New approach for inert filtering media modification by using precipitates of deironing filters for underground water treatment

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BACKGROUND The volumes of discharged spent plating electrolytes comprise ≈2–3% of the total amount of wastewater from galvanic production. However, the concentration of heavy metal ions they contain is 100–150‐fold higher than in rinsing waters. The periodic nature of such discharges leads to a disruption in the operation of treatment facilities. At the same time, heavy metals could be separated as pigments. RESULTS The article presents the results of studies of the effect of brighteners included in the composition of spent zinc (Zn) plating electrolytes on the composition and structure of the resulting white pigments. The results confirmed the possibility of obtaining white pigments from spent Zn plating electrolytes. It was found that during the deposition of Zn(II) ions from the spent ammonium chloride (NH4Cl) Zn plating electrolytes with sodium phosphate, zinc phosphate predominantly is formed. It was found that the presence of brighteners in the spent NH4Cl Zn plating electrolytes practically did not affect the pH and the degree of deposition of Zn (II) ions, as well as the whiteness of the resulting pigments. CONCLUSION The presence of iron (Fe) ions in the spent zinc plating electrolytes leads to a decrease in the whiteness of the resulting precipitates; however, pigments of the required whiteness can be obtained with contents of Fe(III) of ≤170 mg L−1 and Fe(II) ≤1000 mg L−1. © 2021 Society of Chemical Industry (SCI).

Section: Introductionmentioning

confidence: 99%

“…They also arecharacterized by a wide range of operating current densities at a cathode current output of metal close to 100%, and can be used to cover details of various configurations. In this regard, NH 4 Cl electrolytes for Zn plating were chosen as the object of study in this work.…”

Section: Introductionmentioning

confidence: 99%

Pigments from spent ammonium chloride zinc plating electrolytes

Zalyhina

Cheprasova

Romanovski

2021

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“…Recycling of waste in resource production processes is one of the priority problems to be solved in the area of sustainable manufacturing. [1][2][3] This makes it possible not only to reduce the generation of excess waste, but also to organize the production of new sustainable materials [4][5][6][7][8][9] in accordance with improved methods that also meet modern requirements. Spent sulfuric acid is formed in various technological processes.…”

Section: Introductionmentioning

confidence: 99%

“…The resulting filtrate will contain soluble salts obtained in the synthesis process due to impurities. These ions are Na + , K + , Mg 2+ and SO 4 2− , which have potential for use in fertilizers for plants. [23][24][25] Sodium absorption is highly dependent on the plant 26 because it regulates the transport of carbohydrates in the plant and increases winter hardiness.…”

Section: Introductionmentioning

confidence: 99%

Structurally controlled synthesis of synthetic gypsum derived from industrial wastes: sustainable approach

Kamarou

Korob

Romanovski

2021

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BACKGROUND: The article demonstrates the possibility of processing spent sulfuric acid and limestone waste into high-quality synthetic calcium sulfate dihydrate. RESULTS: A comprehensive technological scheme for the production of synthetic gypsum from industrial waste was proposed. Mathematical models of the main technological stages were obtained. In the process of acid processing, at the stage of separating gypsum from the mother liquor, a filtrate was formed containing ions such as Na + , K + , Mg 2+ and SO 4 2− , which are some of the main ions necessary for plant growth. A positive effect was found when using the filtrate as fertilizer.CONCLUSIONS: Optimal values of synthesis parameters that allow one to obtain crystals of the maximum size were determined. A positive effect when using the filtrate as fertilizer was found. These results mean that it is possible to obtain a technology for gypsum with a closed production cycle (waste-free technology) derived from waste limestone and spent sulfuric acid.

“…This provides an efficient solution within the principles of a circular economy. Together with new approaches to synthesis, 3 the use of waste helps solve several environmental protection issues, along with having positive economic and social effects.…”

Section: Introductionmentioning

confidence: 99%

Low‐energy technology for producing anhydrite in the CaCO₃–H₂SO₄–H₂O system derived from industrial wastes

Kamarou

Korob

Hil

et al. 2021

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BACKGROUND: A high-quality anhydrite binder could be produced due to the exergy of sulfuric acid in the CaCO 3 -H 2 SO 4 -H 2 O system derived from industrial wastes. Waste of sulfuric acid derived from the production of heat-resistant fibers and wastes of limestone that was formed on the metallurgical enterprise were used for the synthesis of anhydrite. Such a product is safe from an environmental point of view and has many advantages, both operational and economic, over standard gypsum binders.RESULTS: The optimal technological parameters have been established and a technological scheme for producing anhydrite excluding the stage of calcium sulfate dihydrate formation has been proposed. Anhydrite production in the CaCO 3 -H 2 SO 4 -H 2 O system, due to the exergy of sulfuric acid, is a promising technology to replace the traditional thermal technology for producing anhydrite. This technology can reduce fuel costs because the required synthesis temperature is 95-105°С, instead of 800-1000°С in the traditional one, and this significantly reduces the cost of manufactured products. CONCLUSION:The maximum yield of synthetic anhydrite was provided by a limestone suspension taken in a stoichiometric amount. This neutralizing agent makes it possible to obtain particles of a prismatic shape, the size of which is generally more than 20 ∼m.