arsenic ore dissolution

Arsenic in contaminated waters: Biogeochemical cycle ...

Apart from acute pollution resulting from mining industries, source of arsenic contamination of waters is mainly geogenic, i.e. the dissolution of the arsenic-bearing minerals. Mechanisms of arsenic mobilization are diverse and it is now widely accepted by researchers that micro-organisms have a major role in these processes.

Arsenic: Mitigation Strategies.

• Arsenic is introduced into the aquatic environment from both natural and manmade sources. Typically, however, arsenic occurrence in water is caused by the weathering and dissolution of arsenic-bearing rocks, minerals, and ores. Although arsenic exists in both organic and inorganic

US3911078A - Method for removing arsenic and antimony from ...

Method for removing essentially all of the chemically bonded arsenic and antimony from copper sulfide ores. The arsenic and antimony are selectively leached out using Na2S in a basic solution. The resulting Na3AsS4 and Na3SbS4 are converted to the sulfides or to ferric arsenate and ferric antimonate for safe disposal. Sodium and sulfur values are recovered for recycling in the process.

Arsenic trisulfide - Wikipedia

Arsenic trisulfide is the inorganic compound with the formula As 2 S 3. It is a dark yellow solid that is insoluble in water. It also occurs as the mineral orpiment (Latin: auripigment), which has been used as a pigment called King's yellow. It is produced in the analysis of arsenic compounds.

Separation practice of copper arsenic sulfide ore ...

Separation practice of copper arsenic sulfide ore. The separation of copper and arsenic is mainly to solve the separation problem of copper minerals and arsenopyrite, which can be summarized as follows: (1) Highly selective collector. It is very important to enlarge the separation of the two minerals by using selective collectors.

Mechanochemical Treatment to Remove Arsenic from Copper Ore

This study tested the removal of arsenic from copper ore concentrate via a mechanochemical treatment by planetary ball milling. The harmful components of ore, such as arsenic, are increasing year by year and decreasing the copper grade, therefore there is a strong need to improve the separation of arsenic from copper ore. The effect of grinding as a result of chemical activation caused by ...

LEACHING OF METALS INTO GROUNDWATER …

tests showed reducing conditions (favorable for arsenic dissolution) at 4 of the 16 groundwater wells. Samples were analyzed for arsenic, manganese, lead, iron, and cadmium. Dissolved arsenic was above drinking water standards at one well, but below groundwater standards in all wells. Most of the arsenic was in the particulate form.

Arsenic release and transport during oxidative dissolution ...

The oxidative dissolution of arsenopyrite (FeAsS) and löllingite (FeAs 2) leads to oxygen consumption and to the release of ferrous iron, arsenite and sulfate and are expressed, respectively, as: (1) FeAsS + 2.75 O 2 + 1.5 H 2 O → F e 2 + + H 3 As O 3 + S O 4 2 − and (2) FeA s 2 + 2 O 2 + 2 H 2 O → F e 2 + + 2 H 2 As O 3 −

Water leaching of arsenic trioxide from metallurgical dust ...

Water leaching of As2O3 from metallurgical dust containing various metals was investigated, serving the purpose of dearsenization and simultaneous metal enrichment especially for indium. Effects of leaching temperature, liquid/solid ratio (LSR) and leaching time were studied. It was found that the initial dissolution was very fast but was then so inhibited by the increasingly dissolved …

ii Arsenic rich Iron Oxi hydroxides Reduction Process ...

Arsenic can be released from these arsenic rich iron oxi-hydroxides as a result of dissolution and desorption. A reducing redox environment (oxygen-deficient conditions) in the subsurface can promote dissolution of iron oxi-hydroxides and release of associated arsenic into under ground water.

Dissolution of Arsenic Minerals Mediated by Dissimilatory ...

Arsenic minerals dissolution can be mediated also at circumneutral pH, but mainly by sulfur- and arsenite-oxidizing microbes. It has been documented that the release of pyrite-bound arsenic may be caused by (i) oxidation of sulfide in the pyrite lattice [9] or (ii) direct oxidation of arsenic from mineral structure (e.g., arsenopyrite) [10].

Arsenic cycling in the Earth's crust and hydrosphere ...

Typically, during chemical weathering of arsenic ore deposits and subsequent soil formation, arsenic host phases change as follows: arsenopyrite and löllinite in the ore body become scorodite, pharmacosiderite, and arsenosiderite in the weathered rock, and then arsenic-bearing goethite in soil (Majzlan et al. 2014).

The Role of Arsenic in the Mining Industry

arsenopyrite, the most abundant ore mineral of arsenic. However, arsenic is not recovered from these sources ... Freshwaters and associated ecosystems may be impacted by arsenic dissolution in runoff from contaminated sites. [1] In contrast, it is the natural release of arsenic from geologic

Oxidation of arsenic and gold leaching during cyanidation ...

The dissolution and oxidation of arsenic gradually increase. When the arsenic is reached to a certain extent, these products are easily on the surface of gold minerals. a thin film layer, and gold can seriously hinder CN -chemical reaction between the 2 and O. When the anti-filming agent is added during the cyanidation process, the arsenic ...

Dissolution of arsenic samples | Radiochemistry of Arsenic ...

IX DISSOLUTION OF ARSENIC SAMPLES Since arsenic is most easily separated from other elements, except germanium, as the chloride, it would seem that hydrochloric acid would be the logical solvent for an irradiated sample. However, arsenic is unaffected by hydrochloric acid in the absence of oxygen.

Research Article Dissolution of Arsenic Minerals Mediated ...

minerals through reductive dissolution. We demonstrated thattheisolatedstrains(i)producemetabolitesthatpromote dissolution of minerals, (ii) are resistant to dissolved arsenic compounds, (iii) are able to use the dissolved arsenates as terminalelectronacceptor,and(iv)areabletoremovearsenic under anaerobic conditions from As-containing copper ore

THE OXIDATION AND DISSOLUTION OF ARSENIC-BEARING …

We provide a comprehensive review of research conducted on the dissolution–oxidation of As-bearing sulfides including arsenopyrite, orpiment, realgar, tennantite, and the amorphous forms of As 2 S 3 and AsS. In general, a rise in pH and the presence of Fe 3+ or bacteria (or both) cause the oxidation rates of As-bearing sulfides to increase, except for arsenopyrite.

Arsenic removal from copper ores and concentrates through ...

Arsenic dissolution as a function of leaching time for enargite ore (sample (5)) with arsenic content of 8.32 wt.% and that of sample (5 + 2) blended mixture with arsenic content at 3.0 wt.%. Pulp density of mix sample was increased to 1000 g/L and leaching was conducted at 80 °C.

Adsorption and Removal of Arsenic(Ⅴ) from the Solution by ...

： The orthogonal test is used to study the effect of the reaction conditions for oxalic acid modifying manganese ore on the latter's arsenic(Ⅴ) adsorptive capacity.It is concluded that the optimal reaction conditions for the modification are:oxalic acid dosage of 2.0 mmol/g,dosage of potassium permanganate of 1.0 mmol/g,sulfuric acid concentration of 1.0 mol/L and reaction time of 60 ...

Chapter 1. Source and behaviour of arsenic in natural waters

Arsenic is perhaps unique among the heavy metalloids and oxyanion-forming elements (e.g. arsenic, selenium, antimony, molybdenum, vanadium, chromium, uranium, rhenium) in its sensitivity to mobilisation at the pH values typically found in groundwaters (pH 6.5–8.5) and under both oxidising and reducing conditions.

ore arsenic iron

How to Remove Arsenic, Antimony & Bismuth from Copper. Feb 06, 2017· The copper, insoluble in water, that is in the calcined ore, is removed by the use of tower liquors, and under the action of this solvent a considerable proportion of the arsenic, antimony and bismuth that remained in the calcined ore is also dissolved.

Dissolution of arsenic minerals mediated by dissimilatory ...

We demonstrated that the isolated strains (i) produce metabolites that promote dissolution of minerals, (ii) are resistant to dissolved arsenic compounds, (iii) are able to use the dissolved arsenates as terminal electron acceptor, and (iv) are able to remove arsenic under anaerobic conditions from As-containing copper ore concentrates and ...

Arsenic mineral dissolution and possible mobilization in ...

1. Introduction. Arsenic is chemically classified as a metalloid, having properties of a metal and a non-metal. It is widely distributed in the nature and is commonly associated with the ores of copper, lead, gold, sulfur and iron, .Also it is distributed among a great variety of mineral species, where some of them are naturally occurring, such as arsenopyrite (FeAsS), realgar (As 4 S 4), and ...

Dissolution of Arsenic Minerals Mediated by Dissimilatory ...

The aim of this study was characterization of the isolated dissimilatory arsenate reducing bacteria in the context of their potential for arsenic removal from primary arsenic minerals through reductive dissolution. Four strains, Shewanella sp. OM1, Pseudomonas sp. OM2, Aeromonas sp. OM4, and Serratia sp. OM17, capable of anaerobic growth with As (V) reduction, were isolated from …

Arsenic - Wikipedia

When heated in air, arsenic oxidizes to arsenic trioxide; the fumes from this reaction have an odor resembling garlic. This odor can be detected on striking arsenide minerals such as arsenopyrite with a …

What Mobilizes Arsenic in Ground Water?

The site on Cape Cod, Massachusetts, where USGS scientists conducted experiments on the transport of arsenic in ground water. The experiment consisted of injecting a solution of ground water (from the extraction well) with dissolved arsenic added into the subsurface through an injection well.

How to Remove Arsenic, Antimony & Bismuth from Copper

The copper, insoluble in water, that is in the calcined ore, is removed by the use of tower liquors, and under the action of this solvent a considerable proportion of the arsenic, antimony and bismuth that remained in the calcined ore is also dissolved. This increases the proportion of these elements that is already present in the tower liquors.

Method for removing arsenic and antimony from copper ore ...

The dissolution of arsenic from the ore is assumed to follow the equation 2Cu 2 AsS 4 + 3S = 2AsS 4.tbd. + 3Cu 2 S (2) which shows that 1.5 moles of sulfide are required per mole of arsenic.

Alkaline Oxidative Leaching of Gold-Bearing Arsenopyrite …

arsenopyrite dissolution were determined using cyclic voltammetry and chronocoulometry. Initial arsenopyrite dissolution occurred at -0.20 V versus standard hydrogen electrode (SHE) in a sodium hydroxide (Na0H) solution. Leaching of a high-grade arsenopyritic ore containing, in percent, 28.2 As,

How Does Arsenic Get into the Groundwater? - Arsenic ...

The conditions that favour arsenic dissolution (becoming dissolved in the water) and mobilization (movement with the groundwater to your tap) depend on the circumstances. One thing that is certain is that it takes more than just high arsenic concentrations in the soil or rocks of a region.

Arsenic removal from copper ores and concentrates through ...

A much higher rate of arsenic dissolution is achieved for a lower pulp density at 100 g/L (S/As = 61), but at a very high sulfur/arsenic ratio of 61. Up to 80% arsenic dissolution is achieved within 30 min and complete removal of arsenic is achieved in 3 h.

Arsenic.An environmental problem limited by solubility*

Arsenic.An environmental problem limited by solubility* M.Clara F.Magalhães‡ Department of Chemistry, University of Aveiro, P-3810-193 Aveiro, Portugal Abstract: Arsenic is a toxic element for animals and the majority of plants, in spite of evi-dence that it is also an essential element. The long-term intake of small doses of arsenic has

Effect of arsenic-antimony mineral on cyanide leaching_

Arsenate and thioarsenate in solution can form a covering film on the surface of gold and silver, which hinders the dissolution of gold and silver. Therefore, arsenic-bearing ore is difficult to be leached directly by cyanidation, which is usually treated by oxidation roasting and then cyanide leaching.

(PDF) Modified Hematite Iron for Removing Arsenic(V) from ...

Hematite a cheap indigenous iron ore was found very efficient for the adsorption of arsenic .Nearly 95 % As (V) was adsorbed using 4 g/L adsorbent dose optimum pH range 5–6.5. The column study ...

The Management of Arsenic in the Mining Industry | Request …

Dissolved arsenic in reducing porewaters both precipitates in-situ as secondary sulphides, and diffuses upwards into the overlying lake waters. ... Native arsenic is an occasional ore mineral in ...

THE OXIDATION AND DISSOLUTION OF ARSENIC-BEARING …

A concentrations élevées de bicarbonate et de carbonate, il est possible de mobiliser l'arsenic à partir des surfaces de l'oxyhydroxyde de fer pour le réintroduire dans la solution à cause du bilan des charges à sa surface; cet oxyhydroxyde peut bien aussi capter …

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