The influences of condensation and evaporation area ratio, crystallization temperature and stirring rate were investigated on the concentration of the ammonia water resulting from ammonia tail gas condensation in the process of APT crystallization. The results shows that both lower crystallization temperature and faster stirring rate can increase ammonia concentration of the recovered solution from crystallization ammonia tail gas .When the condensation and vaporization area ratio is 3.9 and the crystallization tempetature is 110, the total ammonia concentration of the recovered solution is 9.9 mol/L.

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Ammonium paratungstate(APT) is a white crystalline salt of ammonium and tungsten, with the chemical formula (NH4)10(H2W12O42)·4H2O.

APT calcined in air change course: T ≥ 240 ℃, as ammonium metatungstate (AMT)300 ~ 350 ℃, ammonium tungsten bronze ATB.400 ℃, the hexagonal WO3.
500 ℃, triclinic crystalline tungsten trioxide.

APT purity, crystalline of hereditary. Calcination temperature, speed has a significant impact on the physical and chemical properties of the product. The higher the calcining temperature, the more coarse particle size obtained WO3.Rapid heated, larger specific surface area. Slowly heated, perfect crystalline, smaller specific surface area.

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According to Arrhenius theory, using the method of nucleation period integral mean rate, the apparent activation energy of ammonium patatungstate (APT) crystal growth is calculated as 94.657KJ/mol. At the same time, the relational expression between APT crystal growth rate constant and temperature is concluded as kn=8.46*10¹⁴ exp (-94657/RT). The results show that the increasing rate of APT nucleation rate is bigger than of APT crystal growth rate as temperature increasing and the granularity of crystal product is fine.

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The research on ammonia dissolving after thermal dissociation and direct ammonia dissolving shows that APT solid is thermally dissociated for 50 minutes at temperature of 280±5℃, and then 1:3 ammonia solution of 200 mL is added to dissolve for 6 hours at temperature of 95℃, leaching efficiency is 85.1%. Dissociation time has a little influence on S (Fe)/WO3. Leaching efficiencyof ammonia dissolving after thermal dissociation is higher than that of direct ammonia dissolving, but amounts of S ( Fe ) / WO3are basically similar.

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A series of WO3 catalysts were obtained through pyrolysis of ammonium paratungstate under different O2/Ar at 700℃. The catalysts were identified by XRD, XPS, DRS measurements, and the photo catalytic activity of WO3 for O2 evolution was studied. The results indicate that with the increasing content of Ar, the oxygen vacancies of WO3 catalysts are increased, the photo catalytic activity for O2 evolution is advanced and the photo catalytic activity of WO3 obtained in pure Ar is the highest. The influence of Fe2+ on photo catalytic activity for O2 evolution was also investigated. The results show that the activity of WO3 is restrained by Fe2+in the photo catalytic reaction with Fe3+as electron acceptor.

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The new process of calcine for ammonium paratungstate to tungsten trioxide by microwave was investigated. The results of experiment show that the maximum decomposing rate of ammonium paratungstate is 96 .67 % after 4 min bymicrowave heating. In the new calcining process, the primary influnce factor is ammonium paratungstate' s weight, the secondary factors are time and microwave power. In this experiment range, the optimum conditions are that the microwave power is 650 W, the calcining time is 4 min, and the ammonium paratungstate′s weight is 10g .

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Matches usually start from 501 in competition darts but other common starts are 301, 401, 701, and even 1001. Sometimes darts matches are played where a “double” is required to start each “Leg” of the match. However, the most common form of play is “straight start” which means that players/teams can begin to score points immediately with the first darts game thrown. Both teams start on the agreed starting number and the object is to score down to zero as quickly as possible. The value of the different sectors of the dartboard can be seen in Fig 1. above. Each section or “leg” of the match must be finished with a “double”, this means the outer scoring ring. For example as one approaches the end of a “leg” a player or team may have 40 points left to score. This means Double 20 is required and to end the “Leg” a dart must be thrown into the “double” section of the “20” sector. Should the thrower miss “double” 20 and hit (for example) a single 1, the the thrower would require 39 to win the “leg” where a single 7 then “double” 16 could be an option. Another example could be the player or team require 51 points. Then there would be several alternatives to end the “leg”. The usual route would be either a single 11 and then “double” 20, or perhaps a single 19 and then “double” 16. The first player or team to hit the required “double” wins the “leg”. A new leg is then started and the procedure repeated until one of the players or teams has won the required number of “legs” to win darts game.

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A game of darts always starts, and ends, with a handshake.

A game of darts can be played in played in several forms. The most common forms are:- One player against another which is known as “Singles” or teams of two players per team which is known as “Doubles” or “Pairs”. A game of darts is played over an agreed number of sections which are known as “legs”. The number of “legs” in a game is always an odd number usually 1, 3, 5, or 7 “legs”. Matches are played as (for example) “Best of 5 “legs”. This means that the first player or team to win 3 “legs” win the match.

Players throw alternately in “Singles” matches. In “Doubles” or “Pairs” matches each “Pair” throws alternately with each player in the respective “Pair” also throwing alternately. A “Throw” consists of “3” darts. If a player completes the “Leg” or the match in less than three darts the remaining dart or darts gameare not thrown.

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It should not rush into buying a set of darts. The weight and shape of darts varies enormously, as do the shapes of the flights.

We recommend that you try as many different types of darts and flights as possible before making a purchase. After a while you will soon become aware that each different type of dart behaves differently when YOU throw it. Take your time, find a set that you feel comfortable with before you buy.

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Dart caring need to keep the needle tip dart degrees.

First, dart beneath the blanket has a certain area of the pad or other cushioning material, so when racing game, dart needle or damage the floor.

Second, the target ring long metal darts in use carom, may loosen, just to nail nailed to move one position.

Third, the paper target darts have various reasons such as climate, there will be some cracks are normal and do not affect the results.

Fourth, sisal darts, in the humid climate, use hair dryer to dry the target surface, to maintain a certain dry to prevent mildew. If mildew occurs. Hair brush can be useful to the stain, wipe clean with alcohol, then blow dry, do not affect the results.

Fifth, keep the needle tip dart degrees, pull the dart, the barb, which will damage the target surface, the impact dartboard life otherwise.

Six, dart bar, dart feathers, dart needle is wearing parts, consumables, dart caring for use when replacing the need to press models, specifications with purchase.

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