User:GrostoTwig/sandbox

Bayer Process Notes

Original Article: https://en.wikipedia.org/wiki/Bayer_process Note from Notepad

-Extraction conditions need to be better explained. (Dependent on alumninum condition)

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-Equation kind of general. May need to expand on which element is.

-History of process is really short.

--Probably talk about Bayer more

-There was a change in the process mentioned and expanding that would be beneficial I think. Mentioned in the Talk section. The guy that mentioned it provided sources so I'll use it.

-The second to last paragraph contradicts what the guy with the source said about it going through modifications. "CO2 no longer used industrially"

-Go into red mud waste management

RED MUD is everywhere in other sources

Dangers of the process in 2010 I think (I'll call it the Danube River Incident not on the Wiki though)

"60 manufacturing operations using Bayer Process" found in Red Mud Wiki article. Its also kinda dangerous to the environment. Alkilinity. Can kill people and contaminate the environment.

Talk about finding use for the waste product (aka Red Mud)

Source 1 - 1.9-3.6 tonnes of bauxite required to produce 1 tonne of alumina - temps up to 270 degrees

• majority of aluminum in the ore is dissolved
• gibbsite is precipitated after solid separation

-Under this point in the source goes intohow - Verify the source's equations with the ones found on the Wikipedia article -Wikipedia article doesn't mention the Bayer process liquors (liquids used in the process) many sources have used this word -Alakaline (ph>14) have organic compounds

         -(polybasic acids, polyhydroxy acids, alcohols, and phenols) reason for deep red color, and strong smell

-organic matter accumulates as it enters the process stream

       -major organic elements exit through the red mud circuit, with gibbsite, using techniques for removing organic material
            -shown in the 2nd step

-Gibbsite (Al(OH)₃)- Precipitation of crystalline gibbsite from caustic aluminate solutions

     -shown in the 3rd equation (2 Al(OH)3 → Al2O3 + 3 H2O)
     -Essentially, the main "product" that would lead to the real product
     -Formation favored at higher temperatures (~70 C) 

-Organic impurities on the precipitation of gibbsite, cause high gibbsite impurity content, liquo and gibbsite colouration, caustic losses and increased solution viscosity and density -The organic impurities on the precipitation of gibbsite can cause high gibbsite impurity content, liquor and gibbsite colouration, caustic losses and an increase in the solutions viscosity and density.

-Red Mudd produced during the digestion of bauxite with sodium hydroxide.

   - Most common irons: goethite (α-FeOOH) and haematite (α-Fe2O3)
   - higly alkaline with surface area and contains a lot of chemical and mineralogical species so it can make a large negative effect on the environment.

Waste

Red mud is the waste product that is produced in the digestion of bauxite with sodium hydroxide. It has high calcium and sodium hydroxide content which makes a complex chemical composition. This makes it very toxic and a possible source of pollution. The amount produced during the process is nothing to overlook. The amount warranted scientist and refiners to find a use for it, which turns out is good for ceramics.

(https://www.epa.gov/radiation/tenorm-bauxite-and-alumina-production-wastes) Red mud dries into a fine powder that contains iron, aluminum, calcium and sodium. It becomes a health risk when Some plants use the waste to produce aluminum oxides. In the United States, the waste is disposed in a large impoundment, a sort of reservoir created by a dam. The impoundments are typically lined with clay or synthetic liners. The US does not approve of use for the use of the waste due to the dangers it risks to the environment. The EPA identified high levels of arsenic and chromium in some red mud samples.

Some countries in the European Union use red mud in their building materials. The European Union has an index of Naturally Occurring Radioactive Materials (NORM), which judges the content of various building materials. The materials on this index are minerals and raw materials that contain radionuclides. (http://www.world-nuclear.org/information-library/safety-and-security/radiation-and-health/naturally-occurring-radioactive-materials-norm.aspx)

Ajka Alumina Plant Accident

On October 4, 2010, the Ajka alumina plant in Hungary had an incident where the western dam of its red mud reservoir collapsed. The reservoir was filled with 700,000m^3 of a mixture of red mud and water with a pH of 12. The mixture was released into the valley of Torna river and flooded parts of the city of Devecser and the villages of Kolontár and Somlóvásárhely. The incident resulted in 10 deaths, more than a hundred injuries, and contamination in lakes and rivers.

History

The industrial success of this process caused it to replace the Le Chatlier process which was used to produce alumina from bauxite.

The engineering aspects of the process were improved upon to decrease the cost starting in 1967 in Germany and Czechoslovakia.This was done by increasing the heat recovery and using large autoclaves and precipitation tanks. To more effectively use energy, heat exchangers and flash tanks were used and larger reactors decreased the amount of heat lost. Efficiency was increased by connecting the autoclaves together so that the operation is more automated.

Nitpicks

After Intro first line -"Bauxite ore is a mixture of..."

Add Link to "pressure vessel" to the wikipedia article explaining what it is

Add Link to "gibbsite" to the wikipedia article for gibbsite

Add link to "autoclave"

Links 1. https://www.sciencedirect.com/science/article/pii/S0927775798007985 2. https://www.sciencedirect.com/science/article/pii/0304386X96000096 3. https://patents.google.com/patent/US4046855A/en 4. http://www.scs.illinois.edu/~mainzv/HIST/bulletin_open_access/num17-18/num17-18%20p15-19.pdf