January, 1926
INDUSTRIAL A N D ENGINEERING CHEMISTRY
(6) Obtain standard A. S. T. M. distillation on this stock (c) Obtain desired tests (3) Lamp oil content: ( a ) Charge and run as above until the required grade of gasoline has been distilled off. Then continue until a temperature of approximately 10’ F. below the desired final boiling point of the lamp oil is reached, and cut the distillation ( b ) Obtain desired tests D-Distillation of the tar from B : (1) Charge 250 to 400 cc. in a 500-cc. Hempel distillation flask and distil under 4 em. absolute pressure (2) Make 4 per cent cuts in a Briihl receiver, starting with a temperature of 450’ F. in most cases ( a ) Mix these cuts t o obtain any desired viscosity, and make other desired tests (3) Obtain any desired tests on asphalt residue in the flask
It is realized that this outline is quite general in nature, and probably is capable of modification and improvement in many respects, but it has proved very successful in practice thus far, and is believed to be capable of extensire application. Results of Tests on S o u t h e r n California C r u d e Oils Navy Cold test on Gravity spec’n lubricating stock Lamp (Cor. for gasoline (Medium heavyograde) 011 FIELD % S. & W.) Per cent Per cent ’ F. F. 21.7 +4a Long Beach 8.3 +40 22.4 ... 13.9 ... ... 25.3 21.5 7.5 55 60 26.2 25.3 ... ... 28.9 31.0 ... ... Santa F e Springs 30.6 23.2 ... +65 60 32.7 29 4 17.0 ... 33.4 36.7 34.3 38.8 ... ... ... 36.9 40.2 ... 75 80 Inglewood 13.5 0.7 ... 10 15 17.7 8.4 11.1 - 10 15 19.9 11.0 10 15 22.3 14.5 ... 10 + 5 24.5 19.0 ... +45 +40 Huntington Beach 14.5 3.0 - 5 ... 10 - 5 19.1 4.1 ... 10 15.7 - 5 20.7 11.2 10 25.8 25.5 2.1 60 55 25.9 26.5 0 - 5 29.0 29.1 65 70 Dominguez 29.8 28.8 17.1 75 70 30.1 29.2 ... ... 31.7 35.5 ... 75 80 32.3 35.7 ... Torrance 15.0 1.9 0 - 5 11.2 22.1 +25 8.9 20 23.2 25.0 ... +35 +40 23.9 26.4 ... ... ... Rosecrans 36.7 43.2 +so 75 37.2 29.8 ... ... ... 38.6 40.6 41.0 49.1 33.4 75 80 42.1 59.1 Montebello 18.9 1.0 10 15 21.3 1.7 ... +l5 10 23.5 3.9 14.9 +45 +40 26.2 8.4 ... 26.8 7.9 *.. +45 +40 Whittier 17.4 0.8 - 5 10 19.3 3.2 11.6 - 5 - 10 21.1 3.5 ... 23.1 3.8 ... +35 30 Coyote 20.0 1.9 24.5 ... 8.7 60 26.1 14.1 14.9 28.8 27.2 30.7 32.8 ... ... 32.2 ... 36.2 +75 70
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Sulfuric Acid Absorption and Iodine Values of Various Petroleum Products and Cracked Distillates Obtained Therefrom-Correction I n our article under this title, THIS J o , ~ A L 17, , 1259 (1925), t h e last line in Table I1 should read (a) . . Cracked distillate. ( 6 ) Charging oil.” I n the graph entitled “Relation between Iodine Numbers and Weight of Samples of Cracked Distillate and Corresponding Charging Stock,” the designations of Curves 1 and 2 should be reversed: JACQUE C. MORRELL GUSTAVECLOPF
67
The Haglund Process for the Electrothermic Production of Pure Aluminium Oxide’ By Ture Robert Haglund RUNEBERGSOATAN 8, STOCKHOLM, SWEDBN
I .
X’ T H E Haglund process the impurities of the bauxite
e., iron oxide, silica, etc.,-are reduced with carbon in an electric furnace, which is run continuously. The most important new feature is that the resulting aluminium oxide slag contains a certain amount, about 15 to 25 per cent, of a sulfide, preferably aluminium sulfide, which at the temperature prevailing in the furnace dissolves the aluminium oxide. Through this agent the melting temperature of the slag is considerably lowered (the melting point of aluminium sulfide is about llOOo C., of aluminium oxide about 2200’ (2,). The sulfide-oxide slag is very fluid and therefore easy to tap, and separates easily and completely from the resulting alloy. As an additional advantage the aluminium oxide in the sulfide-oxide slag crystallizes when the slag is solidifying. The sulfide may be separated from the oxide crystals by a very simple operation. The aluminium sulfide may be manufactured by a separate operation and then charged together with the other raw materials, but it has proved advantageous to arrange the process so that the aluminium sulfide is formed in the process itself. Bauxite, carbon (coke or charcoal), and pyrotite (magnetic pyrite), or some other sulfide of a heavy metal are treated in an electric furnace. Aluminium sulfide is formed according to the following equation: -1.
+ 3C + 3 FeS = Al& + 3CO + 3Fe
It is assumed that aluminium is first reduced as metal and immediately reacts with ferrous sulfide forming aluminium sulfide. Twenty per cent of alumini.um sulfide in the sulfideoxide slag is sufficient for obtaining a pure aluminium oxide. I n addition to the carbon needed for the reduction of the impurities of the bauxite, therefore, enough carbon has to be added for the foregoing reaction, which results in the formation of about 20 per cent aluminium sulfide. Further, enough pyrotite, or other sulfide of a heavy metal, has to be added to transform the reduced aluminium into aluminium sulfide. If the bauxite is high in iron it has proved advantageous to treat it with hydrogen sulfide obtained by the decomposition of the aluminium sulfide-oxide slag. This treatment may be combined with a calcining of the bauxite. Through this sulfurizing of the bauxite the consumption of pyrotite in most cases will be reduced to one-third and the consumption of electric power will be reduced to about 75 per cent. Besides the aluminium sullide oxide slag a rather considerable quantity of pig iron containing all the silicon of the raw material is obtained. This iron separates readily a t the tapping of the furnace from the sulfide-oxide slag. The iron is very low in sulfur because of the high temperature in the furnace and of the greater affinity of the aluminium to sulfur. By regulating the rapidity of the cooling of the slag, crystals of different sizes can be obtained, which is important when manufacturing alumina for abrasive purposes. After cooling, the slag is crushed and treated with water in a suitable apparatus operating continuously. Hereby the slag is decomposed according to the equation: ALSa
+ 6 HpO = 2Al(OH)s + 3HrS
The hydrogen sulfide is carried off and used for sulfurizing the bauxite or for the manufacture of sulfur in a Claus fur1
Received July 29, 1925.
INDUSTRIAL AND ENGINEERING CHEMISTRY
68
nace. A mixture of crystallized oxide and aluminium hydroxide mechanically mixed with smaller quantities of iron sulfide, titanium sulfide, etc., remains. This mixture ie treated on classifiers, concentrating tables, and other dressing apparatus. The products are pure, crystallized aluminium oxide, aluminium hydroxide mixed with a small percentage of crystalliwd aluminium oxide, and finally impurities consisting mainly of undecomposed sulfides and iron pebbles. The crystallized aluminium oxide is washed with warm sulfuric acid and finally dried. The aluminium hydroxide can be calcined and circulated in this process or used for the manufacture of pure alumina or aluminium salts, or for cement fondu. Experiments on a noncommercial scale have proved that anhydrous aluminium chloride can be produced direct from the aluminium sulfide in the sulfide-oxide slag without any difiiculty in the separation and washing of the crystallized aluminium oxide. This possibility is important commercially, as an inexpensive anhydrous aluminium chloride is of great interest as a means of cracking crude oil. Analysis of Product The analysis of the aluminium oxide made by the process is even better than that of the oxide obtained in the usual chemical process and used for the electrolysis in one of the biggest aluminium works in Europe. It has also been found that this crystallized aluminium oxide, when electrolyzed in the usual way, gives pure and sound metal, without any difficulty during treatment in the electrolytic bath. Aluminium oxide produced according to this method in Sweden and in Germany gives a product having the following impurities: SiOt Ti02
S
Fer01
Per cent Trace to 0.02 0.18 to0.26 0.16 to0.20 Trace to 0 . 1 2
It must be taken into consideration that the smelting and even more the after-treatment during the experiments in Sweden and in Germany have been rather provisional. Thorough investigation has also proved that the titanium oxide and sulfur can be almost entirely removed by washing with hot acid, these impurities probably existing as titanium sulfides. Cost of Production The building costs for a plant using this process are much lower than those for a plant using any of the chemical processes. One of the big European aluminium companies has estimated that for a new chemical alumina plant the building costs are about 5 million dollars, whereas for a new plant, which they have decided to build for the Haglund process, the maximum estimate is 1.25 million dollars, both figures being calculated on an output of about 25,000 tons of aluminium oxide per annum. This difference in the building costs means a saving of at least 15 dollars per ton aluminium oxide for interest and amortization. Another important advantage of this process over the Bayer or other chemical processes is that even bauxites so high in iron and in silica that they could not be used in the chemical processes will give a pure aluminium oxide when treated according to the Haglund method. Moreover, even the economy of the process is hardly dependent upon the quality of the bauxite, because the iron oxide and silica present are reduced and transformed into easily salable high-silicon pig iron. The cost of manufacture given in the accompanying table is based upon results obtained during experiments carried on in Lautawerk in Germany between May and November,
Vol. 18, No. 1
1924, and upon prices supposed to be average prices for a German aluminium plant with an output of 25,000 tons of A1203 per annum. As under some conditions it is economy to sulfurize the bauxite before charging, the difference in this respect depending mainly upon the content of iron oxide and on the prices of pyrotite and power, the costs are given for both procedures. The costs for the Bayer process based upon the same average prices for power and raw materials are also given for comparison. Production Costs Haglund Method BAUXITE SULFURIZED BAUXITENOT SULFURIZED Marks/ Marks/ 1000 kg. 1000 kg. Bauxite, 2000 kg. at 26 marks 52 2000 kg. at 26 marks 52 Pyrotite, 333 kg. at 30 marks 1000 kg. at 30 marks 30 10 Koke and kokeduff (50 : 5 0 ) , 400 kg. at 20 marks 8 400 kg. at 20 marks 8 Electrodes, 35 kg. at 350 marks 40 kg. at 350 marks 12.25 14 Other materials 8 10 Power, 4500 kw.-hrs. at 0.8 pfennig 36 6000 kw.-hrs. at 0.8 pfennig 48 Labor 16 16 ReDairs 8 GeherG costs IO IO Amortization and interest 10 per cent 5,000,000 marks 2o on 20 25,000 tons 180.25 216 Less value of by-products 30 53 Net costs for 1000 kg. AlzOa excluding li150.25 163 cense Bayer Method Marks/ 1000 kg. Bauxite, 2000 kg. at 26 marks 52 ’ 34 Coal. 2000 kg. at 17 marks Soda and lime 25 Repairs and supply includin filter cloth 35 Power, 300 kw.-hrs. at 0.8 pfennig 2.40 Labor 35 General costs 10 , cent on 20,000,000 marks 80 Amortization and interest 10 per __.
-
-
-
-
25.000 tons ,
Net costs for 1000 kg. AlzOa excluding license
273.40
The Haglund method is well protected by patents and patent applications in all countries of any importance in this connection.
Nonflammable Liquids for Cryostats Several very serious laboratory accidents have resulted from the use of flammable liquids t o form the bath of a cryostat. Because of this the Bureau of Standards has endeavored t o find liquids that will not burn, t h a t have very low freezing points, and that are otherwise suitable for use as cryostat liquids. The materials tried were halogen derivatives of methane, ethane, and ethylene, and mixtures of these substances containing from two t o five components. The freezing points, and in some cases the viscosities of such liquids were determined. Attention has also been given to their corrosiveness. The following liquids are recommended for use t o the limits indicated: Temperature limit LIQUID Carbon tetrachloride Chloroform Carbon tetrachloride Chloroform Ethyl bromide Chloroform Ethyl bromide Trans-dichloroethylene Trichloroethylene Chloroform Methylene chloride Ethyl bromide Trans-dichloroethylee Trichloroethylene
Per cent
... ...
49 4
50:6)
...
;:::} 19.7
c. -. 23
-_
63 --,SI
-118 -139
21.6
!!!!] 10.4 16.4 18. I 12.7
19.9
-146or -150
About
- 150
