Technical Lignosulfonates Research Articles

DRILLING MUD THINNER BASED ON TECHNICAL LIGNOSULFONATES FROM WASTE OF CATALYST PRODUCTION

The article presents the results of research on obtaining liquid thinners for drilling muds from waste generated at one of the technological stages in the production of sulfocationic catalysts from technical lignosulfonates.During the production of heterogeneous sulfo-cationic sorbents and catalysts from technical lignosulfonates, acidic waters containing low-molecular-weight fractions of lignosulfonates, residues of hemicellulose hydrolysis products, water-soluble, and extractive substances are generated at the stage of washing off the residual acid. One of the ways to utilize the generated waste could be its further processing into new reagents. Therefore, the aim of this work was to develop a formulation of a thinner based on the generated waste and study its effectiveness in typical drilling muds. A dry industrially produced lignosulfonate was used as a reference reagent.The possibilities of using the resulting liquid waste to obtain highly effective thinners for drilling muds based on lignosulfonates are shown. It is revealed that the resulting reagent reduces the rheological parameters of the drilling mud, is comparable in effectiveness to dry industrially produced lignosulfonate (0.5 % by weight and 1 % by weight), and is technologically easy to use. In fresh water solutions, the modified form of the reagent with the addition of oxyethylidenediphosphonic acid is more effective, while in mineralized solutions the unmodified form is more effective.

Dehydration and Environmentally Friendly Thermal Processing of Excess Activated Sludge

Introduction. Currently, there is a problem with the accumulation of large amounts of production waste. One type of this waste is excess activated sludge, which is a waste product from biological wastewater treatment that has a high moisture content. When excess activated sludge is deposited in beds, problems can arise related to changes in the gas-air environment, the release of unpleasant odors, as well as the contamination of groundwater and soil. Prolonged presence of sediment in sludge beds in oxygen-free conditions leads to its decay and deterioration of moisture-yielding properties. For these reasons, the development of new methods for disposing of large volumes of waste generated during wastewater treatment is essential. The aim of this research is to develop a technique for preliminary neutralization and thermal treatment of excess activated sludge using energy waste. Materials and Methods. The work used excess activated sludge with a moisture content of 98.2% (waste of hazard class IV). Water treatment sludge (waste of hazard class V) was used as a reagent to increase moisture yield. For experimental studies on dehydration, a laboratory centrifuge Elmi CM-6M.01 was used. Tests were conducted under various conditions (500, 1 000, and 1 500 revolutions per second for 1, 2, and 3 minutes), and the value of centrifugation was determined as a criterion for moisture yield in the sludge. Fuel pellets were produced by rolling with technical lignosulfonate as a binding agent. Elemental analysis of the samples was conducted to study the possibility of thermal treatment using an EA 3 000 Euro Vector Analyzer. Results. A comprehensive technology has been developed to clean the resulting gas emissions from solid particles formed during the combustion of fuel pellets and remove them from the furnace in the form of fly ash along with the outgoing gases. This technology also removed sulfur oxides, nitrogen oxides, and polychlorinated dibenzodioxins and dibenzofurans, while beneficially utilizing flue gas heat by reducing its temperature from 900–1 200°C to 140°C. Discussion and Conclusion. The approach proposed in this article for the processing and disposal of large volumes of waste allows for the reduction of moisture content of excess activated sludge and the use of this waste as a secondary energy source. This method is environmentally friendly and addresses both technical and environmental challenges, such as the effective recycling of industrial waste and reducing the anthropogenic impact on soil, air, and groundwater. It also provides an opportunity to generate additional electrical and thermal energy through thermal utilization of waste. The results of this work indicate that it is possible to integrate the use of various types of industrial waste (sewage sludge, water treatment waste, and pulp and paper industry waste) as secondary energy sources. These findings have practical implications for enterprises in both the municipal and industrial sectors with wastewater treatment facilities.

Research of the plasticizing binder type and quantity influence on the properties of pressed alumina­zirconia­silica refractories

Comparative research of the plasticizing binder type (technical lignosulfonate sodium aqueous solution, plasticizing additive on polycarbonate base aqueous solution, as well as technical lignosulfonate sodium and orthophosphoric acid (H3PO4) aqueous solutions mixtures in 3:1 and 1:1 ratio) and its quantity influence on the properties indexes of pressed alumina­zirconia­silica (AZS) refractories were carried out.
 If necessary, the possibility of using any of the studied plasticizing binders for pressing AZS refractories was established. Each of the studied plasticizing binders ensures the receiving of AZS refractories with high indexes of properties. There is a slight tendency to improve the properties of unfired and fired samples of some compositions with binders from plasticizing additives on polycarbonate base aqueous solution and technical lignosulfonate sodium with H3PO4 aqueous solutions mixtures, compared to samples in which the binder is technical lignosulfonate sodium aqueous solution is observed. The best, according to the indicated tendency, is a plasticizing binder from technical lignosulfonate sodium and H3PO4 aqueous solutions mixture in 1:1 ratio. Binders from plasticizing additive on polycarbonate base aqueous solution, technical lignosulfonate sodium and H3PO4 aqueous solution mixture in 3:1 ratio, and technical lignosulfonate sodium aqueous solution are then placed. This tendency should be considered when choosing a plasticizing binder for pressing AZS refractories.
 The raw material base for AZS refractories production has been expanded using the research results.

Core mixture based on modified lignosulfonate.

Technical lignosulfonates (LST) are a by-product in the production of cellulose by the sulfite method. Lignosulphonates are the third most widely used binder in foundries (after clay and liquid glass). They are used for rawforming, dryforming, making rods in heated tooling, non-stick paints, etc. Molding mixtures with only one LST are not used, as they have low strength due to the occurrence of stresses and cracks in the films of this binder. In addition, LST, like all water-soluble binders, have a suspended hygroscopicity, which reduces thestrength of the rod (mold) during storage. However, when hydrophobic additives are introduced into the LST, the latter disadvantage decreas-es.Previously, calcium hydrosulfate (cooking acid with a calcium base) was used for sulfite cooking of cellulose and calcium lignosulfanates were in the LST. Now mainly cooking acids with sodium mixed with Ca–Na are used, and an-yway, the strength properties for mixtures are insufficient. In order to eliminate these disadvantages, plasticisers and modifiers are added to LST. For forming raw, dry and making rods, LST with a sodium base is used, lignosulfonate modified with hexavalent chromium (CrO3) is used, clay mixtures are introduced, LST is used with other binders, as a combined binder (for example, USK). The aim of the work is to develop a modifying additive based on the binder LST-USK, a component of the core mixture used at JSC “NTKRZ”, which is not inferior to the known core compositions, with its subsequent possible use in production. As a second additive, and the possibility of introducing it in production, the composition of the core mixture with sunflower oil was tested on the casting radiator MS-140-M2-500.

Directions for Improving the Compositions of Reverse Emulsions for Well Plugging

Well killing is the most common technological process in oil production. Inverse emulsions are used as an effective fluid in the combined killing method. At present, some potential possibilities of inverse emulsions have not been analyzed both in terms of improving their compositions and technological methods of practical implementation. The paper considers a number of promising research areas for obtaining, improving the compositions of inverted emulsions and the method of their application with injection into the bottomhole formation zone before filling the wellbore with mineralized water. Natural oils of co-emulsifiers - ethoxylated oil-soluble surfactants, and filtration reducers - technical lignosulfonates, starch, latex were proposed as constituent components of hydrocarbon media. Attention was focused on the need for experimental evaluation of the rate of settling of reverse emulsions along the wellbore in formation water and oil, obtaining and studying stable reverse emulsions using high-density salts of CaBr2, ZnBr2, ZnCl2, polyhydric alcohols.

Selective Electrochemical Degradation of Lignosulfonate to Bio-Based Aldehydes.

A sustainable electrochemical pathway for degradation and thermal treatment of technical lignosulfonate is presented. This approach is an opportunity to produce remarkable quantities of low molecular weight compounds, such as vanillin and acetovanillone. For the electrochemical degradation, a simple two-electrode arrangement in aqueous media is used, which is also easily scalable. The oxidation of the biopolymer occurs at the anode whereas hydrogen is evolved at the cathode. The subsequent thermal treatment supports the degradation of the robust chemical structure of lignosulfonates. With optimized electrolytic conditions, vanillin could be obtained in 9.7 wt% relative to the dry mass of lignosulfonate used. Aside from vanillin, by-products such as acetovanillone or vanillic acid were observed in lower yields. A new and reliable one-pot, two-step degradation of different technically relevant lignosulfonates is established with the advantages of using electrons as an oxidizing agent, which results in low quantities of reagent waste.

Cold-curing mixtures based on biopolymer lignin complex for casting production in single and small-series conditions

<abstract> <p>This study proves that lignin-based biopolymer materials can be employed as starting materials for the synthesis of novel casting binders that fulfill the current level of characteristics. The optimal concentration of the binder in the mixture was experimentally determined to be 5.8%–6.2%. It has been demonstrated in practice that the employment of ammonium salts as a technical lignosulfonate (TLS) modifier can result in the provision of cold (room temperature) curing of a mixture based on them. It was proposed to use as a technological additive that boosts the strength characteristics of a mixture of substances carboxymethyl cellulose (CMC). In a variety of adhesive materials, it is utilized as an active polymer base. The concentration limits for using CMC in the mixture are set at 0.15%–0.25%. To improve the moldability of the combination, it was suggested that kaolin clay be used as a plasticizing addition. The concentration limits for using a plasticizing additive are set at 3.5%–4.0%. The produced mixture was compared to the analog of the alpha-set method in a comparative analysis. It was discovered that the proposed composition is less expensive, more environmentally friendly, and enables the production of high-quality castings. In terms of physical, mechanical, and technological properties, the created composition of the cold curing mixture is not inferior to analogs from the alpha-set method. For the first time, a biopolymer-based binder system containing technical lignosulfonate with the addition of ammonium sulfate and carboxymethyl cellulose was used in the production of cast iron castings on the case of a cylinder casting weighing 18.3 kg from gray cast iron grade SCh20. Thus, it has been proved possible for the first time to replace phenol-based resin binders with products based on natural polymer combinations. For the first time, a cold-hardening mixture based on technological lignosulfonates has been developed without using hardeners made of very hazardous and cancer-causing hexavalent chromium compounds. But is achieved through a combination of specialized additives, including kaolin clay to ensure the mixture can be manufactured, ammonium sulfate to ensure the mixture cures, and carboxymethyl cellulose to enhance the strength properties of the binder composition. The study's importance stems from the substitution of biopolymer natural materials for costly and environmentally harmful binders based on phenolic resins. This development's execution serves as an illustration of how green technology can be used in the foundry sector. Reducing the amount of resin used in foundry manufacturing and substituting it with biopolymer binders based on technological lignosulfonates results in lower product costs as well as the preservation of the environment. Using lignin products judiciously can reduce environmental harm by using technical lignosulfonates, or compounds based on technical lignin. The combination is concentrated on businesses with single and small-scale manufacturing because it is presumable that this is merely the beginning of the investigation. This study confirms the viability of creating a cold-hardening combination based on technical lignosulfonates in practical applications and supports this with the castings produced, using the creation of a gray cast iron cylinder casting as an example.</p> </abstract>

Development of peat-containing mixtures for thermal insulation of steel castings tops using glyceroborates

To insulate the castings tops, heat-insulating shells are made from peat-containing mixtures, which are characterized as inexpensive, non-scarce and environmentally friendly substances. However, due to their low strength characteristics and a high degree of fire hazard, their widespread use in foundry is limited. The article presents the results of research on the development of effective mixtures for insulating the steel castings tops using peat and borate compounds. The development of an effective heat-insulating mixture for heat insulation of castings on the basis of peat mass using glyceroborate of the general formula (СН2О)3ВОН, glyceroborate of oleic acid of the general formula С17Н33СООСН(СН2О)2ВОН and glyceroborate of stearic acid of the general formula С17Н35СООСН(СН2О)2ВОН. To achieve this goal, the following tasks were solved: determination of the tripoli content in the peat mass, at which the value of the thermal conductivity coefficient is 0.42 W/(m ∙ K) and the indicator of the mixture crumbling at this value; study of the influence of glyceroborates on binding properties of technical lignosulfonates; creation of a heat-insulating mixture from peat, tripoli, lignosulfonate and glyceroborates; study of crumbling, formability, ultimate compressive strength in a wet state and ultimate tensile strength in a dry state of an insulating mixture in dependence on the content of glyceroborates. Studies of the influence of glyceroborates on the binding properties of technical lignosulfonate have established an increase in its binding properties in relation to fillers by 35–39 %, which helps to reduce crumbling, improve formability and increase the strength properties of heatinsulating mixtures. Tests of mixtures consisting of peat, tripoli, lignosulfonate and glyceroborates for crumbling, formability, compressive strength of samples in a wet state and tensile strength of dry mixtures under tension showed that the addition of glyceroborate compounds improves the technological performance of the mixture. An effective heat-insulating mixture has been developed for the steel castings tops of the following composition, wt.%: peat mass — 60; tripoli — 20; technical lignosulfonate — 10–12; glyceroborate (oleic acid glyceroborate, stearic acid glyceroborate) — 8–10.

Синтез коллоидного серебра с использованием лигносульфонатов

Colloidal silver solutions can be used as catalysts for carrying out various chemical transformations of organic substances and solving the problems of disposal of toxic compounds, as well as antibacterial agents for combating pathogenic microflora, in the manufacture of lubricants and light-absorbing materials, coatings, sensors, conductive pastes, and high-performance electrode materials. The research purpose is to study the synthesis of colloidal silver using a solution of technical lignosulfonates (LST) as a stabilizer. Colloidal silver was synthesized as a result of the reduction-oxidation (redox) reaction of Ag(I) cations with glucose at 100 °C in the presence of lignosulfonates. The reaction was carried out in an alkaline medium, which is provided by the addition of ammonia water. Electronic spectroscopy was used to control the synthesis of colloidal silver. After the reaction, the solution turned dark brown and an intense absorption band with a maximum at 400 nm appeared on the electron spectra. The effects of reagent consumption and synthesis duration were studied. It was found that the optimal reagent consumption in the colloidal silver synthesis is as follows: 2.5–5 g glucose / g Ag, 0.3–1 g LST / g Ag, and 3–5 g NH3 / g Ag. The synthesis duration is 2–5 min. The resulting colloidal silver solution is stable for several months. Partial stratification without precipitation is observed during the solution storage. It is shown experimentally that the stratification is followed by a redistribution of colloidal silver particles. Electron spectroscopy confirmed the absence of colloidal silver particles in the upper layer. The reaction kinetics has been studied in experiments carried out under thermostatically controlled conditions at temperatures from 50 to 100 °C. The kinetic dependence is described by a first-order equation at the initial stage of the reaction, the duration of which depends on the temperature. The duration of the active part of the kinetic curves is 15–90 % of the total reaction time. The logarithm of the rate constant on the active section was proved to depend linearly on the reverse thermodynamic temperature (pair correlation coefficient is 0.9887). The activation energy was 47 kJ/mol. For citation: Plakhin V.A., Khabarov Yu.G., Veshnyakov V.A. Synthesis of Colloidal Silver Using Lignosulfonates. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 184–195. DOI: 10.37482/0536-1036-2021-6-184-195

Studying rheological properties and reactivity of acid solutions with thickening additives

This article is the result of studies of rheological properties and reactivity of acid solutions of technical lignosulfonate, decationized lignosulfonic acid, and hydrochloric acid with the addition of lignosulfonate. Compositions that include lignosulfonate can be used as displacement agents in the development of watered layers with inhomogeneous reservoir properties. The use of thickening additives in acid solutions solves several problems. Slowing the reaction rate will allow the acid flow to leak in the reservoir deeper, with saving of acid capacity. The height viscosity of the compositions increases the sweep efficiency of the bottomhole zone by acid treatment. Due to the fact that thickening additives in the compositions have a high concentration, selective isolation of highly permeable areas of the reservoir can be realized, which, in turn, contributes to the formation of new pore channels.We evaluated the reactivity of acid solutions with thickening additives in the interaction with carbonate samples. The presence of technical lignosulfonate in an acid solution reduces the dissolution rate of samples. Slowing down the reaction rate will allow the acid composition to form long channels of high permeability, which, in turn, increases the efficiency of acid treatment.

The waste-to-energy technology of the energy sector

Nowadays a problem of reducing anthropogenic impact on the environment is important. In the present article a perspective method of waste-to-energy technology of the energy sector is reviewed. This article focuses on the carbonate sludge (large-tonnage industrial waste) produced by power stations that is used as a sorption material, and adsorption properties of carbonate sludge, its influence on activated sludge is considered. Sludge is a microporous sorbent which is confirmed by the sorption curves for oil products and ammonia nitrogen. The carbonate sludge increases the activated sludge volume index by improving its sedimentation properties and the efficiency of centrifugation during activated sludge dewatering due to the rupture of hydrate shells of activated sludge. Granules that can be used as a fuel are obtained at the following mass ratios: excess activated sludge - 70%, carbonate sludge - 8%, binder - 22% by weight (starch and technical lignosulfonate). The production technology of fuel granules for incineration has been developed based on the research results.

The structure formation mechanism in wet coal fines briquetting with an active binder

This paper presents the results of studies of the structure formation mechanism for briquettes made from coal fines (sludge, coal dust, and fines), with the use of powdered technical lignosulfonate (100 % Na base) as the binder. It has been established that, when briquetting fine coal fines with active finely-dispersed binders in an air-dry state, the structure formation mechanism of the briquette does not fully align with any of the existing hypotheses. As a result of the research, a theoretical substantiation is proposed for the hypothesis of wet coal sludge briquetting with the use of active finelydispersed binders in an air-dry state. It has been shown that the walls of capillaries and pores in the central part of the briquette experience precipitation from the fluid systems, dissolved by internal moisture, and of coarse particles and a certain amount of the binder entrained in the fluid. Further, a lean fluid advances to the surface of the briquette, consisting mainly of moisture and an excess amount of the active binder, dissolved in it. In the near-surface compacted area of the briquette, the binder is adsorbed on coal particles and the moisture released in the process of thermal destruction and adsorption evaporates. The practical use of the concepts obtained allows controlling the structure formation processes to improve strength without increasing the binder content through layer-by-layer reinforcement of the briquette mass with a closed surface, which significantly improves the process results.

The use of technogenic raw materials to produce a high-alumina chamotte

When fused corundum is crushed, a finely dispersed powder is formed with an Al2O3 content of 93–95%, in the form of substandard material. It is advantageous to utilize this powder to obtain high-alumina chamotte with Al2O3 content of more than 62%. High-alumina aggregate (chamotte) was obtained by semi-dry technology with intermediate briquette molding from a mixture of corundum dispersed powder and enriched kaolin. Based on a final Al2O3 content of 65 wt. % the batch composition of the mass to produce a high alumina aggregate (chamotte) was calculated. From a mixture of dispersed corundum powder and kaolin moistened with a 5–7% technical lignosulfonate solution with a density of 1050 kg·m−3, a briquette was formed at a specific pressing pressure of 15–20 MPa. The briquette was fired at a temperature of 1700°C. The fired briquette had a strength of 164 to 193 MPa. The water absorption of briquettes was 11–12%. The phase composition of the briquette is represented mainly by corundum and mullite. The enriched kaolin did not show sintering effect on fine corundum.

Water impermeability of hydraulic concrete based with thermal power plant waste substrate

One of the main factors in ensuring the reliability of concrete used in the construction of hydraulic and reclamation facilities is their waterproofing and frost resistance, and the design of the optimal composition of concrete to ensure waterproofing is of great importance. The main goal of the study was to select the water/cement ratio of the concrete mix not only in terms of concrete strength but also in terms of concrete strength, to ensure the optimal concentration of aggregates for dense structural concrete and finally to increase the water permeability of hydraulic concrete using microfillers and chemical additives. In the study, industrial ash (Angren Thermal Power Plant) was used to modify technical lignosulfonates and prepared a plasticizer L-2 chemical additive. Studies have shown that if the size of pores and capillaries that occur in the concrete structure is less than 10-5 cm, they will not allow free water to pass through. But if these dimensions are larger than 10-5 cm, they will have the property of water permeability. The size of the pores formed in the cement gel, which is usually used in the preparation of concrete, is less than 10-5 cm, and they are impermeable to water. However, the sizes of capillaries and pores of different sizes formed in the concrete structure may vary depending on the factors listed above (10-6 - 0.2 cm). Based on the research, the technological factors affecting the waterproofing of hydraulic concrete were analyzed. It was argued that the use of L-2 plasticizer chemical additive in the amount of 0.25% of the cement mass in the preparation of hydraulic concrete can reduce the water-cement ratio by 18% and increase the waterproofing of hydraulic concrete by 3 times. In addition, it was considered that by waterproofing open pores and capillaries in freshly poured concrete, their waterproofing can be increased by 20. … 30 times.

HYDRO-ISOLATING DECORATIVE PLASTER FOR CONCRETE RESERVOIRS

Development of Ukrainian build materials production takes place in the direction of new competitive dry build mixtures creation with polyfunctional and decorative setting, including for implementation of hard hydro-isolating plaster of concrete reservoirs, assuming introduction of dyes-pigments either directly in the complement of mixture or in the special composition for implementation of decorative integumentary layer. The competitiveness of such dry build mixture is provided by the innovative decision on plasticiting, compacting and hydro-phobization at hydrative hardening of Portland-cement composition due to introduction to its composition in small concentrations of inexpensive and unscarce additions, in particular, of calcium nitrate. For expansion of application domain of such hydro-isolating compositions introduction of pigments-dyes with the simultaneous presence of modifying additions is possible, in particular, of ammonium sulfate, sulfite yeast brew or technical lignosulfonate (in the amount of to 0,2 mass. %) or redispersible powders of a vinyl-acetate type (to 0,005 – 0,1 mass. % from mass of cement). Scenery of the hard hydro-isolating plaster executed on the basis of base dry build mixture assumes application of the prepared compositions present at the market of build materials of Ukraine (for example, Ceresit CT-64).

Влияние технических лигносульфонатов на коррозию сварных швов в водоугольной суспензии

Hydrotransport of coal, iron ore, bauxite and other solid materials is known to be carried out through trunk pipelines. Hydrotransport of coal in the form of highly concentrated coal-water slurries (HCCWS) makes it possible to solve a whole range of problems from environmental ones to those when HCCWS are used as a fuel for energy boilers. The HCCWS combustion efficiency is determined by the concentration of the solid pulp phase and the particle size. The highest HCCWS combustion efficiency is observed when the mass concentration of the solid phase is 60--65 % and the particle size is up to 0.02 sm. In order to achieve stability of these slurries with the solid phase concentration, various additives are used to improve the rheological properties of coal-water slurries. In particular, such plasticizing agents as sodium tripolyphosphate, technical lignosulfonates, carbon-alkaline reagents and others are used. Plasticizing agents are known to change the rheological properties of coal-water slurries but the problems of corrosion activity of plasticizing agents are not well understood, especially with respect to welded joints of pipelines. Welded joints of slurry pipelines can be represented as macro-galvanic couples, in which the weld and base metal are electrodes of a galvanic element. The current magnitude of the macro-galvanic couple can be used to calculate the local corrosion value due to the work of the galvanic element of the base metal and the weld. The paper studies the effect of technical lignosulfonates (TLS) and TLS-based compositions in a coal-water slurry on the local currents of the base metal --- weld macro-galvanic couple made of 09G2S steel. Findings of research show that in the water-coal slurry the maximum inhibitory effect is observed when 0.75 % TLS + 0.25 % K2CrO4 (Na2CO3) is added to the slurry.

Modification of urea- and phenol-formaldehyde adhesives by natural fillers for the production of plywood

For the manufacture of plywood and chipboard are used urea-formaldehyde and phenol-formaldehyde hot curing adhesives. When it is necessary to reduce the content of toxic substances, to increase the strength and reliability of gluing, other properties of adhesive bonding heat urea and phenol-formaldehyde resins are modified. Urea-formaldehyde and phenol-formaldehyde resins were used for research. Urea-formaldehyde resin was modified with technical lignosulfonates with particle sizes of 0.01-0.2 mm, shungites with particle sizes of 0.2-0.8 mm, black shales with particle sizes of 0.005-0.2 mm and aluminosilicates with particle sizes of 0.2 - 0.8 mm. Phenol-formaldehyde resin was modified with pectol, black shales with particle sizes of 0.005-0.2, technical lignosulfonates with particle sizes of 0.01-0.2, and cold sludge from aluminum production with particle sizes of 0.01-0.2. A comparative analysis revealed that all the modifiers under study improve the physicochemical parameters of urea-formaldehyde and phenol-formaldehyde resins, increase the performance properties of glued materials from wood. Plywood was tested for shear strength over the adhesive layer and for the content of free formaldehyde in accordance with Russian standards. Modification of urea and phenol-formaldehyde resins with the proposed substances increases the strength of plywood, at the same time reducing the free formaldehyde content in products.

Опыт и эффективность применения пластифицированных закладочных смесей

Problem Statement (Relevance): Backfilling systems are widespread in the extraction of very valuable ores in difficult mining and geological conditions with regard to controlling rock pressure and maintaining the stability of the excavations, especially in the rockburst prone mines. Improving the composition of backfilling concrete is currently very relevant. In the production cost of mining ore with filling of a mined-out area, a share of backfilling work accounts for 20–25%. Reducing backfilling work costs is achieved by using various types of cement-free binders, involving various kinds of chemical additives and industrial wastes. The peculiarities of the use of chemical additives in the conditions of the Far North create a list of significant limitations, which make it highly complex to manufacture plasticized filling mixtures. Objectives: a main goal was to reduce the cost of one cubic meter of backfilling concrete. At the same time, the boundary conditions were minimum adjustments to the existing technology, formulation of compositions and productivity of mills. Methods Applied: the backfilling concrete cost reduction is achieved by introducing technical lignosulfonate, a chemical additive, which allows us to reduce the water demand of mixtures by 40–60 liters per cubic meter without changing the mobility of the mixture and lowering rheological characteristics. In its turn, a more optimal water/cement ratio makes it possible to increase the strength parameters, or with a decrease in binder consumption to reach the specified strength parameters. Originality: the paper presents the results of the studies on the application of plasticized additives in the production of backfilling concrete. Findings: Numerous laboratory and pilot industrial experiments at ALROSA mines (implemented in 2005) and the Polar Division of PJSC MMC Norilsk Nickel resulted in a decrease in portland cement consumption of up to 50 kg / m3. Practical Relevance: on the basis of positive results of pilot industrial tests, a technological regulation was developed for the revamping of the backfilling factories of Talnakh mines and the Polar Division of PJSC MMC Norilsk Nickel.

Efficient modified concrete for irrigation and drainage facilities construction

The paper describes scientific and technical prerequisites for the development of composition of and production method for hydrophobic complex modifier based on the industrial wastes, including technical lignosulfonates (TLS) as a plasticizing ingredient; oil and fat tar as hydrophobic ingredient; and saponified wood pitch (SWP) as air entraining ingredient. The purpose of the presented studies was the development of an efficient modified concrete composition for construction of irrigation and drainage facilities construction by using a complex hydrophobic modifier. Experimental studies were carried out on concrete samples made of reference and test compositions in the laboratory of the “Building Materials” Department of the National Research Moscow State University of Civil Engineering. Comprehensive studies showed that the use of hydrophobic modifier allows obtaining concrete with water bleeding ratio reduced by 35–40%; reducing the concrete capillary suction and water absorption by 3 times; and increasing water penetration pressure (W8 and more), in comparison with concrete without additives. The developed complex hydrophobic modifier increases the strength by 12-18% and reduces shrinkage strain of concrete by 7.5% in comparison with the control composition without the modifier.

The effect of silver salts and lignosulfonates in the synthesis of lignosulfonate-stabilized silver nanoparticles

Water-soluble lignin derivatives – technical lignosulfonates (LS) – were used as reducing and stabilizing agents for a simple synthesis of silver nanoparticles (LS-AgNPs) in aqueous solution at room temperature during the reaction with silver salt. Three salts were used as the metal precursor: AgClO4, AgBF4 and CH3C6H4SO3Ag. The obtained silver colloids were analyzed by UV–Vis spectrophotometry, particle size distribution (NIBS method), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Both the origin of the biomacromolecule and the type of silver salt contribute to the final size and shape of the LS-AgNPs. Therefore the selection of different reagents can be used to control the AgNPs size. As a possible application, the obtained silver particles were studied for their catalytic activity in the reduction of three dyes – C.I. Basic Blue 9 (methylene blue), C.I. Basic Violet 10 (rhodamine B) and C.I. Basic Orange 14 (acridine orange) – by sodium borohydride.