Alkaline refining of crude lead: a method of arsenic removal and the behavior of arsenic in the process

2022 ◽  
Vol 119 (1) ◽  
pp. 105
Author(s):  
Rong Zhu ◽  
Hailin Long ◽  
Haoyu Li ◽  
Huimin Xie ◽  
Shaohua Yin ◽  
...  

In this work, the alkaline refining of arsenic in crude lead was studied with a mixture of sodium hydroxide and sodium carbonate as alkaline refining agents. Taking the arsenic removal rate as the research object, the effects of reaction temperature, holding time, Na2CO3:NaOH, the dosage of refining agent were investigated. The arsenic removal rate is 79.09% under the optimum experimental conditions as follows: reaction temperature 823 K, holding time 60 min, Na2CO3:NaOH 1:4, refining agent dosage 10%. The oxidation purification mechanism of arsenic was studied by XPS, SEM-EDS, XRD and FT-IR. The results show that arsenic in the crude lead is gradually oxidized by oxygen and lead oxide during arsenic removal process, and the arsenic trioxide is eventually converted into sodium arsenate (Na3AsO4) and lead arsenate (Pb2As2O7) in the slag.

2011 ◽  
Vol 284-286 ◽  
pp. 238-241 ◽  
Author(s):  
Qing Lu ◽  
Shu Hui Zhang ◽  
Xiao Hu

The physicochemical properties of iron ore with arsenic in South of China was analyzed by chemical analysis, XRD, high power microscope. The effects of various factors on arsenic removal in sintering process were studied and the optimal technique parameters were obtained. The results show that the mineral of iron ore with arsenic in South of China mainly is composed of magnetite and gangue, in which arsenic with 0.282% mass content exists as FeAsS and few as As2S3. The oxidation and thermal decomposition reaction of FeAsS occurs in sintering process. Under feeble oxidation atmosphere the arsenic removal rate of iron ore along with reaction temperature increases, and the holding time elongates, or the coke powder content rises. The optimal removal arsenic process parameter is: reaction temperature 1050~1100°C, holding time 8~15min, and coke powder content 6%.


2013 ◽  
Vol 690-693 ◽  
pp. 1013-1019
Author(s):  
Xiao Juan Chen ◽  
Liu Chun Yang ◽  
Jun Feng Zhang ◽  
Yan Huang

Calcium sulfate whisker (CSW) was prepared through the method of cooling recrystallization. In an attempt to develop its new application in environmental protection, we investigated the effect of calcination on the material properties and arsenic uptake performance of calcium sulfate whisker anhydrate (CSAW), which was obtained from CSW calcined at 600 °C for 2 h. Moreover, XRD, SEM, optical microscope, and FT-IR were used to characterize CSW samples. It was found that calcination played an important role in the whisker structure through changing the content of crystal water and the morphology. The CSAW material exhibited a high removal rate of As3+/As5+under strongly alkaline condition.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2741
Author(s):  
Pengcheng Lv ◽  
Ruihong Meng ◽  
Zhongyang Mao ◽  
Min Deng

In this study, the hydrated sodium aluminosilicate material was synthesized by one-step hydrothermal alkaline desilication using fly ash (FA) as raw material. The synthesized materials were characterized by XRD, XRF, FT-IR and SEM. The characterization results showed that the alkali-soluble desilication successfully had synthesized the sodium aluminosilicate crystalline (N-A-S-H) phase of sodalite-type (SOD), and the modified material had good ionic affinity and adsorption capacity. In order to figure out the suitability of SOD as an adsorbent for the removal of ammonium and phosphorus from wastewater, the effects of material dosing, contact time, ambient pH and initial solute concentration on the simultaneous removal of ammonium and phosphorus are investigated by intermittent adsorption tests. Under the optimal adsorption conditions, the removal rate of ammonium was 73.3%, the removal rate of phosphate was 85.8% and the unit adsorption capacity reached 9.15 mg/L and 2.14 mg/L, respectively. Adsorption kinetic studies showed that the adsorption of ammonium and phosphorus by SOD was consistent with a quasi-secondary kinetic model. The adsorption isotherm analysis showed that the equilibrium data were in good agreement with the Langmuir and Freundlich model. According to thermodynamic calculations, the adsorption of ammonium and phosphorus was found to be a heat-absorbing and spontaneous process. Therefore, the preparation of SOD by modified FA has good adsorption properties as adsorbent and has excellent potential for application in the removal of contaminants from wastewater.


2020 ◽  
Vol 82 (8) ◽  
pp. 1635-1642
Author(s):  
Ling Zhou ◽  
Zhongying Xu ◽  
Jie Zhang ◽  
Zhifang Zhang ◽  
Ying Tang

Abstract To seek for efficient Fenton-like oxidation processing for treatment of waste fracturing fluid containing hydroxypropyl guar gum (HPGG), in heterogeneous reaction, five bentonite-supported zero-valent metal catalysts were prepared by liquid-phase reduction. The results showed that the bentonite-supported zero-valent copper exhibited best catalytic performance, attributed to the high dispersion of active sites of zero-valent copper. The effects of the most relevant operating factors (H2O2 concentration, catalyst dosage, temperature and pH) were evaluated in detail. Moreover, the chemical oxygen demand removal rate of HPGG can achieve 76% when the reaction time was selected at 45 min under optimal experimental conditions. The stability evaluation showed that the catalytic performance was almost unaffected after the catalyst was recycled and used once more showing the good stability of the bentonite-supported zero-valent copper in the application process.


2015 ◽  
Vol 713-715 ◽  
pp. 2909-2912
Author(s):  
Bin Zhao ◽  
Li Ke Zou ◽  
Guo Yong Li

Cuprous oxide catalyst was prepared and applied as photocatalist to treat chromium (VI) in wastewater, and the photocatalytic activity of the cuprous oxide was studied. The optimal conditions for the treatment was as follows: the pH of wastewater was 3, the amount of catalysts was 0.3 g/L, the reaction temperature was 60°C. Under the optimal conditions, the removal rate of chromium (IV) in wastewater reached 50% in the presence of cuprous oxide catalyst.


2010 ◽  
Vol 61 (5) ◽  
pp. 1235-1243 ◽  
Author(s):  
Y. F. He ◽  
F. R. Li ◽  
R. M. Wang ◽  
F. Y. Li ◽  
Y. Wang ◽  
...  

Xanthate was successfully grafted onto bentonite by a relatively simple solution reaction. The obtained xanthated bentonite (XBent) was characterized by FT-IR spectrophotometer, thermogravimetric analysis (TG), particle size analysis, x-ray diffraction (XRD) and scanning electron microscopy (SEM). XBent acting as a type of environmentally friendly adsorbent was applied to remove lead ions from aqueous solutions. The optimum conditions were as follows: [Pb2 + ] = 500 mg L−1, [XBent] = 2 g L−1, pH = 5.0; oscillating 60 min under 200 rpm at 25°C. The removal rate of lead was up to 99.9%. It was found that the lead(II) ions—XBent adsorption isotherm model fitted well to the Freundlich isotherm. The adsorption mechanism was also investigated by SEM and XRD, which concluded that lead ions were complexed or chelated with XBent. XBent appears to have potential to be used later in water treatment as a type of inorganic polymer reagent.


1995 ◽  
Vol 12 (3) ◽  
pp. 221-229 ◽  
Author(s):  
S.A. El-Hakam

The effect of heat treatment of manganese oxide/alumina catalysts of various manganese content on the structural and textural properties and the catalytic decomposition of hydrogen peroxide were investigated. The FT-IR results have shown that depending on the calcination temperature and metal loading MnO2 and MnO3 are formed on the investigated samples. No spinel structure was detected under the experimental conditions. The surface areas were found to decrease with increasing calcination temperature and metal content up to 30 wt.% Mn. The mean pore radius increased with both calcination temperature and Mn content. The rate of catalytic decomposition of H2O2 was found to depend on the pH, the calcination temperature and the state of Mn on the catalyst surface.


2011 ◽  
Vol 189-193 ◽  
pp. 404-409
Author(s):  
Fu Quan Peng ◽  
Zhen Cheng Xu ◽  
Jian Hong Huang ◽  
Qing Wei Guo ◽  
Feng Nie

Different adsorptive mediums and adsorbents’ compounds were chosen to remove arsenic from Yangzonghai Lake wastewater. Results showed that Ca(OH)2, attapulgite, bentonite, LDHs these adsorptive mediums had adsorptive capacities of less than 2.5 mg/g of As removal and it took long time for sediment before monitoring; adsorbents compounds’ results showed Fe2O3 and quartz sands had best removal rate and quartz sands had little removal of arsenic. Both strong anion resin and hydrated ferrous oxide-loaded on polystyrene diethanolamine resin(designated as PDR-HFO) can decrease As concentration to less than 0.01 mg/L reaching national standards for arsenic; anions such as SO42- can not be removed when strong anion resin was regenerated causing its loss of exchange ions; PDR-HFO exhibited excellent adsorptive properties and recyclability.


2013 ◽  
Vol 634-638 ◽  
pp. 526-530
Author(s):  
Chun Xiang Geng ◽  
Qian Qian Chai ◽  
Wei Yao ◽  
Chen Long Wang

Selective Catalytic Reduction (SCR) processes have been one of the most widely used denitration methods at present and the property of low tempreture catalyst becomes a hot research. The Mn-Ce/TiO2 catalyst was prepared by incipient impregnation method. The influence of load capacity, reaction temperature, O2 content, etc. on denitration were studied by a fixed bed catalyst reactor with ammonia gas. Results showed that catalyst with load capacity 18% performed high NO removal rate of 90% at conditions of reaction temperature 160°C, low space velocity, NH3/NO molar ratio 1: 1, O2 concentration 6%.


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