Sulfuric Acid Research Articles

Effects of Sulfuric and Citric Acid for Slurry Acidification on Winter Wheat Yield, N- and S-Balance

Slurry can be acidified to reduce ammonia emissions during slurry application. As considerable quantities of sulfuric acid are required, a lot of S is applied to the soil. The aim of this study was to investigate whether the additional S supply from sulfuric acid has a positive effect on plant growth by comparing sulfuric acid with citric acid. Furthermore, the fate of the S supplied in excess to the plant requirement was investigated. A field experiment was set up with slurry acidified with sulfuric and citric acid. Yield, N and S concentrations of plant and soil samples on three dates during the growing season were measured. At harvest, grain yield was determined, and the harvested crop was analyzed for N and S concentration. After harvest, soil samples were taken on two further dates and soil mineral N (Nmin) and S (Smin) concentrations were measured. At harvest grain yield and N and S uptake by the grain were the same for the sulfuric and citric acid treatments, but the sulfuric acid treatment had significantly higher Smin levels on all dates. After harvest, Smin was then leached via the 30-60 cm layer into the 60-90 cm layer. The very high S supply from the sulfuric acid used to acidify the slurry did not affect the yield nor the N and S uptake of the wheat. S that enters the soil in excess of the plant requirements is transferred with the leachate to deeper soil layers.

Twenty-eight days later: The recovery of DNA from human remains submerged in aggressive household chemicals.

Aggressive chemicals intended for cleaning pools or unclogging drains contain high concentrations of dangerous compounds, leading to their nefarious use in dissolving human remains in some criminal cases. The use of these readily accessible household cleaners to destroy human remains and hide evidence of a crime presents a considerable challenge for human identification. However, research on the success of recovering DNA from such remains is limited. Therefore, we investigated the effects of submerging partial human remains (including whole heads, forearms, and hands) in five different household products: bleach, Rid-X® septic treatment, lye drain opener, sulfuric acid drain opener, and muriatic acid (hydrochloric acid) pool cleaner. We evaluated the impact of each chemical, focusing on visual changes, DNA recovery, and the potential for successful human identification through traditional STR or mitochondrial DNA analyses. Exposure to all chemicals altered the appearance of the remains, but DNA recovery was still possible across various time periods, up to 28 days. Human remains exposed to bleach, Rid-X®, and lye produced full STR profiles after 4 weeks. Sulfuric acid shortened this time to 3 weeks, while hydrochloric acid, the most damaging chemical, limitedfull STR profile recovery to just the first 3 days of exposure. This study demonstrates that although differences in the rate of damage occur depending on the amount of tissue introduced, volume of chemical used, and the specific chemical of choice, DNA-based human identification of remains treated with everyday household cleaners is likely, particularly if bone fragments are recovered.

Thermodynamic Modeling and Research for Processing Complex Concentrate Blends in Custom Copper Smelters for Maximum Revenue

Custom copper smelters, which are dependent on purchased concentrates, are facing increasing economic pressures amid falling treatment and refining fees. With the declining availability of high-grade, low-impurity concentrates, copper demand is expected to surge to support the transition to renewable energy. This study, which is based on recent observations of Chinese custom smelters, examines their strategies to address the challenge of purchasing concentrates at record-low treatment and refining charges. By investing in slag flotation technology, smelters can enhance copper, gold, and silver recovery. By blending high-grade and low-grade concentrates, they can capitalize on the gap between the recoverable and payable metals, which are often referred to as “free metals”, while also benefiting from byproducts, mainly sulfuric acid. While this approach offers economic opportunities, it introduces operational complexities. To mitigate these, laboratory testing, combined with advanced digital predictive tools based on thermodynamics, is crucial. This study demonstrates the use of thermodynamic models supported by experimental work for analyzing furnace operations. FactSage® software and a custom database are employed to define the operating window of two common flowsheets: (1) flash smelting + flash converting and (2) bottom-blown smelting + bottom-blowing converting.

Precipitation and flotation concentration of neodymium, erbium, and thulium ions by alkylbenzenesulfonic acid

The possibility of using the commercially produced anionic surfactant alkylbenzenesulfonic acid for the precipitation and flotation extraction of neodymium(III), erbium(III), and thulium(III) ions was investigated. The effects of concentration and ratio of reacting components, content of sulfuric acid, and sodium hydroxide on the precipitation efficiency of metal ions were considered. The composition of the resulting compounds was determined and their conditional solubility products were calculated. Flotation conditions for metal ions with alkylbenzenesulfonic acid were optimized.

Photoluminescence and Dye Adsorption Mechanism of Dehydrated Carbon Quantum Dots

The role of oxygen-based functional groups in the photoluminescence of dehydrated carbon dots (DCs) and the adsorption mechanism of dye molecules onto the surface of DC is investigated. DC were prepared from orange peel for the first time via the chemical dehydration effect of sulfuric and phosphoric acid at 180 oC. We compared the emission spectra of DCs in different solvents in great detail. The solvatochromism of DC in different solvents is discussed. The role of oxygen-based functional groups in the light emission process is examined. Adsorption of methylene blue (MB) on the surface of DC was studied at different contact times, pH, concentrations, and temperatures. In this work, we used Langmuir and Freundlich adsorption models for the analysis. Sorption kinetic data were found to fit well with the pseudo-second-order model. Our results also showed increased MB adsorption capability with temperature. The results are essential for the application of CQDs, such as in wastewater treatment. Keywords: Photoluminescence; Adsorption; Solvatochromism; Carbon dots; Methylene blue (MB).

Evaluation of the Antibacterial and Cell Culture Properties of Anodic Porous Alumina Prepared in Concentrated H2SO4.

The antibacterial activity of anodic porous alumina (APA) prepared using phosphoric, oxalic, and sulfuric acids was tested, and it was found that APA prepared using sulfuric acid had the highest antibacterial activity against Staphylococcus aureus and Escherichia coli. In addition, the results of the antibacterial test using APA prepared with different concentrations of sulfuric acid showed that APA prepared in concentrated sulfuric acid exhibited significantly higher antibacterial activity. APA formed in concentrated sulfuric acid also showed excellent antibacterial activity even at a high culture medium concentration, at which bacterial cells tend to multiply easily. Trace amounts of Al and S that leached out to the culture medium from APA prepared in concentrated sulfuric acid did not affect the antibacterial activity of APA, indicating that the APA surface exhibits excellent antibacterial activity. It was shown that the surface of APA prepared in concentrated sulfuric acid had excellent culture properties for fibroblasts while exhibiting antibacterial activity. APA prepared in concentrated sulfuric acid can be used in various applications that require excellent antibacterial activity as well as on surfaces that suppress bacterial growth and selectively cultivate target cells.

Effect of acetic acid concentration on obtaining cellulose acetate from oil palm mesocarp fibers (Elaeis guineensis Jacq.)

This work aimed to produce cellulose acetate from the mesocarp fibers of palm oil treated with sodium hydroxide (MFA) and bleached with sodium chlorite. Cellulose acetate was obtained from the different materials by homogeneous acetylation in the mass proportions of: 1:5, 1:10 and 1:15 (acetic acid), 1:15 (acetic anhydride) and 1:0.1 (sulfuric acid). The degree of substitution was determined by chemical methods and by 1H-NMR. The cellulose acetate obtained from the combination of alkaline treatments followed by bleaching showed degree of substitution of 2.81 (CAAB5), 3.02 (CAAB10) and 3.07 (CAAB15), corresponding to yield values (w/w) of 50.45%, 65.5% and 97.21%. Based on the analysis of the results, we can say that the amount of acetic acid and the type of treatment used in the fibers of the mesocarp of oil palm directly influenced the quality and yield of cellulose acetate, with CAAB15 being the best reaction condition.

Influence of sand type on acid resistance and capillary absorption capacity

This study aims to investigate the effect of binary and ternary combinations of river sand (RS), crushed sand (CS) and dune sand (DS) on the physical and mechanical performance of concrete subjected to acidic curing environments. The RS was replaced by CS and DS in different mass proportions. The five concrete mixtures M21(RS), M04(0.6CS + 0.4DS), M10(0.2RS + 0.6CS + 0.2DS), M15(0.4RS + 0.6CS) and M16(0.6RS + 0.4DS) were prepared. The sorptivity was evaluated by measuring the sorptivity coefficient (S, cm*s-0.5) after 28 days of submersion in distilled water. Concrete specimens were submersed in distilled water, 5% sulfuric acid (H2SO4), and 5% hydrochloric acid (HCl) for up to 180 days in order to test their acid resistance. Visual inspection, changes in mass and changes in compressive strength were used to evaluate the specimens' resistance to acid attack. The results indicated that replacing RS with CS led to an increase in sorptivity, while replacing RS with DS resulted in a decrease. When both CS and DS were used in place of RS, acid resistance in 5% HCl solution decreased. In 5% H2SO4 solution, substituting RS with CS reduced mass loss, but replacing RS with both CS and DS weakened the concrete's compressive strength.

Sulfuric Acid-Driven Nucleation Enhanced by Amines from Ethanol Gasoline Vehicle Emission: Machine Learning Model and Mechanistic Study.

The sulfuric acid (SA)-amine nucleation mechanism gained increasing attention due to its important role in atmospheric secondary particle formation. However, the intrinsic enhancing potential (IEP) of various amines remains largely unknown, restraining the assessment on the role of the SA-amines mechanism at various locations. Herein, machine learning (ML) models were constructed for high-throughput prediction of IEP of amines, and the nucleation mechanism of specific amines with high IEP was investigated. The formation free energy (ΔG) of SA-amines dimer clusters, a key parameter for assessing IEP, was calculated for 58 amines. Based on the calculated ΔG values, seven ML models were constructed and the best one was further utilized to predict the ΔG values of the remaining 153 amines. Diethylamine (DEA), mainly emitted from ethanol gasoline vehicles, was found to be one of the amines with the highest IEP for SA-driven nucleation. By studying larger SA-DEA clusters, it was found that the nucleation rate of DEA with SA is 3-7 times higher than that of dimethylamine, a well-known key base for SA-driven nucleation. The study provides a powerful tool for evaluating the actual role of amines on SA-driven nucleation and revealed that the mechanism could be particularly important in areas where ethanol gasoline vehicles are widely used.

A Study on the Treatment of Sodium Sulfate Waste Solution by Constant Current Control Bipolar Membrane Electrodialysis

As environmental pollution has intensified, the importance of recycling spent lithium-ion batteries (LIBs) has significantly increased. Valuable metals contained in LIBs are typically recovered through processes such as leaching, precipitation, and solvent extraction. However, these recycling processes require large amounts of sulfuric acid and caustic soda, resulting in the generation of significant volumes of Na<sub>2</sub>SO<sub>4</sub> waste solution. In order to solve this problem, recent research has focused on using bipolar membrane electrodialysis (BMED) technology to split Na<sub>2</sub>SO<sub>4</sub> and simultaneously recover H<sub>2</sub>SO<sub>4</sub> and NaOH. This study investigated the process of recovering H<sub>2</sub>SO<sub>4</sub> and NaOH from Na<sub>2</sub>SO<sub>4</sub> solution using BMED in a threecompartment cell under constant current conditions. The study evaluated the effects of current density, initial Na<sub>2</sub>SO<sub>4</sub> concentration, and initial H<sub>2</sub>SO<sub>4</sub> and NaOH concentrations. Recovery of H<sub>2</sub>SO<sub>4</sub> and NaOH, current efficiency, energy consumption, and process time were analyzed to determine optimal conditions. Under optimal conditions (1.30 M Na<sub>2</sub>SO<sub>4</sub> solution at 360 A/m²), the recovery of H<sub>2</sub>SO<sub>4</sub> and NaOH were 77.35% and 75.18%, respectively. Energy consumption was 1.43 kWh/kg, with current efficiencies for the acid and base of 51.1% and 49.7%, respectively.

Enhancing the Pseudocapacitive Energy Storage of Coordination Polymers by Artificially Constructed Defective Sites Anchoring Redox-Active Species.

Coordination polymers (CPs) have emerged as potential energy storage materials for supercapacitors due to their tunable chemical composition, structural diversity, and multielectron redox-active sites. However, besides poor cycling stability, the practical application of dense CPs in supercapacitors is generally limited by low specific capacitance and high resistance, which are caused by their low specific surface area and dense frameworks, resulting in insufficient redox reactions of metal sites and poor ion diffusion, respectively. Here, we synthesize a new dense CP {CP-1: [Ce(obb)(HCOO)]∞} via self-assembly of the Ce cation and 4,4'-oxidibenzoate (obb2-). The specific capacitance of CP-1 increases by 156.7 times, and its lifetime after charge-discharge for 5000 cycles is elevated from 62 to 86.7%; meanwhile, the resistance of the positive electrode is reduced from 1.05 to 0.73 Ω through this defect engineering strategy (DES), i.e., cyclic voltammetry sweep in a sulfuric acid electrolyte to artificially construct defects for anchoring the redox-active species (ferricyanide anions). To investigate the universality of this strategy, we have applied it to the other two previously reported CPs {CP-2: [Ce4(obb)6(H2O)9·(H2O)]∞ and CP-3: [Ce2(obb)3(OH)(H2O)(DMF)]∞}, which are also obtained by self-assembly of the Ce cation and obb2- ligand. By comparing the electrochemical performances of the three pristine CPs and their corresponding defect-engineered CPs obtained through the DES, we have found that (i) this strategy is effective in enhancing the electrochemical performances for all three CP materials and (ii) the effect of this strategy on improving the electrochemical performance of CP-1 with a three-dimensional dense network is better than that of CP-3 with a layered structure, and both are better than that of CP-2 with small pores. This work demonstrates a new effective universal strategy for boosting the electrochemical performances of CPs, thus advancing their application in the energy storage field.

Obtaining Cellulose Nanocrystals in a Medium of Primary Monohydric Alcohols

The lack of a universal method for isolating cellulose nanocrystals (CNCs) has encouraged researchers to look for new methods and approaches as alternatives to traditional sulfuric acid hydrolysis. Acid alcoholysis has long been actively used in cellulose depolymerization processes to obtain a variety of alkyl glycosides and further alcoholysis products. In the present article, the authors continue their earlier research on the synthesis of CNCs in the presence of a sulfuric acid catalyst in an alcoholic environment. In this work, CNCs were obtained from sulfate-bleached pulp in a medium of primary monohydric alcohols (СnH2n+1OH, n = 5–8). A maximum CNC yield of 60 % was achieved with pentanol-1 at a sulfuric acid concentration of 50 %. The work revealed that the alcohols studied can be ranked in descending order based on both the acid concentration corresponding to the maximum CNC yield and the yield itself, as follows: pentanol-1, hexanol‑1, heptanol-1, and octanol-1. For octanol-1 the maximum CNC yield was 20 % at an acid concentration of 40 %. The physicochemical properties of the isolated CNCs were studied. No surface alkylation of the synthesized CNCs was found to occur during cellulose treatment in the media of the alcohols studied, as the properties of the CNCs, in general, were similar to those of CNCs obtained by standard sulfuric acid hydrolysis. This study broadens the scope of alternative methods to traditional sulfuric acid hydrolysis, and is likely to appeal to researchers engaged in developing novel approaches for CNC extraction.

Helical magnetism in poly(aniline-co-ferrocene): structure and magnetism.

This study reports the synthesis and characterisation of a ferrocene-based conjugated polymer and a chiral composite. The precursor copolymer was synthesised from 1,3-phenylenediamine and 1,1'-dibromoferrocene via Buchwald-Hartwig polycondensation. This polymerisation process increased the effective conjugation length and led to magnetic spin interactions along the main chain, resulting in a ground triplet spin state at 25 °C. Furthermore, the polymer was oxidised with m-chloroperoxybenzoic acid and doped with sulfuric acid. A chiral polymer blend was also prepared by combining the copolymer with hydroxypropyl cellulose to form helical polymer liquid crystals. The physical properties of these polymers were analysed using superconducting quantum interference devices, optical spectroscopy, electron spin resonance, and X-ray fluorescence spectroscopy. The resulting polymer blend exhibits helical magnetism. This approach to fabricating a chiral magnetic material from an achiral polymer via supramolecular chirality introduces a new method for preparing chiral magnets.

Sulphotransferase-mediated toxification of chemicals in mouse models: effect of knockout or humanisation of SULT genes.

Cytosolic sulphotransferase (SULT) enzymes catalyse reactions involved in xenobiotic elimination and hormone regulation. However, SULTs can also generate electrophilic reactive intermediates from certain substrates, including the activation of carcinogens. Here, we review toxicological studies of mouse strains with SULT status altered by genetic modification. Knockout mouse strains have been constructed for the enzymes Sult1a1, 1d1, 1e1, 2b1 and 4a1. In addition, transgenic strains are available for human SULT1A1/2. Among SULT knockout mouse strains, reduced fertility (Sult1e1) and early postnatal death (Sult4a1) were observed. In contrast, Sult1a1 or Sult1d1 knockouts and SULT1A1/2 transgenics were healthy and showed no obvious deficiencies. These strains were used in toxicological studies with 13 chemicals. Manipulation of the SULT system altered dramatically the adverse effects of many compounds; thus, very large differences in levels of DNA adducts formed in the liver or other tissues were seen with some chemicals - up to 99.2% decreases in knockouts and 83-fold increases in SULT1A1/2 transgenics. In many cases, these changes were restricted to the tissues in which the corresponding enzymes are expressed, arguing for local activation. However, with some compounds, the kidney was an important target tissue, due to the active transfer to that organ, via the circulation, of reactive sulphuric acid esters.

New particle formation from isoprene under upper-tropospheric conditions

Aircraft observations have revealed ubiquitous new particle formation in the tropical upper troposphere over the Amazon1,2 and the Atlantic and Pacific oceans3,4. Although the vapours involved remain unknown, recent satellite observations have revealed surprisingly high night-time isoprene mixing ratios of up to 1 part per billion by volume (ppbv) in the tropical upper troposphere5. Here, in experiments performed with the CERN CLOUD (Cosmics Leaving Outdoor Droplets) chamber, we report new particle formation initiated by the reaction of hydroxyl radicals with isoprene at upper-tropospheric temperatures of −30 °C and −50 °C. We find that isoprene-oxygenated organic molecules (IP-OOM) nucleate at concentrations found in the upper troposphere, without requiring any more vapours. Moreover, the nucleation rates are enhanced 100-fold by extremely low concentrations of sulfuric acid or iodine oxoacids above 105 cm−3, reaching rates around 30 cm−3 s−1 at acid concentrations of 106 cm−3. Our measurements show that nucleation involves sequential addition of IP-OOM, together with zero or one acid molecule in the embryonic molecular clusters. IP-OOM also drive rapid particle growth at 3–60 nm h−1. We find that rapid nucleation and growth rates persist in the presence of NOx at upper-tropospheric concentrations from lightning. Our laboratory measurements show that isoprene emitted by rainforests may drive rapid new particle formation in extensive regions of the tropical upper troposphere1,2, resulting in tens of thousands of particles per cubic centimetre.

Sustainable Techniques for Overcoming Seed Dormancy in Flamboyant (Delonix regia)

Aims: The aim of this study is to evaluate methods of overcoming the dormancy of Delonix regia seeds, with an emphasis on sustainable techniques. Study Design: The experimental design was entirely randomized, with five replicates of 20 seeds. Place and Duration of Study: The study was conducted on the premises of the Instituto Federal do Tocantins, Câmpus Avançado Formoso do Araguaia, located in the municipality of Formoso do Araguaia, in the state of Tocantins, Brazil. Between September 2024 and October 2024. Methodology: The seeds were subjected to the following treatments: T1, untreated seeds (control); T2, chemical scarification with sulfuric acid for 3 minutes; T3, chemical scarification with sulfuric acid for 5 minutes; T4, immersion in water at 80°C for 3 minutes, followed by cooling to room temperature; T5, immersion in water at 80°C for 5 minutes, followed by cooling to room temperature; and T6, immersion in water at 80°C for 10 minutes, followed by cooling to room temperature. The analyses carried out included seedling emergence, the emergence speed index, the average emergence time and the emergence speed coefficient. The experiment followed a completely randomized design with five replicates of 20 seeds each. The data were subjected to tests for normality and homoscedasticity, followed by analysis of variance (ANOVA) using the F-test, and the means were compared using Tukey’s test at a 5% significance level. Results: The results of this study indicated that heat treatments with immersion in water at 80°C for 5 minutes (T5) were the most effective in overcoming the dormancy of Delonix regia seeds. This method resulted in the highest emergence rates and the highest emergence speed indexes (ESI), highlighting its potential as a sustainable and efficient alternative to chemical treatments. Conclusion: The results of this study indicated that heat treatment with immersion in water at 80°C for 5 minutes was the most effective in overcoming the dormancy of Delonix regia seeds.

Venus cloud catcher as a proof of concept aerosol collection instrument

We report on the proof-of-concept of a low-mass, low-power method for collecting micron-sized sulfuric acid aerosols in bulk from the atmosphere of Venus. The collection method uses four wired meshes in a sandwich structure with a deposition area of 225 cm2. It operates in two modes: passive and electrostatic. During passive operation, aerosols are gathered on the deposition surface by aerodynamic force. During electrostatic operation, a tungsten needle discharges a high voltage of − 10 kV at the front of the grounded mesh structure. The discharge ionizes aerosols and attracts them to the mesh by Coulomb forces, resulting in improved efficiency and tentative attraction of submicron aerosols. We describe the instrument construction and testing in the laboratory under controlled conditions with aerosols composed of 25%, 50%, 70%, 80%, 90% and 98%* concentration by volume of sulfuric acid, the rest water. We demonstrated the following: (i) both modes of operation can collect the entire range of sulfuric acid solutions; (ii) the collection efficiency increases steadily (from a few percent for water to over 40% for concentrated sulfuric acid) with the increased concentration of sulfuric acid solution in water in both modes; (iii) the relative improvement in the collection of the electrostatic mode decreases as the sulfuric acid concentration increases. We also demonstrated the operation of the instrument in the field, cloud particle collection on Mt. Washington, NH, and crater-rim fumaroles’ particle collection on Kīlauea volcano, HI. The collection rate in the field is wind-speed dependent, and we observed collection rates around 0.1 ml in low wind environments (1–2 m), and around 1 ml in stronger wind (7–9 m).

Anodization of Aluminum in a Sodium Hydroxide Solution: Effect of pH on Chemical Dissolution

Abstract The chemical dissolution of anodic alumina film was investigated using the re-anodization technique. The formation of thick oxide films in an alkaline electrolyte is thought to be difficult to achieve due to the high pH value and high solubility of anodic alumina. The dissolution rate of anodic film was found to be strongly affected by the pH of the solution used for chemical dissolution; the film dissolved significantly faster in a sodium hydroxide solution having a high pH of 13.11 than in acidic solutions commonly used for anodization, such as sulfuric acid (pH 0.98) and phosphoric acid (pH 1.54). Nevertheless, the addition of glycerol to the sodium hydroxide solution effectively suppressed the chemical dissolution of the anodic film. The change in solubility of the anodic alumina film in solution was greatly affected by the change in the dissociation of the solute in solution. The results demonstrated that oxide films more than 10 μm thick were produced in an alkaline electrolyte by adding glycerol to the solution. The suppression of the chemical dissolution of alumina by the addition of alcohol has thus been shown to occur not only in acid solutions but also in alkaline solutions.

COMPLEX TECHNOLOGY OF THE CLEANING OF AGGLOMERATION GASES FROM DUST AND HARMFUL GASES WITH OBTAINING A GOOD PRODUCT

The purpose of the work is to improve the design of the dust-catching device of the sintering machine, to increase the efficiency of catching charged dust particles in laminar layers near the precipitating elements, the configuration and location of the elements of the precipitating elements, to establish the dependence of the effective (calculated) drift speed of charged dispersed particles on the speed of the medium being cleaned, with classical the process of electrogas purification and the combined flow of gases in electrofilters. It was established that the combined movement of gases in a modular unit ensures the charging of the entire population of dust particles to the limit values ​​by organizing a highly turbulent flow and keeping dust particles in the zones with the greatest tension in the corona charge covers, as well as effective trapping of charged dust particles in laminar layers near the precipitating elements . Mathematical modeling of the deposition block was carried out in order to optimize the configuration. The main dependences of the number and mutual location of precipitating elements to ensure maximum dust deposition were established. Studies of gas medium velocity spectra in models of new electrostatic precipitators have been carried out. The optimal live cross-sections of the aerodynamic partitions are determined to ensure favorable conditions for charging suspended particles and uniform distribution of the cleaned flow through the catching holes. The MV-2 modular type electric gas purification device with a capacity of 30 thousand nm3/h has been developed, based on innovative developments in the field of KEIT (combined electro-ion gas purification technology) in the field of conversion and control of cascade energy and aerodynamics of turbulent and laminar flows during inertial deposition dispersed suspension of flue gases. An apparatus for cleaning gases from a sinter machine with a capacity of up to 400,000 nm3/h is proposed. with an efficiency of 99 %, for replacing existing equipment (multicyclones). "MV-2JS" electric device was developed. This is a plasma-catalytic reactor, which allows you to produce the necessary amount of ozone in a low-cost way to oxidize the harmful components (SO2, NOx, CO) of the outgoing gases. The use of this device allows, in addition to the cleaning of flue gases from harmful gas impurities, to obtain commercial products (fertilizers, gypsum, sulfuric acid, etc.) at the output and to completely get rid of solid and liquid waste during gas desulfurization.

Stepwise extraction of zinc, indium and lead from secondary zinc oxide dusts experimental study

Secondary zinc oxide dust is rich in high-grade metals such as Zn, In, Pb, and Ga, and in the face of the depletion of ore resources at home and abroad, it is of great significance to seek an efficient process to realize the full resource recovery of valuable metals in secondary zinc oxide dust. In this study, on the basis of the thermodynamic analysis of the wet treatment process, three wet treatment methods, namely “low acid leaching”, “high acid leaching” and “chlorination leaching”, were used to explore the suitable parameters for stepwise extraction of Zn, In and Pb metals. The results showed that the three wet treatment methods could effectively extract the corresponding main elements, and the optimal leaching rates of Zn, In and Pb were 73, 90 and 94%, respectively. Thermodynamic analysis shows that under ideal conditions, the “cascade separation” of some or all metals can be theoretically achieved by using a suitable leaching solvent for zinc oxide dust. The concentration of sulfuric acid, the ratio of liquid solid volume to mass and temperature had great effects on the leaching rate of Zn and In, and the leaching rate of Zn and In also increased with the increase of the values of the three experimental parameters, which was positively correlated. The leaching rate of Pb will increase with the increase of sulfuric acid concentration, but when the pH of the solution system is < 2, Pb will form PbSO4 precipitate, which inhibits the leaching ability of Pb. In the chlorinated leaching system with “ammonium chloride + hydrochloric acid” as the leaching solvent, the excess Cl− and Pb2+ fully coordinated to promote the efficient leaching of Pb metal, and the initial pH value of the solution had a great influence on the Leaching Rate of Pb. The multi-stage combined wet treatment process is an effective solution to realize the full quantitative recovery of valuable elements in Secondary zinc oxide dust, In this paper, the suitable process conditions for stepwise extraction of Zn, In and Pb metals were obtained through wet treatment experiments, and the cascade separation of metals in zinc oxide dust was preliminarily realized, which provided an important idea for the efficient utilization of metallurgical dust and sludge solid wastes, and at the same time provided theoretical support for the industrial practice of recycling valuable elements in metallurgical dust.