US952914A - Ore-briqueting. - Google Patents

Description

posure to the gases of the furnace to which I'o itawtng. Application filed August 14, 1908. Serial No. 448,544.

I To all whom it may concern: t

' slag whichhas osghiti.

Patent No. 78fifpi'3'is best suited STATES PATENT OFFICE,

Be it known that I, Wxmuulu Lrssiso, a

' rsu ject of the German Emperor, residing at Troisdorf. ltheinland, Germany, have inventedeertain new and useful 1m n'ovements inGre-Briquetiug, of which the ollowing is a s dedication,

' he UlJjtttt of th s invention Is to produce to pieces or ermrihle in transport to or exthe ore is to be smelted.

According tothepresent invention the pulverized charge, oredustror fine-' rained ore is eaked wit the presence of u 51th 'or without admixtures. 'l'ests hmeshown, that slag treated ,as set forthin tluis 'ieeifieation of my U. S. for t to purpose indimlted. j- Ilowever, the pulverization of the slug may also he performed by the direct action of a stream-of air charged-with pulverized admixtures,for'exzun 'ile lune.

.For the manufacture of ore-liu-iquets for smeltin r purposes :it has heeu' proposed mix pu verized iron oreund the like with round blast-furnace slag, alumina and hue. The term cement cannot be accuretely applied tovthe niass'forlued by these i admixtun-s. though the'said mass unghtghtarded' as the 'rau material of cement,

without the binding power imparted by burning. In practice it has been found that briquets made of the mixture deserilmd, or of similar mixtures, *do not even possess soilicient durability to enable them to conveyed to the v ast furnace or even if they can be placed whole in the h eruted in the upper part of the furnace cause the cakes to,crumble to dust, which is blown .out of the furnace by the blast before it reaches the "smelting zone, so that the iron this processthe binding Bpcctflcetton of Letters Patent. Patented hlarzz, 19

briquets 'of ore a nd slagewhich will not fall 1 ,the-aid of blasturna e ously been treated in of -bind1n agent lcqltlletl renders not only last furuaee the l hot air-blast and the vapors and gases gen- WILHELM LE$SING OF TROISDORFJGERMANY. 4

OBE-BRIQU ETING.

; state to the action of high pressure steam, it hasheen found that the minute cavities in the binding agent contain water which is evaporated when the briquets enter the u perzone of the smelting furnace, and t e steam thus generated causes the hriquets to crumble before they reach the smelting zone of the furnaoe.

'.,In my present invention the binding agent is perfeetlydrfy, and produces highly porous brl uetspwhic 1 ar ver ermeable to gases, sot atthe reduction of tlie ore is materiallv assisted by the action ofcarbon monoxh. The improved briquets do not require it high degree of compression, such as would reduce their porosity, and the smaller proportion the :ananu ucture of the briquets', but also obviates the risk of loss of ore due to the em- I bedding of ore-particles in a vitreous muss ;by which access of the re'dmring guses is prevented.

The pulverized sla ris, according to the present invention, fine y ground, either alone or with admixtures adapted to increase its binding power in. ease the said binding power is not naturally of :1 hi h order or has not. previously been increase by means of admixtures introdtu-cd durin r the-pulveriz- 'iug process. The meuly pow or obtained by with the ore, iron residue, ore-dust or the like and the mixture is luoldedunder pressure in the usual uunner. The cakw thus produeed become in -a con iparatively short time sullieientlyhard to hrs-transported and subjected to the smelting process. This is; due to the fact that durin r the pulverization of molten blast furnaoe slag the greut'er part of the suljur eontainedtherein is' separated in counteracts the inding power of the cement. If admixtures are introduced during the pulverizing prmess the pulverization is accompaiuied by a process anulo ous to that which takes place in a. cement urnace, and this process is considerably assisted by the burning of the sulfur und sulfui-eted hydrogen, so that the product is at least equiviilent, in bindin and cement the important advantages'that; it led uees the cos of nanufacturm the ore t the smeltingprooess, more economical, and

the grinding process is intimately mixed.

cakes, thetsmeller quentitiestliereo m suf the form of stflfur dioxid or sulfureted hydroge-n, or bothLso that the sulfur no'longer power, to lorthind cement of {good quality. It has, however, over Portficient, that the cakes produced are more porous or ermeable to the furnace ses, and that e chemical composition 0 the binding agent is better adapted for the purpose in view. a

It has been found that the binding. agent is considerably improved by adding a suitable quantity of alkaline salt, which may either be ground up with the slag or added after the grinding. 13% means of such addition' the setting of t e briquets is accelerated, and risk of cracking by frost is reduced, more articularly if the salt used is "chlorid of ca cium'. On the other hand the presence of salts of the alkaline metals or earth metals prevents too rapid drying of the briquets, es ecially in summer, and ,enables aftificlal heat to be applied without risk of drying the mass before the bri nets have set. Chlorid of calcium and ch orid of potassium also have the advantage that they assist in the elimination bf sulfur, phosphorus, copper, zinc, arsenic and the like during the smelting with the silica in the s ag and the iron oxid in the, ore they cause, moreover, a fusing together of the briquet-particles and thus prevent sudden disintegration of the briuets by the heat of the smelting zone.

nether advantage of the alkaline salts is that thev render the slag basic and easily liquefiable, so that the proportion oflime can increased without risk of producing a tough, viscous mass dangerous to the furnace. The alkalies also assist in the extraction of the manganese with the iron, which is an important advanta e.

A very important a vantage of using,

for the manufacture of the ore briquets, slag which has been granulated in the presence of air, lies in the fact that the air-treatment of the slag renders it possible to use slags which are unsuitable for the briqueting rocesses hitherto used, by reason of the Purge roportion of manganese therein. Tests have been made with spiegel-eisen slag conas much as 10% of manganese taining nearly free from phosphorus, with a high I rocess; by coaction v proportion of lime,.and it was found that by granulation this slag is converted e (1 into a ginding agent particularly suitable for brique'ting, by reason of the large proportion of manganese. The manganese not only enriches t is iron but also'assists in eliminating sulfur. This latter function is important if the binding agent is used in conjunction with spent pyrites nearly free from phosphorus but containing a considerable proportion of sulfur. If the presence of manganese inthe iron is not desired, a considerable proportion of man nese in the binding a ent is still usefu for renderin the slag asic and easily liquefiable aim for binding the sulfurpresent.

lVhat I claim as my invention and desire to secure by Letters Patent of the United States is y i 1. In ore briqueting the process ,ofvproducing slag cement which consists in granulating blast furnace slag in the presence of air, grinding the product in the resence of materials adapted to strengtgen the u-mentitious properties mixing the product with ore and forming same into briquets.

2. In orebriqueting, the process of pro 3. In ore briqueting the process of producing slag cement which consists in granulating blast furnace slag in the presence of air, 'rindin the roduct in the presence of alkaline sa ts .a apted to strengthen the cementitious properties mixing the product with ore andforming same into briquets.

In witness whereof I have signed thisspecificationin the presence of two witnesses.

WILHELM LESSING. \Vitnesses: r

LOUIS VANDORN,

H. Srnnznn.