A novel and efficient strategy mediated with calcium carbonate-rich sources to remove ammonium sulfate from rare earth wastewater by heterotrophic Chlorella species

2021 ◽  
pp. 125994
Author(s):  
Youcai Zhou ◽  
Yongjin He ◽  
Xuehua Xiao ◽  
Zhibo Liang ◽  
Jingxuan Dai ◽  
...  
Keyword(s):  
Rare Earth ◽  
Calcium Carbonate ◽  
Ammonium Sulfate ◽  
Efficient Strategy ◽  
Chlorella Species

scholarly journals Dissolution kinetics of rare earth metal phosphates in carbonate solutions of alkali metals

2021 ◽  
Vol 251 ◽  
pp. 712-722
Author(s):  
Tatyana Litvinova ◽  
Ivan Oleynik
Keyword(s):  
Rare Earth ◽  
Calcium Carbonate ◽  
Alkali Metal ◽  
Ammonium Sulfate ◽  
Rare Earth Metal ◽  
Ammonium Carbonate ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Phosphate Dissolution ◽  
Carbonate Complexes

Treatment of apatite raw materials is associated with the formation of large-tonnage waste – phosphogypsum. The content of rare earth metals in such waste reaches 1 %, which makes it possible to consider it a technogenic source for obtaining rare earth metals and their compounds. Up to the present moment, there are neither processing plants, nor an efficient process flow to handle phosphogypsum dumps. It is rational to use a way that involves extraction of valuable components and overall reduction of phosphogypsum dumps. Such process flow is available with carbonate conversion of phosphogypsum to alkali metal or ammonium sulfate and calcium carbonate upon the condition of associated extraction of rare earth metal (REM) compounds. Associated extraction of REM compounds becomes possible since they form strong and stable complexes with hard bases according to Pearson, which among other things include carbonate, phosphate and sulfate anions. Formation of lanthanide complexes with inorganic oxygen-containing anions is facilitated by the formation of high-energy Ln-O bonds. The study focuses on the dissolution of lanthanide phosphates in carbonate media. It was established that formation of REM carbonate complexes from their phosphates is a spontaneous endothermic process and that formation of lanthanide carbonates and hydroxides serves as thermodynamic limitation of dissolution. A shift in equilibrium towards the formation of carbonate complexes is achieved by increasing the temperature to 90-100 °C and providing an excess of carbonate. The limiting stage of REM phosphate dissolution in carbonate media is external diffusion. This is indicated by increasing rate of the process with an intensification of stirring, first order of the reaction and the value of activation energy for phosphate dissolution from 27 to 60 kJ/mol. A combination of physical and chemical parameters of the process allowed to develop an engineering solution for associated REM extraction during carbonate conversion of phosphogypsum, which included a 4-5 h conversion of phosphogypsum at temperature of 90-110 °C by an alkali metal or ammonium carbonate solution with a concentration of 2-3 mol/l. As a result, a solution with alkali metal (ammonium) sulfate is obtained, which contains REMs in the form of carbonate complexes and calcium carbonate. The rate of REM extraction into the solution reaches no less than 93 %. Rare earth metals are separated from the mother liquor by precipitation or sorption on anion exchange resins, while the excess of alkali metal or ammonium carbonate is returned to the start of the process.

Recovery of rare earth elements adsorbed on clay minerals: II. Leaching with ammonium sulfate

2013 ◽  
Vol 131-132 ◽  
pp. 158-166 ◽  
Author(s):  
Georgiana A. Moldoveanu ◽  
Vladimiros G. Papangelakis
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Ammonium Sulfate ◽  
Clay Minerals

An extraction and precipitation process for the removal of Ca and Mg from ammonium sulfate rare earth wastewaters

2019 ◽  
Vol 187 ◽  
pp. 63-70
Author(s):  
Shuainan Ni ◽  
Caibin Wu ◽  
Yanliang Wang ◽  
Xiangguang Guo ◽  
Zeyuan Zhao ◽  
...  
Keyword(s):  
Rare Earth ◽  
Ammonium Sulfate ◽  
Precipitation Process

scholarly journals SOIL GEOCHEMISTRY ADJACENT TO CARBONATITES FROM CAÇAPAVA DO SUL, RS, BY FLUORESCENCE OF X-RAYS BY DISPERSIVE ENERGY

2020 ◽  
Vol 39 (04) ◽  
pp. 953-963
Author(s):  
Cristiane Heredia GOMES ◽  
Plínio BRIOSCHI NETO ◽  
Guilherme Alves MARQUES ◽  
Guilherme Pazinato DIAS ◽  
Diogo Gabriel SPERANDIO
Keyword(s):  
Rare Earth ◽  
Calcium Carbonate ◽  
Chemical Composition ◽  
Rare Earth Elements ◽  
X Rays ◽  
Soil Geochemistry ◽  
High Chance

Currently, carbonatites are being severally studied in a prospective matter due to their high chance of containing calcium carbonate, magnesium and iron. They are also considered extremely rich in phosphate and minerals rich in Rare Earth Elements (ETR). In this context, the municipality of Caçapava do Sul has two occurrences of carbonatites: Picada de Tocos and Passo Feio. In order to enrich knowledge and assist in carbonate prospecting, this work aimed to characterize the soil geochemistry at the occurrences of the carbonatites in Caçapava do Sul. The data obtained revealed that there is an anomalous presence of Ca, Mg, Fe, Ti, P, Mn, Co, Th and Ce elements. This anomaly is directly linked to the presence of carbonatites in the region and their chemical composition.

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