Aluminium in Water - - WHO recognised the beneficial effects of the use of aluminium as a coagulant in water treatment to WHO recognised the beneficial effects of the use of aluminiu[r]
Trang 1GROUP IIIA BORON GROUP
Trang 3ĐẶC ĐIỂM CHUNG
1 CÁC NGUYÊN TỐ KHÔNG GIỐNG NHAU NHIỀU
NHƯ TRONG IIA VÀ IA
2 TÍNH KIM LOẠI TĂNG TUY VẬY CÓ ẢNH HƯỞNG
CỦA CO d VÀ CO f
3 SỐ OXI HÓA CHỦ YẾU LÀ +3 TRỪ B CÒN CÓ SỐ
OXI HÓA +1
4 THẾ ĐIỆN CỰC LỚN HƠN TRONG IIA B KHÔNG
TẠO CATION NÊN KHÔNG XÁC ĐỊNH ĐƯỢC THẾ ĐIỆN CỰC
5 B GIỐNG NHIỀU VỚI Si TRONG IVA HƠN LÀ
GIỐNG VỚI Al
Trang 40.1-0.5 mm ĐỂ BỀN HÓA
ĐIỀU CHỈNH TRONG LÒ HẠT NHÂN
NHẸ-BỀN ĐỂ CHẾ TẠO MÁY BAY
Trang 52 1254 / 2 3
1200 2
o o
C
H kJ mol C
Trang 6The most economically important compounds of boron are:
Sodium tetraborate pentahydrate (Na 2 B 4 O 7 · 5H 2 O), which is used in large amounts in making insulating fiberglass and sodium perborate
bleach.
Orthoboric acid (H 3 BO 3 ) or boric acid, used in the production of textile fiberglass and flat panel displays or eye drops, among many uses
Sodium tetraborate decahydrate (Na 2 B 4 O 7 ·
10H 2 O) or borax , used in the production of
adhesives, in anti-corrosion systems and many other uses.
Trang 75 10 -4 %
nguyên tử/vỏ trái đất
Trang 8Orthoboric acid (H 3 BO 3 ) or boric acid
Tinh thể cấu tạo lớp song song:
liên kết trong lớp là liên kết
hidro, liên kết giữa các lớp là
lực Van de Van tinh thể có
dạng vảy nhỏ, sờ thấy nhờn
Tan trong nước và thu nhiệt (0oC: 1.95 g/l; 100oC:
290 g/l) Dễ kết tinh lại trong nước Bản thân không bay hơi; bay hơi cùng hơi nước.
Trang 12…Aluminium has only been produced
commercially for 146 years and is still a very young metal Mankind has been using copper,
lead and tin for thousands of years and yet today more aluminium is produced than all other non-ferrous metals combined Annual primary production in 1999 was about 24
million tonnes and secondary - recycled -
production to some 7 million tonnes The total
of some 31 million tonnes compares with 14.1 million tonnes of copper , 6.0 million tonnes
of lead and 0.2 million tonnes of tin…
Trang 13TÍNH CHẤT LÝ HỌC
1 Kim loại trắng bạc, cấu trúc lập phương tâm diện Có màng
oxit mỏng bảo vệ Mp 650 oC, Bp 2467 oC.
2 Nhiệt độ thường mềm, dễ kéo dài, dát mỏng làm dây điện,
tụ điện, gói thực phẩm và dược phẩm Từ 100-150 oC dẻo,
dễ chế hóa cơ học Trên 600 oC ròn, dễ nghiền thành bột Lỏng rất nhớt, Mg, Cu làm giảm độ nhớt nên hay có trong hợp kim nhôm.
3 Dẫn điện và nhẹ bằng 0.6 và 3 lần so với Cu.
4 Bề mặt trơn bóng, phản xạ tốt ánh sáng và nhiệt làm
gương kính phản chiếu, ống dẫn dầu thô, bể chứa cách nhiệt.
5 Tạo nhiều hợp kim quan trọng: duyra (94%Al, 4%Cu, 2%Mg,
Mn, Fe, Si) cứng và bền như thép mềm, dùng trong SX otô, máy bay Silumin (85%Al, 10-14%Si, 0.1%Na) bền, dễ đúc để làm động cơ máy bay, tàu thủy.
Trang 14TÍNH CHẤT HÓA HỌC
1 Là kim loại hoạt động do bán kính nguyên tử lớn
hơn B Ở điều kiện thường kém hoạt động do có lớp màng oxit 10 nm rất bền bao bọc.
2 Lá nhôm mỏng cháy trong oxi tỏa nhiều nhiệt.
3 Là chất khử mạnh – phương pháp nhiệt nhôm Hỗn
hợp 25%Fe 2 O 3 +75%Al bột để hàn nhanh chi tiết sắt, khi cháy đạt 2500 o C.
4 Không phản ứng với hidro Phản ứng với halogen,
Trang 18Aluminium in the Air - The commercial aviation industry would never have succeeded without aluminium The Wright brothers' first aeroplane, which flew in 1903, had a four-cylinder, 12-horsepower auto engine modified with a 30-pound aluminium block to reduce weight Strong aluminium alloys take the extraordinary pressures and stresses involved in high altitude flying Wafer thin aluminium panels keep the cold out and the air in Today, there are around 5,300 commercial passenger aircraft flying in the world Aluminium comprises about 80 per cent of an aircraft's unladen weight A Boeing 747 jumbo jet contains around 75,000kg of aluminium The structure of the space shuttle is 90% aluminium.
Rover Aluminium absorbs kinetic energy In a vehicle crash involving a largely aluminium vehicle a high proportion of the shock is absorbed by the structure, not by the vehicle occupants Aluminium does not rust Over the vehicle's life, there will
be a saving of from six to twelve times the energy it takes to produce the primary aluminium used in its construction, every tonne of aluminium which replaces a tonne of traditional heavier materials will save 20 tonnes of carbon dioxide equivalents over the lifetime of the automobile It is estimated that 90 per cent of trailer trucks and long distance buses have aluminium bodies Aluminium components can cut 1,800 kilograms from the weight of a tractor-trailer truck Thus such a truck can carry a bigger load without exceeding weight limits
the "Japanese Bullet Train" all have passenger cars made of aluminium Most modern subway cars and most rail freight cars are also made of aluminium Fast ferries, with speeds of 35-50 knots, built of aluminium are revolutionising transport over short sea routes
Aluminium's resistance to corrosion means it is virtually maintenance-free Its strength and lightness encourage its use in earthquake prone zones New technologies mean solar power captors can be inserted in aluminium frames, thus saving considerable amounts of energy and protecting the environment The majority of aluminium used in buildings will be recycled and can be used over and over again
seven per cent of the heat it receives, leaving 93 percent of the heat to cook your food Using aluminium cookware, you only need a quarter of the energy required to heat stainless steel or cast iron, thus saving on energy bills
beverages Aluminium can be rolled into ultra-thin foils which are light, strong and have unique barrier and insulation qualities to preserve food, cosmetics, pharmaceutical products and protect from ultra-violet light, odours and bacteria Aluminium packages are secure, tamper-proof, hygienic, easy to open and recyclable Aluminium withstands both heat and cold It is easy to sterilise for food and medical applications It's an excellent barrier against liquids, vapours and light It transmits conducted heat, and reflects radiant heat That's why you can oven-bake a potato in foil or insulate your home with it Less than an ounce of aluminium sprayed on a polymer forms a thin insulating sheet that can keep a new born baby warm or save the life of someone on an exposed mountain top
remove unwanted material including several organisms known to cause disease and make tap water drinkable
Trang 201808 Sir Humphry Davy (Britain) established the existence of aluminium and named it.
1821 P Berthier (France) discovers a hard, reddish, clay-like material containing 52 per cent aluminium oxide near the village of Les Baux in southern France He called it bauxite, the most common ore of aluminium.
1825 Hans Christian Oersted (Denmark) produces minute quantities of aluminium metal by using dilute potassium amalgam to react with anhydrous aluminium chloride, and distilling the resulting mercury away to leave a residue
of slightly impure aluminium.
1827 Friedrich Wöhler (Germany) describes a process for producing aluminium as a powder by reacting potassium with anhydrous aluminium chloride.
1845 Wöhler establishes the specific gravity (density) of aluminium, and one
of its unique properties - lightness.
1854 Henri Sainte-Claire Deville (France) improves Wöhler's method to create the first commercial process The metal's price, initially higher than that
of gold and platinum, drops by 90% over the following 10 years The price is still high enough to inhibit its widespread adoption by industry.
1855 A bar of aluminium, the new precious metal, is exhibited at the Paris Exhibition.
1885 Hamilton Y Cassner (USA) improves on Deville's process Annual output 15 tonnes!
Trang 211886 Two unknown young scientists, Paul Louis Toussaint Héroult (France) and Charles Martin Hall (USA), working separately and unaware of each other's work, simultaneously invent a new electrolytic process, the Hall-Héroult process, which is the basis for all aluminium production today They discovered that if they dissolved aluminium oxide (alumina) in a bath of molten cryolite and passed a powerful electric current through it, then molten aluminium would be deposited at the bottom of the bath.
1900 Annual output 8 thousand tonnes.
1913 Annual output 65 thousand tonnes.
1920 Annual output 128 thousand tonnes.
1938 Annual output 537 thousand tonnes.
1946 Annual output 681 thousand tonnes.
1999 Annual output 24 million tonnes.
Trang 22The Bayer process is the principal industrial means of producing alumina, itself important in the Hall-Héroult process for producing aluminum.
Bauxite, the most important ore of aluminum, contains only 60% alumina, Al2O3, the rest being a mixture of silica, various iron oxides, and titanium dioxide The alumina must be purified before
40-it can be refined to aluminum metal In the Bayer process, baux40-ite
is washed with a hot solution of sodium hydroxide, NaOH, at 250°C This converts the alumina to aluminium hydroxide, Al(OH)3, which dissolves in the hydroxide solution according to the chemical equation
-The other components of bauxite do not dissolve and can be filtered out as solid impurities Next, the hydroxide solution is cooled, and the aluminium hydroxide dissolved in it precipitates out as a white, fluffy solid When then heated to 1050°C, the aluminium hydroxide decomposes to alumina, giving off water vapor in the process:
Trang 23960 o C
5V – 140 kA
2 3
Trang 24NHÔM OXIT – Al 2 O 3
Trang 25ĐẶC ĐIỂM
1 Tồn tại dưới 1 số dạng đa hình mà bền hơn cả là dạng
α-corundum và γ.
2 Al2O3-α là tinh thể bao gồm ion O2- xếp sít theo kiểu lục
phương, trong đó 2/3 hổng bát diện là ion Al3+ Không màu, không tan trong nước Tạo thành khi nung ở 1000 oC nhôm hidroxit, muối nhôm hoặc từ phản ứng nhiệt nhôm Có độ bền nhiệt động và cơ học lớn do năng lượng mạng lưới tinh thể ion lớn bao gồm tương tác tĩnh điện giữa các ion và liên kết cộng hóa trị Al3+ với bán kính bé và điện tích lớn có tác dụng cực hóa mạnh với O2- làm các cặp e của O2- chiếm AO p và d của Al3+ Việc chuyển cặp e từ O2- sang Al3+ làm giảm tương tác tĩnh điện nhưng bù lại bằng tương tác cộng hóa trị làm nó
có độ bền đặc biệt.
3 Al2O3-γ là tinh thể lập phương không màu, hoạt động mạnh
hơn corundum, tan trong kiềm và axit, nên không tồn tại trong
tự nhiên
Trang 26ỨNG DỤNG
mài kim loại.
chính xác, chân kính đồng hồ Rubi tạo tia laze rubi cho ứng dụng quang lượng tử.
xúc tác.
tấm lót trong lò điện
Trang 27Industrial Fabrication Process
Aluminium oxide, also known as alumina, is the main component of bauxite, the principal ore of aluminium The largest manufacturers in the world of alumina are Alcoa, Alcan and Rusal Companies which specialise in the production of speciality aluminium oxides and aluminium hydroxides include Alcan and Almatis The bauxite ore is made up of impure Al2O3, Fe2O3, and SiO2 These are then purified by the Bayer Process:
Al2O3 + 3H2O + 2NaOH + heat → 2NaAl(OH)4
The Fe2O3 does not dissolve in the base The SiO2 dissolves as silicate Si(OH)6-6 Upon filtering, Fe2O3 is removed With the addition of an acid, Al(OH)3precipitates The silicate remains in solution Then:
2Al(OH)3 + heat → Al2O3 + 3H2O
The formed Al2O3 is alumina.
In 1961, GE developed "Lucalox", a transparent alumina used in sodium vapor lamps.
In August 2004, scientists in the United States working for 3M developed a technique for making an alloy of aluminium oxide and rare earth elements to produce a strong glass called transparent alumina.
Trang 29Aluminium hydroxide - Al(OH) 3
aluminium in normal conditions As found in nature it is known as the mineral gibbsite Closely related are aluminium oxide hydroxide, AlO(OH), and aluminium oxide, Al2O3, differing only by loss of water These compounds together are the major components of the aluminium ore, bauxite.
The character of 'aluminium hydroxide' has been controversial It
is safe to say that a simple scheme of Al3+ ions and OH- ions is oversimplified More and less hydrated forms are very common Some people write Al2O3 x H2O instead.
Aluminium hydroxide is amphoteric In strongly acid conditions, Al(OH)2+ is formed; in strongly basic conditions, Al(OH)4- is formed These are the main ions in dilute solutions; in concentrated solutions, polymeric ions are formed which can be quite complex.
Salts of the anion Al(OH)4- (or similar, such as AlO2-) are sometimes called aluminates.
Al(OH)3 has a molar mass of 78.01.
When used, aluminum hydroxide neutralizes the excess acid For example, Al(OH)3 + 3HCl yields AlCl3 + 3H2O.