35 Matching Annotations
  1. Jan 2020
    1. Chemically, europium’s reactions are similar to calcium. It is used in some superconductor alloys and in television screens, where it produces the red color.

      europium has been popularly used for the red flash and light in smart phones.

    1. Europium is used in the printing of euro banknotes. It glows red under UV light, and forgeries can be detected by the lack of this red glow.

      When they scan a bill they are looking for the europium flash.

    2. In 1901, Eugène-Anatole Demarçay carried out a painstaking sequence of crystallisations of samarium magnesium nitrate, and separated yet another new element: europium.
    3. Low-energy light bulbs contain a little europium to give a more natural light, by balancing the blue (cold) light with a little red (warm) light.
    4. A soft, silvery metal that tarnishes quickly and reacts with water.
    1. White phosphorus is a waxy, transparent solid. Its melting point is 44.1°C (111°F) and its boiling point is 280°C (536°F). It has a density of 1.88 grams per cubic centimeter. If kept in a vacuum, it sublimes if exposed to light.

      the properties of Phosphorus.

    1. somewhere at the interfaces between the solder balls and the nickel-phosphorous pad. Solders are ductile tin-based materials, but during soldering they chemically react with the solid metals being soldered — such as the nickel-phosphorous alloy — to form intermetallic compounds.

      How Phosphorus is used in a smartphone.

    1. Alloys[edit] Antimony forms a highly useful alloy with lead, increasing its hardness and mechanical strength. For most applications involving lead, varying amounts of antimony are used as alloying metal. In lead–acid batteries, this addition improves plate strength and charging characteristics.[49][59] For sailboats, lead keels are used as counterweights, ranging from 600 lbs to over 8000 lbs; to improve hardness and tensile strength of the lead keel, antimony is mixed with lead between 2% and 5% by volume. Antimony is used in antifriction alloys (such as Babbitt metal),[60] in bullets and lead shot, electrical cable sheathing, type metal (for example, for linotype printing machines[61]), solder (some "lead-free" solders contain 5% Sb),[62] in pewter,[63] and in hardening alloys with low tin content in the manufacturing of organ pipes. Other applications[edit] Three other applications consume nearly all the rest of the world's supply.[48] One application is as a stabilizer and catalyst for the production of polyethylene terephthalate.[48] Another is as a fining agent to remove microscopic bubbles in glass, mostly for TV screens;[64] antimony ions interact with oxygen, suppressing the tendency of the latter to form bubbles.[65] The third application is pigments.[48] Antimony is increasingly being used in semiconductors as a dopant in n-type silicon wafers[66] for diodes, infrared detectors, and Hall-effect devices. In the 1950s, the emitters and collectors of n-p-n alloy junction transistors were doped with tiny beads of a lead-antimony alloy.[67] Indium antimonide is used as a material for mid-infrared detectors.[68][69][70]

      Potential uses in phone batteries and silicon wafers As semi conductors.

    1. Lead isotopes are the end products of each of the three series of naturally occurring radioactive elements.

      lead is radioactive, so when you touch it, it can effect your body.

    1. Crushed minerals are extracted with hydrochloric acid or sulfuric acid, which converts the insoluble oxides into soluble chlorides or sulfates. The acidic filtrates are partially neutralized with caustic soda to pH 3–4. Thorium precipitates as its hydroxide, and is then removed. The remaining solution is treated with ammonium oxalate to convert rare earths into their insoluble oxalates. The oxalates are converted to oxides by heating. The oxides are dissolved in nitric acid that excludes one of the main components, cerium, whose oxide is insoluble in HNO3. The solution is treated with magnesium nitrate to produce a crystallized mixture of double salts of gadolinium, samarium and europium. The salts are separated by ion exchange chromatography. The rare-earth ions are then selectively washed out by a suitable complexing agent.[
    1. Most of the antimony mined each year comes from China, which supplies over three-quarters of the world’s total. The remainder is from Russia, South Africa, Tajikistan, Bolivia, and a few other countries, including the United States. Some antimony is produced as a by-product of smelting ores of other metals, mainly gold, copper and silver, in countries such as the United States, Canada, and Australia.

      Top antimony producing countries

    1. Antimony is rarely found in its native (as an element) state. Instead, it usually occurs as a compound. The most common minerals of antimony are stibnite, tetrahedrite, bournonite, boulangerite, and jamesonite.

      How antimony is found in nature

    2. Antimony is a moderately active element. It does not combine with oxygen in the air at room temperature. It also does not react with cold water or with most cold acids. It does dissolve in some hot acids, however, and in aqua regia. Aqua regia is a mixture of hydrochloric and nitric acids. It often reacts with materials that do not react with either acid separately.

      Chemical properties of antimony

    3. Antimony is a silvery-white, shiny element that looks like a metal. It has a scaly surface and is hard and brittle like a non-metal. It can also be prepared as a black powder with a shiny brilliance to it. The melting point of antimony is 630°C (1,170°F) and its boiling point is 1,635°C (2,980°F). It is a relatively soft material that can be scratched by glass. Its density is 6.68 grams per cubic centimeter.

      Physical properties of antimony

    1. Occupational exposure may cause respiratory irritation, pneumoconiosis, antimony spots on the skin and gastrointestinal symptoms. In addition antimony trioxide is possibly carcinogenic to humans.

      Negative health effects of repeated exposure to antimony

    1. Antimony is used in the electronics industry to make some semiconductor devices, such as infrared detectors and diodes. It is alloyed with lead or other metals to improve their hardness and strength. A lead-antimony alloy is used in batteries. Other uses of antimony alloys include type metal (in printing presses), bullets and cable sheathing. Antimony compounds are used to make flame-retardant materials, paints, enamels, glass and pottery.

      Uses of antimony in technology

    1. europium are crucial to your iPhone’s function – they’re used in the phone’s battery, as well as to help give the display screen colour and make the phone vibrate when you get a text,

      Needed for normal function in Iphone.

    1. Lanthanum mainly is obtained from lanthanum-rich monazite and bastnasite. Other lanthanum-bearing minerals include allanite and cerite. It is mined in the USA, China, Russia, Australia, and India.

      This is where Lanthanum is mined and where it comes from in the mines

    1. a relatively poor conductor of electricity

      lead is a poor electricity conductor but good and used in phone batteries.

    1. Drift mining utilizes horizontal access tunnels, slope mining uses diagonally sloping access shafts, and shaft mining utilizes vertical access shafts. Mining in hard and soft rock formations require different techniques.

      So different kinds of mining use different tunnel systems, how do we decide which kind is best in each situation?

    1. Environmental impacts of mining can occur at local, regional, and global scales through direct and indirect mining practices.
  2. May 2019
    1. the government reported the discovery of large gold deposits in Lege Dimbi, also in Sidamo.

      This shows that there was gold in Ethiopia!

    1. Developing economies’ copper demand has steadily grown over the last decades, fueling economic and social improvement. By 2011, China already represented 40% of the demand.

      Why does China need so much.

    2. Codelco is a state-owned Chilean mining company and the world’s largest copper producer. Based on their annual report and USGS statistics, they produced ~10% of the world’s copper in 2015 and own 8% of global reserves. They are also a large producer of greenhouse gas emissions. Last year, Codelco produced 3,2 t CO2e/millions tmf from both indirect and direct effects, and in 2011 it consumed 12% of the total national electricity supply.

      Goddamn they should start recylcling

    1. Neodymium is chiefly obtained from monazite and bastnasite, where it occurs as an impurity. It is mined in the USA, China, Russia, Australia, and India.

      some info about the ore and where it is mined

    1. The Neodymium metal element is initially separated from refined Rare Earth oxides in an electrolytic furnace. The "Rare Earth" elements are lanthanoids (also called lanthanides) and the term arises from the uncommon oxide minerals used to isolate the elements

      how neodymium is refined

    1. Although few in number, the multinational mining companies that are earning billion-dollar profits in Zambia have had a massive impact on its environment and people.
    1. The metal is a solid material and metallic gray in color. Furthermore, the metal possess high melting and boiling points. At standard temperature and pressure, cobalt is not readily oxidized, which means it does not easily lose electrons from its surface.

      A description of cobalt.

    2. cobalt can be found among the d-block elements, transition metals. It has the chemical abbreviation Co and atomic number 27.

      Where to find cobalt on periodic table and cobalt's atomic number.

    1. Monseigneur de Hemptinne watched Yeke people working at Dikuluwe as late as 1924. They worked in the dry season and stopped when the first rains arrived. The mining camp was near a stream where millet could be planted. Women and children collected malachite from the surface, while men used iron picks to excavate pits and shafts, using fire to crack the rocks when needed. The mines were between 10 metres (33 ft) and 15 metres (49 ft) deep with galleries up to 20 metres (66 ft) long. The ore would be sorted and then taken to a nearby stream for concentration before being smelted

      info about how mines work

    2. The Katanga, or Shaba, copperbelt in the DRC is a belt about 70 kilometres (43 mi) wide and 250 kilometres (160 mi) long

      how large the coperbelt is

    1. Xiamen Tungsten and Xiamen Sanhong Molybdenum would invest more than 2 billion yuan (US$314.13 million) in the surveying and subsequent exploitation of the tungsten ore mine.
    2. The proved reserve of the mine has exceeded Jiangxi's total amount of available tungsten reserves, and has a potential economic value of more than 300 billion yuan (US$47.13 billion).