JOHN cqwux m, or Yommns, NEW YORK.
Max ne an ALLOY or nanom'anemnsnann SILICON.
1,109,640.. 1T0 Drawing.
Specification of Letters Patent. Application filed February 4, 1913. Serial 1%. 748,187.
Patented Sept. 1, 1914.
To all whom it may concern:
Be it known that I, JOHN C."W'ALKER, a citizen of the United States, residing in the city of Yonkers, State of New York, have invented ne'wand useful Improvements in Making an Alloy of F erromanganese and Silicon, of which the following is a specification.
In the finishingoperation of making or refining steel it is customary to add manganese in the commercial form of ferromanganese.'- Part of this addition is taken up in extracting oxygen from the steel and a part of the manganese remains to alloy with the steel and thereby to materially improve its quality for most purposes. It is customary to add with the manganese a small quantity of silicon in the commercial form of ferrosilicon. The silicon has a greater aflinity for oxygen than manganese and the use of a small quantity of silicon relieves a comparatively large quantity of manganese of its function as a deoxidizer and leaves it free to alloy with the steel. Ferro-silicon is more expensive than term-manganese and is so expensive that the cost of these additions is very substantial. This is especially the case where ferro-silicon of high purity is required. It has been found that steel of better quality is obtained with a smaller waste of term-manganese when the ferromanganese is added in a molten condition.
According to this invention, molten ferromanganese is provided alloyed with a small proportion of silicon in the purest form and at a cost materially below that of silicon in the commercial form of ferro-sili cona The process is best carried out in an electric furnace of the Heroult are type. In such a furnace term-manganese is melted and maintained in a molten condition al,--
loyed with a small amount of silicon, being tapped ofl and replenished from time to time as needed by the steel making furnaces. Instead of replenishing the pool with ferro-silicon, however, I replenish andmaintain a slag containing a high percentage of silicon and sufiicient carbon or other reducing agent (as aluminium, calcium, ac.) to reduce the silica and to rovide pure nascent silicon which alloys with the ferromanganese-in the pool. Reducing conditions i are maintained so thatthere is no chance of reoxidationot the silicon,
The jollowingis a specific example, supposing that the steel-making furnaces repounds of the alloy ferro-silico-manganese per hour. The ferro-manganese melting furnace may contain 9,500 pounds of ferromanganese alloyed with500 pounds of silicon. At the 'end of the first hour, onethousand pounds of ferro-silico-manganese are taken out. This leaves 9,000 pounds of an alloy composed approximately as follows :6,840 pounds of manganese, 1,710 pounds of iron, and 450 pounds of silicon. The slag at this time comprises 200 pounds of'lime, 100 pounds of silica, and certain small remaining roportions of coke dust and fluor-spar. e now replenish the ferromanganese by adding 950 pounds of the same.- The. silicon is replenished by adding 100 pounds of sand and 50 pounds of coke dust and 10 pounds of fluorspar to the slag. During the succeeding hour 50 pounds of silicon are reduced from the slag so as to make up the deficiency, and the slag will thereby be reduced to the due proportions above stated as existing at the end of the quire additions of one-thousand (1,000)
first hour. Further withdrawals of the mixture and replenishing thereof are effected in the same Way.
In most. plants the practice will be to require withdrawals of the ferro-silico-manganese at more frequent intervals and in correspondingly smaller quantities than in the above example. In such cases the ferrosilico-manganese will be replenished more fre uently and the quantities necessary for rep enishing the pool will be proportionately diminished. .A certain amount of time is necessary to heat and melt the additions of sand and coke dust and ferro-manganese;
therefore, where frequent withdrawals and.
replenishings are necessary it may be ad- -v1sable to employ two or more furnaces -workingin the manner above described so as to be able to give each furnace alonger rest between additions and withdrawals than would be the case if only one furnace were emplo ed.
What I c aim is- '1.- In the making of' ferro-silico-manga nose the process which consists in melting form-manganese and producing nascent silicon in the presence of the molten fei'ro manganese and causing the silicon as it is produced to combine with the ferro-manganese.
2. In the making oi ferro-silico-mangancse the process which consists in meltin term-manganese and reducing silica to silicon in the resence of the molten ferro-manganese an maintaining non-oxidizing conditions so as to prevent reoxidation of the silicon and to cause it to combine in nascent condition with the ferro-manganese.
3. In the making of ferro-silico-manganesetheiprocess which consists in providing a pool of ferro-silico-manganese withdrawing portions thereof from time to time and replenishing the same by the addition of ferro-manganese to the pool and the addition of silica and a reducing agent to the slag and heating the same to reduce the silica to silicon, and maintainin non-oxidizin conditions: to prevent reoxidation of the silicon and to cause it to combine in nascent condition with the metal of the pool.-
L In-the making of terro-silico-manganese the process which consists in pro iding a pool of ferro-silico-manganese, withdrawing portions thereof from time to time