Selective removal of arsenic(V) from a molybdate plant liquor by precipitation of magnesium arsenate

Abstract

Precipitation of Mg 3 (AsO 4 ) 2 for the removal of arsenic (As) from a molybdenum oxide processing plant liquor containing 70.9 g/L Mo(VI) and 469 mg/L As(V) was performed.. The Stabcal software was used to model the speciation and solubility equilibria, and to identify the pH conditions at which optimum precipitation can be carried out. The optimum pH range for As(V) removal is between pH 7.5 to 10.2. This avoids the need to adjust the liquor pH to affect the precipitation. By adding magnesium chloride or sulphate at a Mg:As molar ratio of at least 2:1, As(V) could be removed to less than 5 mg/L at pH 10.2 resulting in a pure Mo(VI) liquor from which a high purity product of 99.9% MoO 3 could be produced by acidification.

A facile template free solution approach for the synthesis of dypingite nanowires and subsequent decomposition to nanoporous MgO nanowires with excellent arsenate adsorption properties

“…So, Mg(OH) 2 reacted with HAsO 4 22 to form magnesium arsenate. 54,55 As a result, the structures of MgO were destroyed step by step after As(V) adsorption, as shown in Fig. 14 (Fig.…”

Comparative study on arsenate removal mechanism of MgO and MgO/TiO2 composites: FTIR and XPS analysis

“…35 This demonstrates that As(V) ions reacted with Mg(OH) 2 to form some types of magnesium arsenate. 36,37 We believe that the As(V) ion removal resulted from the reaction of Mg(OH) 2 and As(V) ions.…”

Removal of Arsenate from Contaminated Water via Combined Addition of Magnesium-Based and Calcium-Based Adsorbents

“…In addition to the above studies on Fe-based adsorbents and so on, many studies on Mg-based and Ca-based adsorbents have been conducted for the purpose of As removal. Park et al [30] used magnesium chloride or magnesium sulfate to remove As(V) from a molybdenum oxide processing plant liquid containing approximately 70 g/L of Mo(VI) and 470 mg/L of As(V). The addition of MgO as a precipitating agent was also tested.…”