Free to follow every thread. No paywall, no dead ends.
Manganese: the story on HearLore | HearLore
Manganese
Manganese is the 12th most abundant element in the Earth's crust, yet for most of human history, it remained an invisible force shaping civilization from the shadows. Ancient cave painters in Gargas, France, used manganese dioxide as a pigment to create their art 30,000 years ago, long before anyone understood the element itself. The name manganese derives from the Greek word magnes, which originally referred to two distinct black minerals found in the region of Magnesia. One was the male magnes, known today as magnetite, which attracted iron and gave us the word magnet. The other was the female magnes, which did not attract iron but was used to decolorize glass. Glassmakers in the 16th century called this female ore manganesum, a corruption of the original name, and it was from this substance that the metal was eventually isolated. The story of manganese is one of mistaken identity and slow recognition, where a material essential to modern steel production was once dismissed as a nuisance in glassmaking. The element was first isolated in 1774 by Johan Gottlieb Gahn, a Swedish chemist who reduced manganese dioxide with carbon. Before this discovery, manganese was merely a tool for glassmakers, used to remove the green tint caused by iron impurities in glass. The transition from a glassmaking additive to a critical industrial metal took over a century, and even then, its importance was not fully appreciated until the 19th century. The history of manganese is a testament to the slow pace of scientific discovery, where a single element could remain hidden in plain sight for millennia, waiting for the right moment to change the world.
The Silent Guardian of Life
Manganese in the form of the deep violet salt potassium permanganate is commonly used in laboratories as an oxidizer. Potassium permanganate is also used as a biocide in water treatment. Solutions of potassium permanganate were among the first stains and fixatives to be used in the preparation of biological cells and tissues for electron microscopy. Manganese dioxide, which is abundant in nature, has long been used as a pigment. The cave paintings in Gargas that are 30,000 to 24,000 years old are made from the mineral form of MnO2 pigments. Manganese compounds were used by Egyptian and Roman glassmakers, either to add to, or remove, color from glass. Use as glassmakers soap continued through the Middle Ages until modern times and is evident in 14th-century glass from Venice. Ignatius Gottfried Kaim and Johann Glauber discovered that manganese dioxide could be converted to permanganate, a useful laboratory reagent. By the mid-18th century, the Swedish chemist Carl Wilhelm Scheele used manganese dioxide to produce chlorine. Scheele and others were aware that pyrolusite, the mineral form of manganese dioxide, contained a new element. Johan Gottlieb Gahn isolated an impure sample of manganese metal in 1774, which he did by reducing the dioxide with carbon. The manganese content of some iron ores used in Greece led to speculations that steel produced from that ore contains additional manganese, making the Spartan steel exceptionally hard. Around the
Johan Gottlieb Gahn isolated manganese metal in 1774 by reducing manganese dioxide with carbon. This discovery occurred after manganese had been used for centuries as a glassmaking additive to remove green tints caused by iron impurities.
What ancient civilization used manganese dioxide as a pigment 30000 years ago?
Ancient cave painters in Gargas, France used manganese dioxide as a pigment to create art 30000 years ago. These cave paintings from the period between 30000 and 24000 years old are made from the mineral form of manganese dioxide pigments.
How much manganese is contained in ocean floor nodules?
Manganese nodules found on the ocean floor are composed of 29% manganese. According to a 1978 estimate, the ocean floor contains 500 billion tons of these manganese nodules.
Who first described the neurological disorder manganism in 1837?
British academic James Couper first described manganism in 1837 after studying two patients who were manganese grinders. The disorder presents with symptoms resembling Parkinson's disease but is not responsive to L-DOPA treatment.
What was the real mission of the Hughes Glomar Explorer in 1972?
The real mission of the Hughes Glomar Explorer was to raise a sunken Soviet submarine known as K-129 to retrieve Soviet code books. The ship used a cover story about harvesting manganese nodules from the sea floor to hide this operation.
beginning of the 19th century, manganese was used in steelmaking and several patents were granted. In 1816, it was documented that iron alloyed with manganese was harder but not more brittle. In 1837, British academic James Couper noted an association between miners' heavy exposure to manganese and a form of Parkinson's disease. In 1912, United States patents were granted for protecting firearms against rust and corrosion with manganese phosphate electrochemical conversion coatings, and the process has seen widespread use ever since.
An abundant resource of manganese is in the form of manganese nodules found on the ocean floor. These nodules, which are composed of 29% manganese, are located along the ocean floor. The environmental impacts of nodule collection are of interest. According to 1978 estimate, the ocean floor has 500 billion tons of manganese nodules. Attempts to find economically viable methods of harvesting manganese nodules are still ongoing, however, none has been commercialized. In 1972, the CIA's Project Azorian, through billionaire Howard Hughes, commissioned the ship Hughes Glomar Explorer with the cover story of harvesting manganese nodules from the sea floor. This cover story triggered a rush of activity to collect manganese nodules. The real mission of Hughes Glomar Explorer was to raise a sunken Soviet submarine, the K-129, with the goal of retrieving Soviet code books. Manganese also occurs in the oceanic environment, as dissolved manganese, which is found throughout the world's oceans, 90% of which originates from hydrothermal vents. Particulate Mn develops in buoyant plumes over an active vent source, while the dissolved Mn behaves conservatively. Mn concentrations vary between the water columns of the ocean. At the surface, dissolved Mn is elevated due to input from external sources such as rivers, dust, and shelf sediments. Coastal sediments normally have lower Mn concentrations, but can increase due to anthropogenic discharges from industries such as mining and steel manufacturing, which
The Purple Alchemist's Secret
enter the ocean from river inputs. Surface dissolved Mn concentrations can also be elevated biologically through photosynthesis and physically from coastal upwelling and wind-driven surface currents. Internal cycling such as photo-reduction from UV radiation can also elevate levels by speeding up the dissolution of Mn-oxides and oxidative scavenging, preventing Mn from sinking to deeper waters. Elevated levels at mid-depths can occur near mid-ocean ridges and hydrothermal vents. The hydrothermal vents release dissolved Mn enriched fluid into the water. The dissolved Mn can then travel up to 4,000 kilometers due to the microbial capsules present, preventing exchange with particles, lowering the sinking rates. Dissolved Mn concentrations are even higher when oxygen levels are low. Overall, dissolved Mn concentrations are normally higher in coastal regions and decrease when moving offshore.
Manganese overexposure is most frequently associated with manganism, a rare neurological disorder associated with excessive manganese ingestion or inhalation. Historically, persons employed in the production or processing of manganese alloys have been at risk for developing manganism, however, health and safety regulations protect workers in developed nations. The disorder was first described in 1837 by British academic John Couper, who studied two patients who were manganese grinders. Manganism is a biphasic disorder. In its early stages, an intoxicated person may experience depression, mood swings, compulsive behaviors, and psychosis. Early neurological symptoms give way to late-stage manganism, which resembles Parkinson's disease. Symptoms include weakness, monotone and slowed speech, an expressionless face, tremor, forward-leaning gait, inability to walk backwards without falling, rigidity, and general problems with dexterity, gait and balance. Unlike Parkinson's disease, manganism is not associated with loss of the sense of smell and patients are typically unresponsive to treatment with L-DOPA. Symptoms of late-stage manganism become more severe over time even if the source of exposure is removed and brain manganese levels return to normal. Chronic manganese exposure has been shown to produce a
The Ocean Floor's Hidden Treasure
parkinsonism-like illness characterized by movement abnormalities. This condition is not responsive to typical therapies used in the treatment of PD, suggesting an alternative pathway to the typical dopaminergic loss within the substantia nigra. Manganese may accumulate in the basal ganglia, leading to the abnormal movements. A mutation of the SLC30A10 gene, a manganese efflux transporter necessary for decreasing intracellular Mn, has been linked with the development of this Parkinsonism-like disease. The Lewy bodies typical to PD are not seen in Mn-induced parkinsonism. Animal experiments have given the opportunity to examine the consequences of manganese overexposure under controlled conditions. In non-aggressive rats, manganese induces mouse-killing behavior. Waterborne manganese has a greater bioavailability than dietary manganese. According to results from a 2010 study, higher levels of exposure to manganese in drinking water are associated with increased intellectual impairment and reduced intelligence quotients in school-age children. It is hypothesized that long-term exposure due to inhaling the naturally occurring manganese in shower water puts up to 8.7 million Americans at risk. However, data indicates that the human body can recover from certain adverse effects of overexposure to manganese if the exposure is stopped and the body can clear the excess.