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Posts Tagged ‘beryl’

The second part of the video on beryllium is now finished. You can watch it here:

This video has literally been 2 1/2 years in the making; my students Amy Zirbes and Nathan Jane videotaped our interview with subject expert Phil Sabey, the Manager of Technology and Quality at the Delta mill, in NOvember, 2007. This video discusses the history of mining beryllium at the mine site in the Spor Mountains of western Utah, including how the bertrandite deposit was discovered, and the land rush that occurred as a result (including an incident involving Maxie Anderson, who was head of Ranchers and the general counsel for Anaconda. Maxie Anderson went on to be one of three men to first cross the Atlantic in a helium balloon in 1978). This video also shows how bertrandite it is mined today by Brush Engineered Materials using open pit mines, then transported and processed at the concentration plant near Delta, Utah. The concentrated beryllium hydroxide is then shipped by rail to Elmore, Ohio for final refining into beryllium metal, alloys, and ceramics products. This episode also discusses Chronic Beryllium Disease, the main health hazard of refining or working with beryllium.

Chronic Beryllium Disease:

Beryllium dust, when in the air in concentrations of greater than 2 micrograms per cubic meter, gets inhaled and irritates the lung alveoli. The body treats it as an invading body, and sends white blood cells which surround the beryllium particle and form small granules called granulomas in the lungs. At this point, a person is said to have sub-clinical CBD or is “sensitized” to beryllium. Most people who are sensitized do not develop clinical CBD, but in about 2-5% of sensitized people, the immune system overreacts and the granulomas build up to where the lungs become stiff and respiratory function is impaired, leading to symptoms similar to pneumonia. There is no cure once CBD has set in, and the eventual result is painful death.

Before the effects of beryllium dust were known, a high number of workers in the beryllium industry were getting sick, especially in certain plants such as the old Brush Wellman plant in Lorain, Ohio. Beryllium in its ores (beryl crystals and bertrandite) is tightly bound to the crystal lattice and is therefore harmless. But refining bertrandite or beryl means that the beryllium is physically and chemically separated from the crystal, resulting in fine beryllium particles getting into the air unless precautions are taken. The effects of beryllium disease were well enough known by the mid-1960s that when the Delta concentration plant was built, safeguards were put in place that reduce beryllium dust to under 0.2 micrograms per cubic meter of air, or less than 10% of the maximum safety levels. Workers also wear respiratory equipment such as facemasks with filters to prevent even that level of dust from entering their lungs. There has not been any incident of chronic beryllium disease in the workers at the Delta plant.

Final beryllium metal, alloys, and ceramics are also fairly safe as the beryllium is part of the metal and not airborne. The danger occurs when these materials are cut, machined, or milled, which allows beryllium particles to get into the air where they can be inhaled. The only way to cure chronic beryllium disease is to avoid it in the first place by preventing beryllium dust from entering the air. Special precautions must therefore be taken in any business that handles beryllium. OSHA has been studying CBD and is likely to be coming out with new and even stricter standards soon.

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After weeks of editing and tweaking, I have completed the first half (part 1) of the video on Beryllium. This section is on the uses and sources of beryllium, and the geology of the bertrandite deposit of western Utah. The second half will take another week or so (I have quite a few tight deadlines on client projects that must be completed right now) and will include the history of mining, current mining operations, refining, and hazards. Here is Part 1:

Beryllium Part 1

I am including here the script for the section on sources of beryllium:

Sources of Beryllium

Beryllium is the first member of the alkaline earth family of elements, which means that it’s highly reactive and easily bonds to form compounds but is difficult to separate into a pure metal. Beryllium was discovered by Louis-Nicolas Vauquelin in 1798 as a component of beryl and in emeralds. Friedrich Wöhler and Antoine Bussy independently isolated the metal in 1828 by reacting potassium with beryllium chloride. Beryllium’s chemical similarity to aluminum was probably why beryllium was missed in previous searches. We now know that beryllium is found in only a few minerals, including the beryl family and bertrandite.

Emerald necklace

Emerald necklace in the National Museum of Natural History

Beryl is a hexagonal crystal of beryllium aluminum cyclosilicate that can have various colors depending on impurities. Trace amounts of chromium or sometimes vanadium give it a deep green color; when crystallized slowly into a transparent crystal, it is called emerald. Emeralds have been prized as gemstones for thousands of years; today, the main source of emeralds is Columbia in South America.

Heliodor and Aquamarine

Heliodor and Aquamarine at the National Museum of Natural History

Trace amounts of iron (II) ions produce a blue-green variety of beryl called aquamarine. Small amounts of iron (III) ions produce shades of beryl from golden yellow to greenish yellow called heliodor. Manganese (II) impurities produce pink beryl called morganite. Completely pure beryl is colorless and is called goshenite.

Morganite and heliodor

Morganite and Heliodor

The rarest form of beryl is red beryl, mined only in the Wah Wah Mountains of southwestern Utah. It gets its color from traces of manganese (III) and is a deeper red than morganite. In addition to these gem varieties of beryl, there is non-gem beryl, which is opaque and considered semi-precious. It is chiefly mined in Brazil in the Minas Gerais District although some deposits exist in Colorado and New England as well; it is New Hampshire’s state mineral. A large specimen 5.5 meters by 1.2 meters was found in a quarry in Maine, and the largest crystal ever found is a beryl crystal from Madagascar that is 18 meters long and 3.5 meters in diameter.

Red Beryl and Emerald

Red Beryl and Emerald, from the collection of Keith and Mauna Proctor

Bertrandite, on the other hand, is a pinkish mineral consisting of hydrous beryllium oxide silicate that doesn’t form very large crystals. It tends to be found clinging to grains of igneous pegmatites such as granite. The bertrandite in the Spor Mountains of western Utah is found in highly altered rhyolite and is the only deposit large enough and concentrated enough to mine commercially. It is the sole source of beryllium for all of the United States.

Bertrandite and Beryl

Bertrandite and Beryl, on display at Brush Resources Delta Plant

Beryllium is also found in a few other rare minerals, such as chrysoberyl (beryllium aluminum oxide), phenakite (beryllium silicate), euclase (hydrous beryllium aluminum silicate), hambergite (hydrous beryllium borate), and beryllonite (sodium beryllium phosphate).

Phenakite Euclase and Beryllonite

Phenakite, Euclase, Hambergite, and Beryllonite

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Topaz-Spor Mountain area

Topaz-Spor Mt. area

I am continuing this series of posts on the sources, mining, and refining of beryllium ore. I am in the middle of editing the interview my students did in Dec., 2007 of Phil Sabey at the Brush Resources’ Delta Concentration Mill and will have the final videos done by next week. Today I’ve been creating a series of Flash animations showing the geologic history of the Spor Mountain area where the bertrandite deposits are located. Today’s post will be on the refining process used at the Delta Mill to concentrate the bertrandite and beryl ore into beryllium hydroxide.

Bertrandite and Fluorspar

Fluorspar with Bertrandite

Refining Beryllium Ore

With only 0.65 % beryllium oxide (or 4.5 lbs. per ton of beryllium) in the final ore, a process had to be engineered to economically concentrate the beryllium for final processing. The properties that make beryllium useful also make it difficult to extract from its ores. Robert Maddox, Howard Gimperline, Jack Valliquet, Richard Shank, and other chemical engineers at Brush Wellman’s plant in Elmore, Ohio in the early 1960’s devised a unique solvent extraction process. With refinements, the process was seen to be economical and the go-ahead was given to build a concentration plant as close to the mine and to railroad transportation and a good water source as possible. In Dec., 1967 a groundbreaking ceremony was held at the mine and in April, 1968 a ceremony was also held at the mill site north of Delta, Utah. By the end of 1969, the plant was producing its first beryllium hydroxide concentrate.

Process for refining bertrandite

Process for Refining Bertrandite Ore

The solvent extraction process removes the beryllium by first crushing and wet grinding the ore in a ball mill, then leaching it with sulfuric acid and steam in rotating tanks at 95 ° C to dissolve the beryllium. Thickening agents are added which help to settle the sludge in a series of flotation tanks while leaving the beryllium sulfate in solution. The sludge is stirred by counter current decantation and pumped from tank to tank as the dissolved beryllium sulfate is washed over the side to continue the process. The remaining sludge is finally discarded to a tailings pile.

Sulfation Tanks

Sulfuric Acid and Steam are added to the bertrandite to dissolve the beryllium

The beryllium is then separated from the sulfate using an organic compound, then stripped from the organic by ammonium carbonate. Impurities of iron and aluminum are removed through steam hydrolysis, which leaves the beryllium in the form of beryllium hydroxide, which is vacuum drum filtered. Since beryllium dust is toxic, this entire process must be done in a sealed system, including the final packaging of the beryllium hydroxide into blue drums for shipment.

Panorama of the Brush Resources plant

Panorama of the Brush Resources Beryllium Plant

There are a lot of impurities in the bertrandite ore; some that gave problems early on were the high sodium content, the high uranium content, and the zirconium. The leftover filtrate still has appreciable quantities of uranium, so it is pumped to evaporation ponds, then shipped elsewhere for final uranium processing.

Beryl crystals

Beryl Crystals Ready for Refining

Once it was proven that this process could compete economically with the beryl extraction process already being used, the go-ahead was given to build the Utah processing plant. A site was selected near the Union Pacific railroad tracks and the Sevier River north of Delta and south of Lynndyl in west central Utah. The plant was completed in 1969 and began processing ore that had already been mined and stockpiled. Brush Wellman was awarded the prestigious J. C. Vaalor Award for Chemical Engineering in 1970 for the implementation of this process. In 1978, an addition was built on the plant to allow the processing of beryl ore, making the Delta plant the only facility in the United States that processes either form of beryllium ore. When beryllium was identified by the U. S. government as a strategic metal for its critical uses in the aerospace industry, beryl ore was purchased from mines in Brazil and stockpiled. Brush Resources has now purchased this strategic stockpile and is extracting the beryllium from it.

Pouring molten frit

Pouring Molten Beryl Frit

To recover beryllium from beryl crystals, the crystals must first be destroyed, since the beryllium is tightly bound in the beryl crystal lattice. The beryl is melted at 1700 ° C in a furnace, then quenched rapidly in water to break the crystal lattice and turn the beryllium particles into a frit, with the non-beryllium materials removed as slag. The frit is heat-treated at 1000 ° C in a rotary kiln, ground up in a ball mill, and leached with steam and sulfuric acid at 325 ° C in a rotating drum to dissolve the beryllium. This solution is added to the bertrandite solution in the flotation tanks to continue the process. In 1980, additional flotation tanks were added to accommodate the beryl solution.

Heat treater kiln

All of these processes require careful control and monitoring to improve yields and ensure safety. Using a Continuous Improvement Process, the Delta plant has added computer automation controls and improved laboratory analysis. New flocculent agents and organic solvents have improved the extraction yields, and the plant now processes ore at a 99% efficiency level. Around 400 tons of bertrandite and about 10 tons of beryl ore can be processed per day at the Delta plant.

Special thanks go to Phil Sabey for the tour of the Brush Resources plant and for providing the brochures, Powerpoint presentations, and photos upon which this post is based.

Phil Sabey in Chem Lab

Phil Sabey in Analysis Lab

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The next videos that will be completed for the Elements Unearthed Project are two episodes on the sources, mining, refining, and uses of beryllium. I’ve written a few posts previously about this topic, and as I continue to organize and prepare materials to use in the videos (which will be edited over the next week), I have created several diagrams that describe the process used for surveying and developing open pit mines at the Brush Resources’ Spor Mt. mine site in western Utah. You might say, “Beryllium? Why should I care about some rare metal that I’ll never use in my lifetime?” But you’d be surprised. You are already using beryllium (for example, the electrical contacts inside the automatic windows of your car use a beryllium-copper alloy because it can handle frequent changes in heat and resists corrosion better than many other alloys). Beryllium is also an essential metal for medical, nuclear power, and aerospace applications. I’ll discuss more of beryllium’s uses and its refining and sources in a later post, but in this post let’s talk about how the bertrandite ore is mined.

Spor Mt. beryllium deposits

Location of Bertrandite in Western Utah

Mining Operations at Brush Resources

The bertrandite ore found in the Spor Mts. is very similar to clay (an aluminum silicate) and looks like common dirt except it has a slight pinkish color. It’s also associated with fluorspar or fluorite, which is often a deep blue to violet color. One is tempted to think the more colorful fluorite is the mineral we want, but it’s actually the crumbly pink coating found on the fluorite nodules. Elsewhere in the Spor Mts., the fluorite has been mined commercially.

The first attempt at mining the bertrandite ore was started by Anaconda on their claim. They tried hard rock mining, but the soft altered rhyolite of the ore body proved too dangerous to mine that way.  One day, while the miners were all having lunch, the mine caved in. Fortunately no one was hurt, but it was determined then that the only safe method was open pit mining.

Exploratory drilling

Exploratory core drilling

Potential mine sites are surveyed by drilling core samples every 100 feet to map out the general location of the ore bodies. The bertrandite deposits in the Spor Mts. are located in a mineralized zone of altered rhyolite tuff that overlies a bedrock of limestone. This soft and crumbly altered layer is overlaid by a tough, hard layer of unaltered rhyolite with about the same composition and hardness of granite. All of this is further overlaid by a layer of gravel, loose rock, and sand deposited by Lake Bonneville during the last ice age. Since the ore body is tilted, it occasionally reaches the surface (where it was originally discovered) and in other places dips so far below ground as to be unfeasible to mine. Several mine sites, such as the Blue Chalk and Roadside I sites have already been mined, but enough reserves have been mapped to last at least 50 more years at current production levels.

Planning an Open Pit Mine

Planning an Open Pit Mine

Once the location of the ore body has been generally mapped out, mining engineers plan out an open pit structure that will reach the ore with the least disturbance to the overlying layers while keeping the sides of the pit terraced to safely prevent rockslides and excessive erosion. Once the plan is approved, a contractor is hired to remove the overburden, usually in the winter and spring months. The loose alluvial gravel and soil is removed first and set aside for later reclamation. The hard rhyolite is blasted and removed, and the altered rhyolite layer is also removed to within about seven feet of the bertrandite ore.

Removing the Overburden

Removing the Overburden

A second phase of core drilling is carried out, with holes every 25 feet to more accurately map out the exact ore locations. For a typical ore body, between 40 and 60,000 cores are drilled and sampled every two feet. 3D structural maps are prepared to identify where various grades of ore are located. The ore is then removed carefully; a technician with a portable field berylometer walks before the bulldozer and stakes out the locations of the ore grades that are being removed; a self-loading scraper scoops up the ore and moves it to stockpiles where it is sorted by grade into the same pile. The ore is then transported by 18-wheeler to the processing plant near Delta, Utah, about 50 miles southeast. High-grade ore is mixed with low-grade ore so that all the bertrandite coming to the plant has about the same percentage of beryllium. The final ore has less than .65% beryllium, or about four pounds per ton.

Next Post: Refining Beryllium Ore

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