Uranium tile
Encyclopedia
Uranium tiles have been used in the glazing
industry for many centuries, as uranium oxide
makes an excellent ceramic glaze
, and is reasonably abundant on the earth's crust.
Not long after Henri Becquerel
discovered radioactivity in uranium salts, Madame Curie discovered both polonium
and radium
as two new radioactive elements also present with uranium.
The relatively high specific activity
and moderate half-life
of 1,600 years of Ra-226, the main radioisotope of radium found in uranium ore, made for a material which when mixed with a phosphor
allowed for a glow-in-the-dark substance.
Thus, in addition to its medical usage, radium usage also became a major industry in the 1920s and 1930s for making watch, clock and aircraft dials. The radium dial painters brought a certain degree of notoriety to the abuse of radioactive materials, and that precautions needed to be followed with this new substance.
Because it takes approximately 3 metric tons of uranium to extract 1 gram of Ra-226, prodigious quantities of uranium were mined to sustain this new industry. The uranium ore itself was a "waste product" of this industry. By some estimates, nearly one million tons of uranium were mined to support this industry.
Taking advantage of this now abundant resource, the tile and pottery glazing industry now had a relatively inexpensive and abundant source of glazing material that produced a wide variety of colors depending upon admixtures, firing, etc.
Vibrant colors of orange, yellow, red, green, blue, black, mauve, etc. were produced on tiles and other ceramic materials, and by some estimates, some 25% of all houses and apartments constructed during that period [circa 1920-1940] used varying amounts of bathroom or kitchen tiles that had been glazed with varying amounts of uranium. These can now be readily found in older homes, apartments, and other buildings still standing from that era by use of a simple geiger counter
that readily detects the beta radiation emitted by uranium's ever-present decay chain
radio-daughters.
In most situations, the radiation exposure is not excessive, but there are some exceptions in which pure uranium oxide [which produces red-orange coloration as a glaze] on bathroom floors can pose a hazard for infants crawling around for hours on end, day after day.
Glazing
Glazing, which derives from the Middle English for 'glass', is a part of a wall or window, made of glass. Glazing also describes the work done by a professional "glazier"...
industry for many centuries, as uranium oxide
Uranium oxide
Uranium oxide is an oxide of the element uranium.The metal uranium forms several oxides:* Uranium dioxide or uranium oxide * Uranium trioxide or uranium oxide...
makes an excellent ceramic glaze
Ceramic glaze
Glaze is a layer or coating of a vitreous substance which has been fired to fuse to a ceramic object to color, decorate, strengthen or waterproof it.-Use:...
, and is reasonably abundant on the earth's crust.
Not long after Henri Becquerel
Henri Becquerel
Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity along with Marie Curie and Pierre Curie, for which all three won the 1903 Nobel Prize in Physics.-Early life:...
discovered radioactivity in uranium salts, Madame Curie discovered both polonium
Polonium
Polonium is a chemical element with the symbol Po and atomic number 84, discovered in 1898 by Marie Skłodowska-Curie and Pierre Curie. A rare and highly radioactive element, polonium is chemically similar to bismuth and tellurium, and it occurs in uranium ores. Polonium has been studied for...
and radium
Radium
Radium is a chemical element with atomic number 88, represented by the symbol Ra. Radium is an almost pure-white alkaline earth metal, but it readily oxidizes on exposure to air, becoming black in color. All isotopes of radium are highly radioactive, with the most stable isotope being radium-226,...
as two new radioactive elements also present with uranium.
The relatively high specific activity
Specific activity
In nuclear sciences and technologies, "activity" is the SI quantity related to the phenomenon of natural and artificial radioactivity. The SI unit of "activity" is becquerel, Bq, while that of "specific activity" is Bq/kg. The old unit of "activity" was curie, Ci, while that of "specific activity"...
and moderate half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of 1,600 years of Ra-226, the main radioisotope of radium found in uranium ore, made for a material which when mixed with a phosphor
Phosphor
A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness , and fluorescent materials, where the emission decay takes place over tens of nanoseconds...
allowed for a glow-in-the-dark substance.
Thus, in addition to its medical usage, radium usage also became a major industry in the 1920s and 1930s for making watch, clock and aircraft dials. The radium dial painters brought a certain degree of notoriety to the abuse of radioactive materials, and that precautions needed to be followed with this new substance.
Because it takes approximately 3 metric tons of uranium to extract 1 gram of Ra-226, prodigious quantities of uranium were mined to sustain this new industry. The uranium ore itself was a "waste product" of this industry. By some estimates, nearly one million tons of uranium were mined to support this industry.
Taking advantage of this now abundant resource, the tile and pottery glazing industry now had a relatively inexpensive and abundant source of glazing material that produced a wide variety of colors depending upon admixtures, firing, etc.
Vibrant colors of orange, yellow, red, green, blue, black, mauve, etc. were produced on tiles and other ceramic materials, and by some estimates, some 25% of all houses and apartments constructed during that period [circa 1920-1940] used varying amounts of bathroom or kitchen tiles that had been glazed with varying amounts of uranium. These can now be readily found in older homes, apartments, and other buildings still standing from that era by use of a simple geiger counter
Geiger counter
A Geiger counter, also called a Geiger–Müller counter, is a type of particle detector that measures ionizing radiation. They detect the emission of nuclear radiation: alpha particles, beta particles or gamma rays. A Geiger counter detects radiation by ionization produced in a low-pressure gas in a...
that readily detects the beta radiation emitted by uranium's ever-present decay chain
Decay chain
In nuclear science, the decay chain refers to the radioactive decay of different discrete radioactive decay products as a chained series of transformations...
radio-daughters.
In most situations, the radiation exposure is not excessive, but there are some exceptions in which pure uranium oxide [which produces red-orange coloration as a glaze] on bathroom floors can pose a hazard for infants crawling around for hours on end, day after day.