion chain reactions. Main approaches for the synthesis of adsorption-catalytic systems, governing the composition, structural and textural properties and providing specific functionality, were studied. Those included mechanochemical synthesis and activation, surface modification, precipitation, impregnation, etc. For citation: Kunin A.V., Ilyin A.A., Morozov L.N., Smirnov N.N., Nikiforova T.E., Prozorov D.A., Rumyantsev R.N., Afineevskiy A.V., Borisova O.A., Grishin I.S., Veres K.A., Kurnikova A.A., Gabrin V.A., Gordina N.E. Catalysts and adsorbents for conversion of natural gas, fertilizers production, purification of technological liquids. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 7. P. 132-150. DOI: 10.6060/ivkkt.20236607. 6849j.

Wang M., Liu X.

Red mud is an alkaline by-product produced by alumina plants. The accumulation of red mud is becoming an increasingly serious problem with the growth of the aluminum industry. Various waste treatment methods utilizing red mud as an environmental remediation material have been developed. Red mud environmental remediation materials (RM-ERMs) are environmental remediation materials prepared by activating red mud, synergistically using red mud and other ingredients, or by extracting effective components from red mud. There are three general categories of use for RM-ERMs: for waste water purification, waste gas purification and soil remediation. As well as providing an opportunity to improve the environment through purification technologies, the highly alkaline red mud is consumed in the production of RM-ERMs. The use of RM-ERMs has been shown to be a promising strategy for the simultaneous treatment of various wastes. In this paper, the developregeneration characteristics of various red mud granularent status of RM-ERMs is described, the physical and chemical properties of red mud are introduced, and the active mechanism of RM-ERMs on target pollutants in waste water, waste gas and soil is summarized. Moreover, a discussion on the current existing problems of RM-ERMs provides important tips and suggestions for future research on RM-ERMs. • The advantages and disadvantages of several activation methods of red mud are compared. • The research status of RM-ERMs is described. • The mechanism of action of RM-ERMs on target pollutants in waste water, waste gas, and soil is summarized. • The challenge of applying red mud to soil remediation is presented. • The current development problems and future research needs of RM-ERMs are pointed out.

Boddapati V., Fu M.C., Nwachukwu B.U., Camp C.L., Spiker A.M., Williams R.J., Ranawat A.S.

The purpose was to characterize the independent effect of procedure length on the rates of 30-day perioperative complications, hospital readmissions, and overnight hospital stay in patients undergoing arthroscopic anterior cruciate ligament reconstruction (ACLR). We hypothesized that longer procedure length in primary ACLR increases the risk for post-operative complications. Primary ACLR cases from 2005 to 2015 were identified in the American College of Surgeons National Surgical Quality Improvement Program registry. Patients were categorized into two cohorts based on procedure length, either less than or greater than 90 min. Two equal-sized propensity-matched cohorts were generated to account for differences in baseline and operative characteristics. Thirty-day clinical outcomes were compared using bivariate analyses between propensity-matched groups that controlled for patient-specific factors and concurrent meniscal repair. Multivariate logistic regression models were used to identify independent predictors of hospital readmission and overnight hospital stay. In total, 12,077 ACLR cases were identified. The rate of any 30-day complication was increased in longer procedures relative to shorter procedures (1.6% vs 0.9%, p = 0.006), as were the rates of returning to the operating room (0.6% vs 0.3%, p = 0.03), hospital readmission (1.0% vs 0.3%, p = 0.001), and overnight hospital stay (16.2% vs 6.0%, p < 0.001). Obesity was a risk factor for both hospital readmission and overnight hospital stay, while hypertension, diabetes, chronic obstructive pulmonary disease, and a smoking history were associated with increased rates of overnight hospital stay. The most common reasons for hospital readmission were deep vein thrombosis or pulmonary embolism (25.0% of all readmitted patients), surgical site infection (25.0%), and post-operative pain (14.1%). In this propensity-matched analysis adjusting for baseline patient characteristics and operative factors, procedure length of greater than or equal to 90 min in ACLR was independently associated with an increased risk of hospital readmission and overnight hospital stay. As a surrogate measure of surgical complexity, operative time may be a useful perioperative variable for post-operative risk stratification and patient counseling. III

Zinoveev D.V., Grudinskii P.I., Dyubanov V.G., Kovalenko L.V., Leont’ev L.I.

This review considers the papers aimed to find an effective solution to the red mud utilization problem. Red mud or bauxite residue is a hazardous materials that are generating during production of alumina by the Bayer process. Depending on the composition of bauxite and the technology, production of 1 ton alumina forms from 0.9 to 1.5 tons of this waste. The global inventory of red mud is estimated at about 4 billion ton in 2015. The main quantity of bauxite residue is not processed, but pumped into land-based ponds and it leads to environmental pollution. In 2010 in Hungary a pond containing red mud were collapsed, freeing about 700 thousand m3 of liquid waste, as a result 10 people were died, about 350 houses were destroyed and significant regions were polluted. Red mud obtained by different plants has various chemical and phase compositions. Despite this fact the main components of red mud is iron-containing minerals, so bauxite residue can be considered primarily as a raw material for the metallurgical industry. This part of the review considers pyrometallurgical methods for of red mud treatment, including both methods of low-temperature reduction at temperatures of 1050 - 1200 °C and high-temperature reduction melting, as well as utilization methods of the resulting slags. These slag utilization methods can be used for extraction of alumina, titanium and rare-earth metals, obtaining building materials such as various cements, mineral wool and flux materials for metallurgy. Methods of alkali removing, drying and agglomeration of red mud also considered. It has been shown that the best ways of bauxite residue recycling are the pyrometallurgical methods with obtaining of iron-containing product and slag for the production of building materials or metallurgical fluxes. These techniques make possible to utilize a large amount of red mud with exception of additional waste formation. This is the first part in a series of three related reviews examining the world experience of red mud recycling by various ways.

Terekhova M.V., Gorichev I.G., Rusakova S.M., Artamonova I.V.

The adsorptive abilities of waste of aluminosilicate production in relation to molybdate ions are investigated. The acid way of activation of red mud and the aluminosilicate component (ASC) is offered, allowing to increase their adsorptive properties.

Lomnicki S., Dellinger B.

Studies on the development of supported iron oxide catalysts for PCDD/F decomposition using 2-monochlorophenol as a surrogate test compound are presented. Iron oxide catalysts supported on titania were prepared by two methods: impregnation and the sol-gel method. The latter preparation method resulted in better dispersion of iron oxide on the surface and the formation of gamma-Fe2O3. This is in contrast to the impregnated samples where alpha-Fe2O3 crystallites were formed. Formation of gamma-Fe2O3 resulted in improved reducibility of the active phase that favorably affected the catalytic oxidation properties of the catalyst, i.e., the light-off curves for the sol-gel samples were shifted toward lower temperature. Addition of calcium oxide to iron oxide catalyst further improved the performance of the system through stabilization and increase in the concentration of gamma-Fe2O3 in the sol-gel prepared samples. Addition of calcium oxide has a dual effect on the performance of the catalyst. First, it creates oxygen vacancies in the reduction-resistant Fe2O3 octahedral structures, thereby improving the reducibility of the active phase. Second, iron oxide can transform during decomposition of chlorinated hydrocarbons into iron chloride. Calcium oxide improved the chlorine transfer from the surface iron oxide species, thereby providing a relatively fresh surface for further catalytic oxidation. Comparison of TPR profiles with the position of light-off curves in 2-monochlorophenol decomposition led to the conclusion that Fe3O4 species are the active phase under conditions that facilitate redox cycling between Fe3+ and Fe2+ ions.