Journal of Material Cycles and Waste Management
·
2024
·
IF 2.7
Zheng Zhengqiang,Weng Changzhou,Kang Zeyu,Zhong Minhua,Yu Changyong,Lin Zhang,Liu Weizhen
In China, large amounts of industrial byproduct gypsum (IBG) end up as waste and excessive stockpiling due to its low whiteness and high impurity content. In this study, two typical IBG including phosphogypsum (PG) and flue gas desulfurization gypsum (FGDG) were the research object. The impurities removal and the whiteness improvement by the tandem pyro-hydro process were investigated. Species of impurities, mechanism of whiteness improvement and the evolution of the gypsum phase during the tandem process were revealed. The results indicate that the impurities responsible for the poor whiteness of IBG included organic matter, carbon particles, and silicates. The temperature of the pyro process is the critical factor. The IBG is calcinated at 400–500 °C to fully remove organic matter and carbon particles, while decompose silicates to silica. Following, in the hydro step, the calcined IBG was treated with dilute sulfuric acid (0.2–1.0 M) to remove ion impurities such as Fe(III), the higher temperature and higher acidity are favorable to the production of valuable CaSO 4 . After treatment, the whiteness of IBG was improved from below 40% to above 80%, and the soluble impurity content can meet the standards. Moreover, both PG and FGDG products exhibited a compressive strength exceeding 10.0 MPa of curing for 7 d. This work provides theoretical guidance to promote the resource utilization of IBG, especially as plastering materials after purification and whitening. Graphical Abstract
研究领域:
材料科学
·
环境工程
✓ 已验证
DOI
高影响因子
MINERALS ENGINEERING
·
2024
·
IF 4.9
Shengzong Lan,Liuyang Dong,Peilun Shen,Haoran Su,Zhengchang Shen,Dianwen Liu
A large amount of the industrial byproduct gypsum can harm the environment, so developing an innovative approach for the utilization of gypsum is highly important. In this study, gypsum was employed to increase the flotation separation efficiency of apatite from calcite. The micro-flotation test revealed that sodium oleate could not separate the two minerals without a depressant. At pH 9, following the incorporation of gypsum, apatite achieved a recovery of 83.22 %, which was 51.49 % greater than that of calcite. The artificial mixed mineral test yielded a mixed concentrate with a P 2 O 5 recovery of 72.71 % and a grade of 25.88 %. Mineral surface properties were analyzed, revealing that gypsum enhanced the hydrophilicity of the calcite surface and inhibited NaOL adsorption on calcite but had a minimal impact on apatite. Ca 2+ in the slurry facilitated SO 4 2– adsorption on the calcite surface. X-ray photoelectron spectroscopy results indicated that phosphate species on the apatite surface could adsorb Ca 2+ from the solution, creating active sites for sodium oleate. Additionally, a higher concentration of S was observed on the calcite surface, suggesting that the adsorption capacity of gypsum dissolved in the slurry is greater on the surface of calcite. Surface morphology analysis revealed selective gypsum dissolved components adsorption on calcite rather than apatite, primarily within the 8–30 nm range, exhibiting uniform spot adsorption. These findings demonstrate the potential of gypsum as an inorganic depressant for calcite from various sources, enabling the flotation separation of apatite from calcite and thus providing a theoretical basis for the resource utilization of gypsum solid waste.
研究领域:
矿物加工工程
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2023
·
IF 7.4
Xiaosong Ma,Linzhen Tan,Yuanjing Lu,Wu Yao,Yongqi Wei
A large number of waste gypsum was reused of low-value or landfilled which caused serious waste of resources. In this study, a high value-added recycling scheme for waste building gypsum to synthesize a 3D printable material with high-precision was designed. The α-hemihydrate gypsum (α-HH) was synthesized from waste plasterboard by the salt solution hydrothermal method. A synergistic optimization strategy was proposed involving the effect of sodium succinate and pH on the morphology and mechanical strength of α-HH. The properties of recycled α-HH were modified to meet the requirements of 3D printing , including fluidity, setting time and green strength. When the modifier dosage is 0.05 wt% and the pH is 5, the best morphology of α-HH crystals with an average aspect ratio of 1.07 (length of 10 μm) are synthesized. The converted product has close interlocking and intergrowth after hydration, which exhibits excellent mechanical strength (25.5 MPa). The 3D printing materials prepared by the composite modification of recycled α gypsum powder has proven to achieve good printable. The print errors smaller than 4% for pore objects larger than 4.0 mm, and satisfactory results are shown in terms of the strength and resolution of printing high detail cavity structures. This work provides a high value-added upcycling scheme for waste building gypsum that has great potentiality for future industrial application.
研究领域:
建筑材料学
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资源与环境工程
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材料科学与工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Changhao Wu,Xudong Yu,Nan Zhang,Jing Li,Qi Li,Yousheng Yang,Ke Chen,Bo Yang,Shuang Wang,Yiping Liu,Zhenwen Xing
To solve the massive accumulation of gypsum generated from polyhalite leaching and secondary gypsum, this study investigated phase equilibria of the ternary system NH 4 + , Ca 2+ // SO 4 2- - H 2 O at 323.2 K and 348.2 K. The phase diagrams included 2 invariant points, 3 univariate curves, and 3 crystallization regions corresponding to (NH 4 ) 2 SO 4 , CaSO 4 ·2H 2 O, and double salt koktaite (NH 4 ) 2 Ca(SO 4 ) 2 ·H 2 O. As temperature increased, the crystallization region of CaSO 4 ·2H 2 O contracted, whereas those of (NH 4 ) 2 SO 4 and koktaite expanded, indicating that the temperature-enhanced was beneficial to improve the crystallization efficiency of koktaite. Guided by multitemperature phase diagram, the influencing factors and optimal conditions of the comprehensive utilization process of phosphogypsum were explored. The synthesis of koktaite achieved maximum efficiency under conditions of 1: 1.5 molar ratio, 348.2 K reaction temperature, 90 min duration, and 250 rpm agitation. Concurrently, under solid-liquid ratio of 1: 0.5 and after three leaching cycles of 30 seconds each, the yield of CaSO 4 ·2H 2 O production reached 99.80% with a purity of 99.52%. However, the purity and yield of product decreased due to the accumulation of impurities during the cycles, stabilizing after 6 cycles (koktaite yield: 98.50%; purity: 95.69%; (NH 4 ) 2 SO 4 yield: 97.69%; purity: 95.42%). Granulated koktaite released NH 4 + through layer-by-layer dissolution, which prolonged the dissolution time, and the complete dissolution time was 6 times and 24 times longer than that of ungranulated koktaite and (NH 4 ) 2 SO 4 . This work integrates theoretical phase behavior analysis with process engineering to establish a circular resource recovery strategy for synthesizing high-value products from phosphogypsum.
研究领域:
物理化学
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化学工程
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材料科学
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环境科学
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无机化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2024
·
IF 3.7
Yuqian Zhou,Yuhe Zhou,Renlong Liu,Guocan Zheng,Changyuan Tao,Benjun Xi
The resource utilization of phosphogypsum (PG) is the key to promote the green development of the phosphorus chemical industry. The natural environment and public safety are significantly threatened by the enormous volume of PG storage. In this study, Ca and S were successfully recovered from the PG via a multistep precipitation in the NaOH–BaCO3 system. The alkali solution can be recycled five times, with a first recovery ratio of about 97.9%, and the decomposition ratio of PG remained above 70% after five cycles. In addition, the recovery ratios of Ca and S in PG are 99.9 and 82.5%, respectively. The product of BaSO4 can be used as a weighting agent for oil and natural gas drilling mud. The BaSO4 can also be used as wave-absorbing materials, and its reflection loss value reaches 97.8% of the analytical purity BaSO4. This work provides a new idea for the efficient recycling of Ca and S in PG with an outstanding application prospect.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2025
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IF 3.7
Huagui Jin,Xuebin An,Shizhao Wang,Yunshan Wang,Gang Yang,Yong Sun
s This study investigates the removal of fluorine (F) impurities from phosphogypsum (PG) using steam as the reaction medium. The effects of the reaction atmosphere, temperature, time, and steam velocity on F impurities removal were systematically examined. The results showed that with a steam velocity of 0.0184 m·s −1 , a reaction temperature of 700 °C, and a reaction time of 60 min, the F removal rate reached 95.87%. Further investigations into the defluorination mechanism revealed that steam and SiO 2 synergistically enhance fluoride removal, playing a crucial role in improving the defluorination efficiency. Kinetic analysis of the defluorination process, based on the shrinking core model (SCM), indicated that internal diffusion is the rate-controlling step, with the activation energy of 30.12 kJ·mol −1 . This study identifies optimal conditions for PG defluorination and proposes a defluorination mechanism, contributing to the theoretical understanding of impurity removal through the thermal treatment of PG.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
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IF 9.136
Yu Yong,Hu Jianhang,Li Yongkui,Zhong Dapeng,Wang Hua
Arsenic ( As ) -bearing gypsum sludge, one of the biggest As-bearing wastes, has seriously threatened ecological security due to the great mobility and leaching toxicity of As. Unfortunately, most of this sludge was discharged into tailing ponds without treatment. In this paper, a novel co-process of As-bearing gypsum sludge, waste carbon cathode (WCC) and Fe powder for simultaneous separation and solidification of As is proposed via reduction-magnetic separation. In the reduction process, Ca 3 (AsO 4 ) 2 was reduced and then enriched to α-Fe (Fe-As solid solution), and the As solidification ratio reached 90.5%. Meanwhile, NaF in waste carbon cathodes was transformed into CaF 2 and NaCa 2 FSiO 4 . The As and F leached content were only 0.053 mg/L and 3.10 mg/L, when evaluated using the toxicity characteristic leaching procedure. After magnetic separation, α-Fe (magnetic phase) was separated and recovered, and the weight and volume losses of As-bearing waste were 70% and 60%, respectively, compared with the raw material. The As residual content in the non-magnetic phase met the standard of solid waste (As < 0.1 wt%), which acted as a flux during the smelting process, minimizing the environmental risk and realizing resource recycling. Moreover, waste carbon cathodes can be reused as fuel and as a reducing agent, which significantly reduces production costs. This proposed technique reduces hazardous waste, is more effective, and is also more economical.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2025
·
IF 7.8
Wencheng Hou,Wentao Guo,Xiangjun Liu,Zhuoyang Li,Hongxia Li
Desulfurized gypsum, a byproduct of industrial processes, can be efficiently recycled through solid-phase reaction to synthesize CaFe 2 O 4 . This study investigates the reaction mechanism of CaFe 2 O 4 formation from CaSO 4 , Fe 2 O 3 , and semi-coke powder using thermodynamic modeling with Factsage 8.3 software. The phase composition and microstructure of the resulting products under varying semi-coke contents and sintering temperatures were characterized using X-ray diffraction (XRD) and scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS). Total Fe and S contents were quantified using inductively coupled plasma optical emission spectroscopy (ICP-OES) and a C/S Analyzer. The results indicate that increasing the semi-coke content from 11.11 wt% to 20.00 wt% leads to an initial rise and subsequent decline in CaFe 2 O 4 yield, while S content exhibits an opposite trend. Similarly, elevating the sintering temperature from 1050°C to 1150°C results in increased CaFe 2 O 4 formation up to 1125°C, beyond which a decrease is observed, alongside a continuous reduction in S content. Optimal synthesis conditions were identified at 15.79 wt% semi-coke and 1125°C, achieving a desulfurization rate of 95.40 % and confirming effective formation of CaFe 2 O 4 . Compared to conventional reducing agents such as coke and C powders, the use of semi-coke enabled a reduction in the required sintering temperature from 1150°C to 1125°C. These results provide a valuable reference for the low-temperature, high-efficiency recycling of desulfurized gypsum into functional ferrite materials.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
DESALINATION
·
2022
·
IF 11.211
Songchen Xie,Ngie Hing Wong,Jaka Sunarso,Qiang Guo,Chunguang Hou,Zhiguang Pang,Yuelian Peng
Mineral scaling is one of the major challenges for membrane distillation in concentrating high-salinity brine. This work first investigated the characteristic of CaSO 4 scaling, then explored different cleaning reagents to evaluate their efficiencies and mechanisms. By analyzing the SEM and EDX mapping images, the CaSO 4 scaling process could be divided into surface and pore scaling stages. Three cleaning solutions, i.e., commercial detergent (20 %), EDTA-4Na (0.05 M), and MgCl 2 (0.8 M), were chosen for their high CaSO 4 solubility (0.7 g CaSO 4 per 100 g H 2 O). At the surface scaling stage, three cleaning solutions exhibited excellent removal of CaSO 4 scaling with approximately similar 96 % cleaning efficiencies. However, at the pore scaling stage, only the commercial detergent showed high efficiency (89 %). Such high cleaning efficiency was mainly attributed to the detergent's high total dissolved solids (salinity), low pH, and high diffusion rate (5.46 μm cm −1 min −1 ) across the membrane. Moreover, periodic cleaning at the surface scaling stage with the commercial detergent followed by drying throughout a 43.5 h continuous concentration test on an actual RO brine could restore the PTFE membrane performance completely, giving 90 % of the total water recovery . This work provides new insights into the cleaning mechanism for gypsum scaling in a hydrophobic porous membrane.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 15
·5211
·
IF 3.4
Xi Li,Maoyu Ran
This paper introduces a new type of gypsum-based humidity-control material. The material combines gypsum–silica gel humidity-control material with 20% sepiolite powder activated by calcium chloride. Both experimental and simulation studies were conducted to assess its humidity-control performance. The experimental results indicate that gypsum-based humidity-control material has the property of absorbing moisture in high-humidity environments and releasing moisture in low-humidity environments. Moreover, both environmental temperature and relative humidity (RH) have an impact on the material’s humidity-control performance. At a relative humidity of 97.4%, the maximum equilibrium moisture content of the material is 0.225 g/g, which is 1.4 times that of the gypsum–silica gel humidity-control material and 4.5 times that of pure gypsum material. The simulation results indicate that gypsum-based humidity-control material effectively mitigates indoor relative humidity fluctuations and maintains indoor air relative humidity within a narrow range. Furthermore, the material has the potential to reduce building energy consumption. This is especially evident under climate conditions with large temperature and relative humidity differences between day and night, such as in Beijing, Paris, and Atlanta. The maximum potential energy-saving rate in Beijing can reach up to 19.31%.Keywords:humidity control;composite material;energy saving simulation;gypsum
研究领域:
建筑材料
·
能源工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2022
·Vol. 106
·期 7
·2677-2688
·
IF 5.56
Li Jintao,Duan Yingce,Hu Ziyi,Yang Fan,Wu Xiangli,Zhang Ruiying
Abstract Lentinula edodes is one of the most important commercially cultivated edible mushrooms. It is well known that gypsum (CaSO 4 ·2H 2 O) supplementation in sawdust medium increases the yield of L. edodes , while the physiological mechanisms remain unclear. Our previous study showed that the acidification of the medium to pH 3.5–4.0 was essential for the growth of L. edodes . In this study, it was found that the oxalic acid excreted by L. edodes was responsible for the acidification of the medium. The biosynthesis of oxalic acid was regulated by the ambient pH and buffer capacity of the medium. To acidify the sawdust medium, the concentrations of total and soluble oxalate were 51.1 mmol/kg and 10.8 mmol/kg, respectively. However, when the concentration of soluble oxalate was 8.0 mmol/kg, the mycelial growth rate decreased by 29% compared with the control. Soluble oxalate was toxic to L. edodes , while soluble sulfate was nontoxic. CaSO 4 reacted with soluble oxalate to form nontoxic insoluble CaC 2 O 4 and the strong acid H 2 SO 4 . When the CaSO 4 supplemented in sawdust medium was more than 25 mmol/kg, the soluble oxalate decreased to less than 1 mmol/kg, and the mycelial growth rate increased by 32% compared with the control. In conclusion, gypsum improved the growth and yield by relieving the toxicity of oxalate and facilitating the acidification of sawdust medium. Key points L. edodes excretes oxalic acid to acidify the ambient environment for growth. Soluble oxalate is toxic to L. edodes. Gypsum increases growth by reacting with oxalate to relieve its toxicity. Graphical abstract
研究领域:
真菌学
·
植物生理学
✓ 已验证
DOI
PubMed
高影响因子
Materials
·
2019
·Vol. 12
·期 7
·1132
·
IF 2.972
Kuangyi Hu,Zhenping Sun
Influence of polycarboxylate superplasticizers (PCs) with different functional units on the hydration heat and hydration products of C3A-gypsum was investigated. Three kinds of PCs with different monomers were discussed. It was seen that PCs mainly shortened the induction stage of C3A-gypsum hydration, and the amount of remaining gypsum was related to the duration of the induction stage. The second heat flow peak of the sample with PCs was higher than that of the blank. Moreover, PC intercalation occurred during the hydration.Keywords:polycarboxylate superplasticizers;C3A-gypsum;functional units;hydration
研究领域:
建筑材料学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）