Bayer process during the production of alumina Inorganic Amendments for the Remediation of Cadmium-Contaminated Soils

mud reagents

Red Mud

Red mud is a product of the Bayer process during the production of alumina (Hairi et al., 2015). As the temperature and pressure increases, the solubility of red mud decreases with sodium hydroxide (Nie et al., 2016). Its composition depends upon its parent material from which it is produced (Liu and Wu, 2012). It is present in the form of slurry having 10–30% solid materials (Milačič et al., 2012). Its pH ranging from 10.67 measured by Italian standard soil analysis 1:2.5 ratio and also has greater ionic strength (Hua et al., 2017).

Chemical analysis revealed that it contains silica, iron, calcium, titanium, and aluminum, and has minimal concentrations of elements such as sodium, potassium, chromium, nickel, zinc, copper, etc. Moreover, its chemical composition is given as follows:

Red mud is composed of minerals such as hematite, gibbsite, calcite, quartz, goethite, diaspore, rutile, kaolinite, etc. (Wang and Liu, 2012) measured using an X-ray diffractometer. The specific weight of red mud is 2.77 gcm – 3 measured by a gas pycnometer. According to the particle size distribution, it is a very fine material and has a high surface area (Wang and Liu, 2012).

Red mud has a greater sorption capacity than any other inorganic addition because it has a large amount of hydroxides that are used in the adsorption and precipitation mechanism to remove Cd from water, and it has a large amount of Al and Fe oxides (Wang et al., 2008a). At low pH, red mud works well in removing Cd from the soil (Liu et al., 2011). Cd is more available at low pH; red mud raises the pH and stabilizes the pH due to this Cd adsorption, which increases and decreases the bioavailability of Cd (Worden et al., 2009). The use of red mud to decontaminate Cd is therefore an effective and environmentally friendly technique (Panda et al., 2017).

Mud Reagents
Mud Reagents

Anthropogenic Impacts

Though a colossal amount of red mud was discarded into the GOC for over half a century, effects on local marine food webs are unknown. Environmental concerns caused by disposal of red mud relate to its high alkalinity and sodicity (Paramguru et al., 2005; Power et al., 2011) and its documented hazards to sea life (Blackman and Wilson, 1973; Dauvin, 2010; Dethlefsen and Rosenthal, 1973; Pagano et al., 2002). Because red mud is a valuable resource that can be reused (e.g. Paramguru et al., 2005; Pontikes and Angelopoulos, 2013), systematic dumping of millions of tonnes at sea, let alone within a semienclosed Gulf such as the GOC, is not only hazardous but also wasteful.

High levels of metals were found in seagrass (Posidonia oceanica) from the Bay of Antikyra (Malea et al., 1994), an area where levels of polycyclic aromatic hydrocarbons in sediments, and concentrations of polychlorinated biphenyls (PCBs) and dichlorodiphenyl trichloroethane and its metabolites (DDTs) in Mediterranean mussels (Mytilus galloprovincialis) were among the highest sampled throughout Greece (Botsou and Hatzianestis, 2012; Tsangaris et al., 2010, 2011). In the present study, distribution modelling showed no strong correlation between red mud deposits and dolphin occurrence.

Because striped dolphins tend to be epi- and mesopelagic feeders and red mud dumping impacts predominantly the seafloor, avoidance would not be expected. However, indirect effects such as contamination up the food web are possible (Jepson et al., 2016). Bottlenose dolphins are primarily benthic feeders, and thus any use of the area is likely to result in direct and indirect exposure to toxic contaminants, with unknown health effects.

 

 

Cadmium Iodate

C00370 100G
EUR 501.27

Cadmium borate

C00110 20G
EUR 173.57

Cadmium iodide

GRM1354-100G 1 unit
EUR 51.11
Description: Cadmium iodide

Cadmium iodide

GRM1354-500G 1 unit
EUR 229.86
Description: Cadmium iodide

Cadmium cyanide

C00190 1G
EUR 193.5

Cadmium formate

C00330 25G
EUR 118.95

Cadmium sulfide

C00600 100G
EUR 244

Cadmium Chloride

06613-42 25G
EUR 14

Cadmium Chloride

06613-71 1G
EUR 9.8

Cadmium chromate

C00180 100G
EUR 308.91

Cadmium fluoride

C00305 25G
EUR 150.78

Cadmium Selenide

C00550 10G
EUR 146.55

Cadmium selenite

C00560 5G
EUR 143.27

Cadmium Chloride

C059000 5g
EUR 64
Description: 10108-64-2

Cadmium Sulphate

C059020 5g
EUR 58
Description: 10124-36-4

Cadmium sebacate

T30683-10mg 10mg Ask for price
Description: Cadmium sebacate

Cadmium sebacate

T30683-1g 1g Ask for price
Description: Cadmium sebacate

Cadmium sebacate

T30683-1mg 1mg Ask for price
Description: Cadmium sebacate

Cadmium sebacate

T30683-50mg 50mg Ask for price
Description: Cadmium sebacate

Cadmium sebacate

T30683-5mg 5mg Ask for price
Description: Cadmium sebacate

Cadmium sulphide

GRM4104-25G 1 unit
EUR 142.05
Description: Cadmium sulphide

Cadmium Molybdate

C00430 100G
EUR 252.74

Cadmium Phthalate

C00510 1G
EUR 277.7

Cadmium telluride

C00620 10G
EUR 161.94

Cadmium Tungstate

C00640 5G
EUR 196.97

Cadmium Zirconate

C00650 100G
EUR 213.78

cadmium electrode

ISE22B ea
EUR 422.4

Cadmium carbonate

GRM365-500G 1 unit
EUR 39.95
Description: Cadmium carbonate

Cadmium telluride

GRM4674-10G 1 unit
EUR 271.42
Description: Cadmium telluride

Cadmium perchlorate

C00500 25G
EUR 66.63

Cadmium Bar, 99.999%

GX4807-250 250
EUR 361.7

Cadmium Metasilicate

C00420 10G
EUR 235.32

Cadmium rods 99.99%

C00071 100G
EUR 679.1

Cadmium Shot 99.999%

C00072 50G
EUR 173.93

Cadmium borotungstate

C00120 5G
EUR 233.46

Cadmium Monocarbonate

C595033 10g
EUR 58
Description: 513-78-0

Cadmium oxide, 99.999%

GX5303-100 100
EUR 449.7

Cadmium oxide, 99.999%

GX5303-25 25
EUR 182.5

Cadmium oxide, 99.9%

GX6089-100 100
EUR 113.1

Cadmium Stannate_x000D__x000D_

C00570 100G
EUR 707.7

cadmium orthophosphate

20-abx186402
  • Ask for price
  • Ask for price
  • 25 g
  • 5 g

Cadmium iodide 99%

C00380 25G
EUR 92.6

Cadmium iodide, 99%

GX5272-250 250
EUR 387.8

Cadmium Acetylacetonate

C00090 50G
EUR 368.13

Cadmium carbonate_x000D__x000D_

C00150 25G
EUR 192.91

Cadmium oxalate 98%

C00480 100G
EUR 911.6

Cadmium acetate 97%

C00080 100G
EUR 261.9

Cadmium dimethyl 97%

C00250 5G
EUR 2001.72

Cadmium stearate 90%

C00580 100G
EUR 197.2