Properties of Cemented Filling Materials Prepared from Phosphogypsum-Steel Slag–Blast-Furnace Slag and Its Environmental Effect
5
Citation
74
Reference
10
Related Paper
Citation Trend
Abstract:
Phosphogypsum (PG) occupies a large amount of land due to its large annual production and low utilization rate, and at the same time causes serious environmental problems due to toxic impurities. PG is used for mine backfill, and industrial solid waste is a curing agent for PG, which can save the filling cost and reduce environmental pollution. In this paper, PG was used as a raw material, combined with steel slag (SS) and ground granulated blast-furnace slag (GGBS) under the action of an alkali-activated agent (NaOH) to prepare all-solid waste phosphogypsum-based backfill material (PBM). The effect of the GGBS to SS ratio on the compressive strength and toxic leaching of PBM was investigated. The chemical composition of the raw materials was obtained by XRF analysis, and the mineral composition and morphology of PBM and its stabilization/curing mechanism against heavy metals were analyzed using XRD and SEM-EDS. The results showed that the best performance of PBM was achieved when the contents of PG, GGBS, and SS were 80%, 13%, and 7%, the liquid-to-solid ratio was 0.4, and the mass concentration of NaOH was 4%, with a strength of 2.8 MPa at 28 days. The leaching concentration of fluorine at 7 days met the standard of groundwater class IV (2 mg/L), and the leaching concentration of phosphorus was detected to be less than 0.001 mg/L, and the leaching concentration of heavy metals met the environmental standard at 14 d. The hydration concentration in PBM met the environmental standard. The hydration products in PBM are mainly ettringite and C-(A)-S-H gel, which can effectively stabilize the heavy metals in PG through chemical precipitation, physical adsorption, and encapsulation.Keywords:
Phosphogypsum
Environmental Pollution
Phosphogypsum
Environmental Pollution
Resource Recovery
Environmentally Friendly
Cite
Citations (154)
The characteristic of phosphogypsum and all kinds of impurities in it together with corresponding pretreatment ways were illustrated.Comprehensive utilization about phosphogypsum was shown in this paper.And some problems in recycling of phosphogypsum were discussed and the corresponding efficient methods were given to solve these problems.
Phosphogypsum
Resource Recovery
Cite
Citations (1)
A new process (patent applied) that works equally well with both plaster of mineral gypsum and phosphogypsum for the preparation of gypsum components, UCOS, has been developed. The process consists of the following steps: humidification of plaster by fine water droplets, uni‐axial compression, hydration reaction and drying. Strong hydrogen bonds develop among the crystals together with adhesion provided by confined water that accounts for nearly 70% of the adhesion forces. By reducing the plaster to water ratio to close the minimum necessary, new features are generated. An experimental house has been constructed, in which walls and ceilings have been built of gypsum and phosphogypsum. Since phosphogypsum potentially contain radioactive elements, the application of an activity concentration index to the phosphogypsum employed in the building was carried out.
Phosphogypsum
Cite
Citations (8)
Uncontrolled emissions of phosphogypsum have caused serious environmental pollution and waste of resources.Current comprehensive utilization rate of phosphogypsum at home is lower.Its main applications are in building materials industry,producting chemical raw materials and agriculture.Comprehensive utilization of phosphogypsum should becarried out in economic and environmental friendly way and develop utilization way of large usage,high technological added value and having demonstration effect.
Phosphogypsum
Environmental Pollution
Environmentally Friendly
Cite
Citations (0)
在用有玉米秆的猪粪肥的一个强迫的通风系统的 composting 的一个实验室规模实验被执行调查 phosphogypsum 和 dicyandiamide 的效果(DCD， C2H4N4 ) 作为气体的排出物和堆肥质量上的添加剂。除控制以外，有有添加剂的不同数量的三个修改处理。结果显示以 10% 混合的率的 phosphogypsum 增加弄干重量减少的 NH3 和 CH4 排出物显著地在 composting 期间。以 0.2% 混合的率的 DCD 的增加和 10% phosphogypsum 的干燥重量进一步由影响氮的硝化作用过程减少了 N2O 排放。中等面对 0.2% DCD 把 phosphogypsum 增加归结为 5% 增加了 NH3 排出物然而并非 N2O 排放。添加剂在最后的堆肥显著地增加了铵内容和电的电导率。有机物降级或堆肥的萌芽索引上的不利效果都没在修改处理被发现。phosphogypsum 和 DCD 能为减少 NH3， CH4 和 N2O 排出物的目的在 composting 被使用，这被推荐。DCD 添加剂的最佳的条件和剂量应该在进一步的学习与不同材料和 composting 系统在 composting 期间被决定。
Phosphogypsum
Cite
Citations (0)
Phosphogypsum is a by-product of the wet process production of phosphoric acid,containing fluorine,phosphorus,organic compound,eutectic phosphorus and other impurities,which deteriorate the efficiency of Phosphogypsum and has serious effect on the utilization of phosphogypsum [1]. Different methods and processes of treating the harmful impurities in phosphogypsum were explored and a rational technological way of treating these harmful things was found out.
Phosphogypsum
Phosphoric acid
Phosphorite
Cite
Citations (1)
With the rapid development of phosphate fertilizer industry,its by-product—phosphogypsum has become the difficult problem of the environment protection on the development of phosphate fertilizer.This article describes the origin of the phosphogypsum and its characteristics,and introduces the present situation and the existent advantages and disadvantages of phosphogypsum from a wider range fields of applying phosphogypsum and the hot fields of developing,utilizing and studying phosphorous.
Phosphogypsum
Phosphate fertilizer
Cite
Citations (0)
In recent years, solid waste of the production of mineral fertilizers, phosphogypsum, has been of great scientific and practical interest in construction. The results of scientific research and practical experience in many countries have convincingly proved the technical feasibility and feasibility of using phosphogypsum. The problems of reducing impurities of phosphorus and fluorine in the manufacture of building materials from phosphogypsum are considered. Comparative experimental studies of the presence of phosphorus impurities for the initial phosphogypsum of the Dnieper Mineral Fertilizer Plant, calcined phosphogypsum and mixtures of phosphogypsum were carried out. Comparative indicators of the presence of radioactive elements in phosphogypsum are given. It is shown that there are methods for reducing heavy metals in phosphogypsum.
Phosphogypsum
Cite
Citations (12)
Inovamat Ltda. R. Alberto Lanzone, 731 – 13566-590 Sao Carlos, SP Abstract. A new process (patent applied) that works equally well with both plaster of mineral gypsum and phosphogypsum for the preparation of gypsum components, UCOS, has been developed. The process consists of the following steps: humidification of plaster by fine water droplets, uni-axial compression, hydration reaction and drying. Strong hydrogen bonds develop among the crystals together with adhesion provided by confined water that accounts for nearly 70% of the adhesion forces. By reducing the plaster to water ratio to close the minimum necessary, new features are generated. An experimental house has been constructed, in which walls and ceilings have been built of gypsum and phosphogypsum. Since phosphogypsum potentially contain radioactive elements, the application of an activity concentration index to the phosphogypsum employed in the building was carried out. Keywords: Phosphogypsum, Building Materials, Activity Concentration Index. PACS: 89.20.-a
Phosphogypsum
Cite
Citations (1)
The comprehensive utilization of wet-process phosphoric acid by-product has the great significance for environmental protection and circulation resource adoption.The soluble impurities such as P2O5,fluorine and organic matter in the phosphogypsum are main affecting factors for phosphogypsum using.Some methods about phosphogypsum pretreatment in China and abroad are introduced.
Phosphogypsum
Phosphoric acid
Cite
Citations (1)