Composite tungsten electrode applied in welding, which is the same with other tungsten electrode. But they are different in welding industry. Since composite tungsten electrode owns slightness arc, big compression degree, the dissolves depth is biggest during welding at middle and big electric current, they are mainly used to war and aerospace industry.

Composite tungsten electrode in electrochemical catalyzed hydrogen evolution
Composite tungsten electrode can improve the electmehemical catalyzed hydrogen evolution of cobalt electrode. Cobalt – composite tungsten electrode was developed, and its property of electrochemical catalyzed hydrogen evolution can be showed by means of cathodic polarization curves, a. c. impedance technique and SEM. Compared with cobalt electrode, Cobalt tungsten electrode has rough surface, high exchange current density and smaller resistance of hydrogen evolution reaction. But composite tungsten electrode is clean and grounded that superior to cobalt electrode in electrochemical catalyzed hydrogen evolution. Thus, composite tungsten electrode are better choice in electrochemical catalyzed hydrogen evolution.

 

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Under the lower confining pressure, the velocity of broken volume decrease is faster. However, when confining pressure reaches a certain degree, the decrease scope reduces. With the number of pore increasing, aperture, depth and broken volume will decrease by the rising confining pressure. Different numbers of pores have different sensitivity to confining pressure. On one hand, too many pores will make each flow has little energy, smaller impact area and shorter spraying distance.

On the other hand, the ductility of rocks will promote with the increasing confining pressure, which turns brittle fracture into plastic collapse and all of them will increase the threshold pressure of jet-flow for cracking rock. Therefore, reducing pores appropriately under high confining pressure is beneficial for improving the efficiency of rock cracking.















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Confining pressure refers to the isobaric stress state, which the three main stresses is equal at any point. It is also known as hydrostatic pressure or hydrostatic pressure and also called static rock pressure or geostationary pressure in the earth. The drilling confining pressure generally refers to the stress, which works uniformly on the horizontal of the rocks. In rock mechanics test, the major part is to test surrounding fluid pressure. In oil well drilling engineering, the horizontal stress after decomposability is called confining pressure. Some related experimental statistics shows that with the increasing confining pressure, the broken volume of rocks is decreasing, and the cracking ability of single-hole nozzle is better than porous nozzle.

















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Halvers tungsten dart rule is a fun game for 2 players or teams.

The Object: To get a higher score than the other team.

The Scoring: One player from each team throws at bulls-eye, closest to the bulls-eye plays first.

The Play: Each team throws three darts to try and attain the highest score based on the target listed in the scoreboard each round. The rounds are played in order listed on the scoreboard and only the targets described for that particular round count. The thin outer "doubles" ring counts as two times the number hit and the thin inner "triples" ring counts as three.

The rounds 20, 19, 18, 17, 16, 15, 14, 25 and 50 mean to aim for the number specified. For example during the 20's round only darts in the 20 count, etc. 25 means single bulls ONLY, doubles do not count. 50 means double bulls ONLY, singles do not count.

The remaining rounds are as follows:
T = Triples round, any triples count.
D = Doubles round, any doubles count.
3C = 3 Colors round. Each dart must land in a different COLOR on the board.
H = Hurdles round. The first dart is thrown anywhere on the board and the next darts must "hurdle" a number clockwise. For example, the first dart is thrown into the 20, the next dart has to hit the 18 to count and the next dart has to hit the 13 to count. These darts must be in order.

If all three darts miss the target number, your previous score is cut in half, hence the name of the game. For example, in the first round you throw two single-20's for a score of 40. In the next round, you miss the 19's, your total score would now be 20.

Strategy: Be careful when you get to the 25 & 50 sections of the game, those bulls can be elusive and missing them can quickly kill a big lead!
 

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High Score tungsten dart rule is a very simple game for any number of players. It is very popular among soft-tipped dart players. It is also one of the few games in this list that may be played on an electronic board.

The Object: To be the first to reach a predetermined score, usually 1000.

The Scoring: Players' names are written across the top of the board in order and the board is divided into columns for each player's score. Order is usually determined by each player throwing one tungsten dart at bulls-eye; closest to the bulls-eye throws first, furthest throws last.

The Play: Each player takes turns trying to score the highest points with three tungsten darts. The thin outer "doubles" ring counts as two times the number hit and the thin inner "triples" ring counts as three times the number hit.

Play begins at zero and the total of the player's three tungsten darts is added to the previous total each round. First player to reach the target score wins the game.

NOTE: The score does not have to end on exactly the target score as it does in x01.

Strategy: Shoot lots of triple-20's or triple-19's.

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Tungsten darts is a fun game that can be played alone or in a group. There are hundreds of tungsten dart games that can be played for fun, though some people do it professionally for a profit. No matter how expensive or sturdy your dartboard is, if you have soft-tip darts, occasionally those tips are going to break off into the board. If you don't clear those tips out, they can prevent tungsten darts from sticking properly in the board. It is best to remove the broken tip out of the dartboard as soon as possible. The instructions of how to remove the broken tungsten dart tip out of dartboard:

1. Pull the tip out with a dartboard repair tool, if available. The tip of the tool makes it easy to grip the broken tip and pull it out because it has an edge specifically made for this one task.

2. Grip the broken tip with a pair of needle-nose pliers if you don't have a special dartboard repair tool. If the broken tip is at least 1/8th of an inch long, this should be easy to remove with the pliers.

3. Push the broken tip through the surface of the dartboard if it is less than 1/8th of an inch thick. There is a small gap between the board and the scoring wedges that allows for tiny tips like these to fall through without a problem.

4. Unfold one end of a paper clip and use the tip to gently remove the broken tungsten dart tip from the dartboard. This is the way to go if you don't have a special dartboard repair tool and also don't have a pair of needle-nose pliers handy.

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Cut throat is a variety of cricket, a popular and fun tungsten dart game. Whether or not you are already familiar with the rules of cricket, if you follow the steps below you will soon be an expert at cut throat--at the rules at least. Steps about how to play Cut Throat in tungsten darts are as followed:

1. Decide upon your strategy. In cricket, each player works toward getting three marks in each number 15 through 20, as well as the bulls-eye. A double counts as two marks and a triple as three. Once a player got three marks for number, that number is "closed." You will want to work toward closing all your numbers in whatever manner best suits your style of play.

2. Keep score of your hits. Traditionally this is done with a chalkboard hung near the dartboard. An electronic dartboard will often take care of this for you. If you do have to score on your own, the traditional manner in which to do so is to write the numbers down the side of the board and the names of the players (or teams) at the top. The first hit of any number is designated by a diagonal line under the name and in line with the number. With the second hit this diagonal line is turned into an X. Finally, for the third hit, draw a circle around the X.

3. Determine who goes first and begin the game, alternating turns with each player taking three shots at a time. Record any hits accordingly.

4. Try not to hit any number once you have closed it. This is the key to cut throat. In other styles of cricket, hitting a number you have closed is desirable, as it gives you points and you need the most points--in addition to closing out every number--to win. In cut throat, however, you do not want to score points because instead of earning them yourself they are given to any opponent who has not also closed out the number.

5. Record any points scored and remember that once every player (or team) has closed out a particular number no more points can be scored by hitting it. For example, if all players have closed the 20 and you hit it, no points are accrued.

6. Score more points than your opponent(s) to win and you must close out all the numbers 15-20, as well as the bulls-eye.

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Scoring tungsten darts can seem overwhelming at first, but will make more sense once you understand the layout of the board. A round dartboard features 20 sections. The particular section a tungsten dart hits dictates what score you receive. The most common tungsten darts game is called 501, which involves bringing your score from 501 down to zero quicker than your opponent. A scorekeeper keeps track of points scored in each round and how many points you have remaining on a board that’s visible at all times.

The DartBoard
A dartboard is 17.75 inches in diameter and is separated into 20 different sections. Each of these sections is separated with thin metal wires. Around the far edges of the board are numbers, ranging from one to 20. Just inside the numbers is a thin section made of wire that’s referred to the double ring. There is another thin section made of wire further in toward the center of the circle that’s referred to as the triple ring. At the center of the board are the outer and inner bulls-eyes, different-sized circles created with the thin wire.

Scoring By the Numbers
Where your tungsten dart hits on the board influences what score you receive. Tungsten darts that land within the larger sections but not within the double, triple or bulls-eye sections, receive a score equal to that particular section’s number. For example, a tungsten dart landing in this larger area of a section assigned with a point value of 14 receives a score of 14. If the tungsten dart lands within the double section, it earns double points. If a dart lands within the triple section, it earns triple points. Tungsten darts that land within the outer bulls-eye receive 25 points and tungsten darts that land within the inner bulls-eye score 50 points. A tungsten dart that hits outside the wire or doesn’t stick into the board scores a zero.

Example: Playing 501
In the game of 501, both players begin with a score of 501. The goal is to get the score down to zero before your opponent. Each player throws three darts per round with the intention of scoring as many points as possible. For example, if you hit 25, 50 and 12, your score that round would be 87. The highest score possible in a round is 180, which is achieved by hitting the triple twenty with all three darts. After you’re finished with your round, your opponent gets to throw three darts. To win the game, not only do you need to bring your score down to exactly zero, but you have to hit your tungsten dart within the double section with your final tungsten dart. If you fail to hit a double or end up with a score below zero, your opponent gets to go and you have to wait for your next turn.

Keeping Track of Scores
A scorekeeper who is not participating in the game keeps track of the score. For 501, a scoreboard or sheet of paper is typically posted on a nearby wall. The scoreboard is split into two pairs of two columns, with each pair of columns assigned to a player. In each player’s left column, the scorekeeper keeps track of a player’s score for each round. The space in the right column is used to keep track of the countdown from 501. For example, if you scored 87 on your first round, the scorekeeper would write 87 at the top of the left column and 414 at the top of the right column. If you then scored 100 on your second round, the scorekeeper would write 100 just below 87 in the left column and then 313 just below 414 at the top of the right column.

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Recycling

Recycling is an important factor in the world’s tungsten supply. It is estimated that today some 30% is recycled, and the tungsten processing industry is able to treat almost every kind of tungsten-containing scrap and waste to recover tungsten and, if present, other valuable constituents.

Contaminated cemented carbide scrap, turnings, grindings and powder scrap are oxidized and chemically processed to APT in a way similar to that used for the processing of tungsten ores. If present, cobalt, tantalum and niobium are recovered in separate processing lines. Other tungsten containing scrap and residues might require a modified process.

Clean cemented carbide inserts and compacts are converted to powder by the zinc process (treatment with molten zinc which is dissolved in the cobalt phase and is then distilled off, leaving a spongy material which is easily crushed). This powder is added back to the manufacture of ready-to-press powder. By this process, not only tungsten carbide but also cobalt, tantalum carbide and other carbides are recycled.

Recycling of tungsten in high speed steel is high, and a typical melt contains 60 to 70% scrap, including internally generated scrap.

On the other hand, recycling in such applications as lamp filaments, welding electrodes and chemical uses is low.

Although tungsten seems to be relatively harmless to the environment, environmental concerns have led to an increasing recycling rate, especially when the material contains other metals in addition to the tungsten. Recycling is always more environmentally friendly and usually more economic than waste disposal.

 

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Mining & Beneficiation

Tungsten is usually mined underground. Scheelite and/or wolframite is frequently located in rather narrow veins which are slightly inclined and often widen with the depth. Open pit mines exist but are rare.

Most tungsten ores contain less than 1.5% WO₃ and ore dressing plants are always in close proximity to the mine.

The ore is first crushed and milled to liberate the tungsten mineral crystals.

Scheelite ore can be concentrated by gravimetric methods, often combined with froth flotation, whilst wolframite ore can be concentrated by gravity, sometimes in combination with magnetic separation.

Pricing

The average annual price of tungsten since 1950 has fluctuated between a nadir of US $10 per metric ton unit in 1963 and a peak of US $175 in 1977. During the last five years, trade in concentrates has diminished and the market has relied more and more upon the APT quotation as a price guide since APT is the product traded in the largest quantity. Prices are mainly based on the quotations published twice a week by London’s "Metal Bulletin", although other trade journals also publish quotations or indicative prices.

Processing Concentrates

Most tungsten concentrates are processed chemically to ammonium paratungstate (APT). Secondary raw materials like (oxidized) scrap and residues are another important feed for chemical tungsten processing.

Wolframite concentrates can also be smelted directly with charcoal or coke in an electric arc furnace to produce ferrotungsten (FeW) which is used as alloying material in steel production.

Pure scheelite concentrate may also be added directly to molten steel.

 

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