scholarly journals Evaluating radiation risks and resource opportunities associated with phosphogypsum in the Philippines

2021 ◽  
Author(s):  
Reymar R. Diwa ◽  
Estrellita U. Tabora ◽  
Botvinnik L. Palattao ◽  
Nils H. Haneklaus ◽  
Edmundo P. Vargas ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Rare Earths ◽  
Acid Production ◽  
The Philippines ◽  
Raw Material ◽  
Surface Samples ◽  
Radiometric Survey ◽  
Activity Concentrations ◽  
Secondary Raw Material

AbstractPhosphogypsum (PG) accumulates during wet-phosphoric acid production for fertilizers. In the Philippines, PG is partly (40%) utilized to produce gypsum walls and cement. This work assesses the radiological risks and resource opportunities associated with PG stacks in the Philippines. The conducted in situ radiometric survey measured the activity concentrations of 40K, 238U, and 232Th at 270 locations. Besides, another 120 surface samples were collected. Pure PG exceeds the recommended radiation limits, but simple dilution with conventional materials can make PG available as an inexpensive secondary raw material for construction. PG further contains relevant concentrations of rare earths and Y (195 ppm).

scholarly journals In situ Ground Radiometric Survey and Risk Assessments of Allanite-Bearing Beach Sands in Erawan, Palawan

2021 ◽  
Author(s):  
Reymar Diwa ◽  
Edmundo Vargas ◽  
Estellita Tabora ◽  
Botvinnik Palattao ◽  
Rolando Reyes ◽  
...  
Keyword(s):  
Local Population ◽  
Hazard Index ◽  
The Philippines ◽  
Risk Assessments ◽  
Anthropogenic Sources ◽  
World Average ◽  
Radiometric Survey ◽  
The World ◽  
The Mean

Past exploration for U deposit in the Philippines discovered the mineralization of radioactive allanite in Palawan. The allanite occurs as sand component in the heavily populated beach of Erawan, San Vicente, Palawan. This work assessed the risks associated with the radionuclides in Erawan beach by in situ ground radiometric survey of K, U, and Th in 694 sampling points. Principal component analysis (PCA) and Pearson correlation coefficient were used to determine the similarity between the radionuclides and to identify other probable anthropogenic sources of radionuclides. Our results show that the mean activity concentrations of K (597.8 Bq kg-1) and Th (93.15 Bq kg-1) are equivalent to 1.5 and 3.1 times of the world average natural radioactivity levels in soil, respectively, while the mean U (34.7 Bq kg-1) is similar to the world average. The mean radiological risk assessments like radium equivalent, gamma specific activity index, external hazard index, internal hazard index, absorbed gamma dose rate, annual effective dose equivalent, annual gonadal equivalent dose, and excess lifetime cancer risk are 213.96 Bq kg-1, 0.78, 0.58, 0.67, 97.24 nGy h-1, 119.25 µSv y-1, 684.39 µSv y-1, and 0.42 (10-3), respectively. Th consistently correlated most to the risks. We attribute the occurrence of Th to the presence of allanite, K to fertilizer use for farming, and U to both the allanite and farming. The results of our study can provide important baseline data for future detailed studies or monitoring of the long-term effects of elevated radiation levels to the local population of Erawan.

scholarly journals HIGH-TEMPERATURE DECONTAMINATION AND UTILIZATION OF PHOSPHOGYPSUM

2004 ◽  
Vol 12 (4) ◽  
pp. 138-145
Author(s):  
Algimantas Kazragis
Keyword(s):  
High Temperature ◽  
Phosphoric Acid ◽  
Central Region ◽  
Acid Production ◽  
Environmental Problems ◽  
Raw Material ◽  
Toxic Pollutants ◽  
The City ◽  
Hemi Hydrate ◽  
Full Operation

Waste piles of phosphogypsum formed from deposits of phosphoric acid production by‐product loom near the city of Kedainiai in the center of Lithuania. Every year about 250 thousand tons of this by‐product were gathered when the plant was in full operation. At present, about 13 to 15 million tons of phosphogypsum have accumulated which is mainly gypsum dihydrate – (95–98) %, however, contaminated with phosphoric and fluoric acids as well as with other hazardous admixtures what makes this raw material ecologically harmful and also hampers the use of phosphogypsum instead of natural gypsum for the production of binding materials. These materials pollute the environment. Phosphogypsum can be “deacidified” with lime and then treated as normal natural gypsum to obtain hemi hydrate gypsum. However, good‐quality binding materials were not obtained in this case. Heating of phosphogypsum up to a temperature of 600 °C provides for the decomposition and elimination of binding obstruction admixtures. Heating to 1000 °C and higher temperatures causes the decomposition of the former with the formation of an activator in anhydrite lime and thus anhydrite cement. In general, the utilization of this environmentally harmful waste and the binding of toxic pollutants can contribute to the solution of environmental problems in the central region of Lithuania.

Laboratory Burning of Anhydrite from Phosphogypsum

2015 ◽  
Vol 1100 ◽  
pp. 60-63
Author(s):  
Dominik Gazdič ◽  
Karel Dvořák ◽  
Iveta Hájková
Keyword(s):  
Phosphoric Acid ◽  
Mineralogical Composition ◽  
Raw Material ◽  
Hydration Process ◽  
Technological Properties ◽  
Material Resources ◽  
Secondary Raw Material ◽  
Burning Mode ◽  
Selection Of

The objective of this work is a research in the sector of preparation of anhydrite II based sulphate binder made from secondary raw material resources applicable in industry specialised in production of mortar mixtures. In particular it was a laboratory burnout of anhydrite II from phosphogypsum, which is formed during production of phosphoric acid. The selection of burning mode was done upon the results [1]. The selected burning mode influence on mineralogical composition of formed anhydrite was monitored with subsequent setting of basic technological properties and monitoring of hydration process course.

scholarly journals Quarry Waste: Chances of a Possible Economic and Environmental Valorisation of the Montorfano and Baveno Granite Disposal Sites

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
G. A. Dino ◽  
M. Fornaro ◽  
A. Trentin
Keyword(s):  
Chemical Analysis ◽  
Field Work ◽  
Raw Material ◽  
Lake District ◽  
Dry Process ◽  
Ore Bodies ◽  
Geophysical Surveys ◽  
Secondary Raw Material ◽  
Granite Samples

The Montorfano and Baveno granite ore bodies are located in the Lake District (VCO-NE Piedmont). They were and are still quarried as dimension stones, with a consequent production of a huge volume of “waste.” In 1995, an Italian company (GMM S.p.A) decided to invest in the valorisation of granite quarry waste as a secondary raw material. An in situ geological prospecting was carried out in order to evaluate the characteristics of the material and the thickness and volume of the useful disposal sites that could be used (by means of geophysical surveys). As a consequence of the field work, the amount of quarry waste was estimated as nearly 2 Mm3. Chemical analysis was carried out on 75 granite samples, in order to individuate the Fe2O3 grade: from 1.321–2.593% of the original waste to 0.160–0.228% after the “dry process” treatment. Three different detailed maps that show the typology, the locations, and the quality distribution of the material in the dumping areas have been drawn up.

Overview of Current Phosphoric Acid Production Processes and a New Idea of Kiln Method

2020 ◽  
Vol 17 ◽  
Author(s):  
Guangya Zheng ◽  
Jupei Xia ◽  
Zhengjie Chen
Keyword(s):  
Phosphoric Acid ◽  
Acid Production ◽  
Phosphate Rock ◽  
Low Grade ◽  
Production Methods ◽  
Production Processes ◽  
Major Equipment ◽  
Development Prospects ◽  
Great Competitiveness

: China primarily contains medium and low-grade phosphorus ores that are used to produce phosphoric acid. Here, we provide an overview of phosphoric acid production processes, including wet, thermal, and kiln methods, as well as the fundamental principles, major equipment, and technological aspects of each process. Progress in the kiln method using lowgrade phosphate rock is described, which involves the KPA and CDK processes. The literature shows that the addition of admixtures adds great competitiveness to kiln phosphate production methods and has considerable development prospects.

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