Chromium-vanadium steels are the latest development in structural alloy steels that have gained an extensive market. Almost all these steels are made in the open-hearth furnace; the chromium and vanadium alloys being added shortly before casting. In their physical properties these steels are much like chrome-nickel steels, but they have a greater contraction of area for a given elastic limit than the latter. The greater part of the chrome-vanadium steels made goes into automobiles. Some manufacturers prefer such steels because of their greater freedom from surface imperfections, notably seams, which steels containing nickel are prone to have if the ingots are at all unsound. These steels are almost always used in the heat-treated condition, but even in automobiles some frames, forgings and shafts are made of the steel in its natural state.
Some chrome-vanadium steel is said to be used in armor plate of medium thickness, which is not face-hardened but has high resistance imparted by heat treatment.
Vanadium is also used to some extent in making bronzes, in medicine and in dyeing.
Substitutes.
—Several substitutes, chiefly titanium and molybdenum, have been claimed to give the properties of vanadium in steel. Both of those metals give to steel some of the properties that are usually associated with vanadium, but neither one takes the place of vanadium entirely.
CHANGES IN PRACTICE
The Primos Chemical Co. (see [later]) has its own patented method for treating roscoelite, the ore found at Newmire, Colorado. This method consists in roasting the ore with salt containing a little pyrite, and is a method that is applicable to some extent to most vanadium ores that do not carry lead. The American Vanadium Co. has a secret process for the treatment of its Peruvian ores. This method has not been published. The treatment of vanadinite, cuprodescloizite and carnotite ores has been studied by the U. S. Bureau of Mines, at Golden, Colorado. Whatever change in practice takes place is likely to be mainly in the concentration of vanadinite and in the treatment of this mineral and cuprodescloizite.
GEOLOGICAL AND GEOGRAPHICAL DISTRIBUTION
Peruvian Deposits.
—The largest deposits of vanadium in the world, and the most important, were until recently controlled by the American Vanadium Co. of Pittsburgh, Pennsylvania, which in 1919 was absorbed by the Vanadium Products Corporation, allied to the Bethlehem Steel Corporation. These deposits are at Minasragra, Peru, 20 miles from Cerro de Pasco. The area lies along the western limit of a broad anticline in Juratrias and Cretaceous rocks. A section shows the series in this locality to be composed of green shales, thin beds of limestone, and red shales. Vanadium is found only in the red shales. The deposit proper appears to be a lens-shaped mass, 28 feet wide and 350 feet long. The ore contains several minerals. The mineral that constitutes the large portion of the deposit is called “quisqueite”; it is a black carbonaceous substance containing sulphur. There is also a lesser quantity of a coke-like material. Neither of these contains vanadium. The vanadium is mostly at the southern end of the ore body, and to a depth of 20 feet is largely in the form of red calcium vanadate, which is brighter colored then the calcium vanadate in Colorado and Utah, and carries as much as 50 per cent. vanadium oxide. It occurs in small pockets and fills the cracks and fissures in a fine shale. Below this shale is the “mother lode,” which is 9 to 30 feet thick, extends along the greater length of the deposit, and carries as high as 10 per cent. vanadium oxide and nearly as much sulphur. On the east and south sides, below the “mother lode,” is a hard blue-black vanadium shale, carrying as much as 13 per cent. vanadium oxide and 4 to 5 per cent. sulphur. Patronite, the main vanadium mineral, is greenish black and contains 19 to 24.8 per cent. vanadium oxide and in places 50 to 55 per cent. of combined sulphur. The patronite originally almost reached the surface and is most abundant in the north half of the lens. The whole ore body is almost completely inclosed by porphyry dikes and contains two or three intrusions. These deposits are controlled by the American Vanadium Co., and its successor, the Vanadium Products Corporation, through a concession from the Peruvian government. They are large, but are by no means inexhaustible, and as they are entirely local they are not likely to be duplicated. No similar deposits are known, either in Peru or in any other part of the world.