HENRY A. ALLEN

HENRY A. ALLEN, in United States patent No. 762,870, Mar. 16, 1903, described a complicated apparatus for treating ores with oil and other chemicals under super-atmospheric pressure.

JACOB DAVID WOLF, in United States patent No. 787,814, May 22, 1903, duplicated British patent No. 4,793, May 22, 1903.

JACOB DAVID WOLF, in British patent No. 4,793, May 22, 1903, described a method of applying the principles of oil flotation. He used sulpho-chlorinated oil, with violent agitation in a mixer like Fig. 2, and aimed to secure a high degree of mineral extraction with a low grade of concentrate in the first step, and by washing the concentrate with hot water in a suitable vessel to increase the grade of concentrate in the second step ; as a third step in his process, air or steam was blown into the refuse, which raised to the surface globules of lost oil, with some sulphides adhering thereto, thus increasing the extraction.

COSMO KENDALL, in United States patent No. 771,075, July 21, 1903, described a process of separating graphite from gangue by means of oil.

GOYDER & LAUGHTON, in British patent No. 16,839, JmY 3 Z > 1903, described a process of ore concentration that employed the idea of adding the ore to an acid solution. They describe an apparatus for trapping the mineral sulphides as they are brought to the surface. They were the first to disclose the principle governing Potter's and Delprat's acid-flotation processes, namely, that the action of the acid on the ore generated gas-bubbles to which the sulphide particles attached themselves and were floated to the surface. One of the difficulties of the acid-flotation process was that the bubbles broke on reaching the surface, and the mineral particles sank again, that is, the surface tension was not active enough to hold them up. This invention not only seeks to obviate this bad feature of the acid-flotation process, but in a measure takes advantage of it. This machine has horizontal sections decreasing in area upward.

GOYDER & LAUGHTON, in United States patents No. 763,749 and 784,999, Aug. 5, 1903, described an improved form of apparatus and process for the application of the acid-flotation process of Potter, being a duplicate of British patent No. 16,839, July 31, 1903.

CATTERMOLE, SULMAN & PICARD, in British patent No. 17,109, Aug. 6, 1903, described a process of concentration that consisted (1) in mixing the freely flowing pulp with a soap solution and agitating ; (2) adding a small portion of acid to liberate the fatty acid from the soap, whereby the sulphides collected in granules, as disclosed previously by Cattermole, and were removed from the pulp by an upcast current of water ; and (3) generating a gas in the pulp to remove the granules by flotation. After the concentrate was removed it was treated with an alkali, which dissolved the oil of the granules, converting it into a soluble soap, which was immediately available for use again.

MORITZ F. R. GLOGNER, in United States patent No. 736,381, Aug. 18, 1903, described a process for the recovery of graphite, by means of an oil and froth process.

JACOB DAVID WOLF, in New South Wales patent No. 13,571, Aug. 19, 1903, duplicated his British patent No. 4,793 of May 22, 1903.

VAN METER & Boss, in United States patent No. 762,774, Aug. 19, 1903, described an apparatus for the application of the oil-buoyancy process.

ALFRED SCHWARZ, in United States patent No. 766,289, Aug. 19, 1903, described a process for separating sulphides from gangue by the use of oil and saline solutions or other liquids differing in specific gravity. His apparatus is different from any previously described, and he gives a theory for his process which it is difficult to accept.

ARTHUR EDWARD CATTERMOLE, in British patent No. 18,589, Aug. 28, 1903, secured a revision and amplification of his previous patents, and described the formation of granules. He describes an improved form of apparatus. This process failed of practical application.

HOMER L. ORR, in United States patent No. 758, 464, Sept. i, 1903, described an apparatus for separating metallic particles in an ore by means of oil and other chemicals.

GUILLAUME DANIEL DELPRAT, in British patent No. 19,783, Sept. 14, 1903, described a flotation process wherein the bisulphate of an alkali metal is used.

SULMAN & PICARD, in British patent No. 20,419, Sept. 22, 1903, described a process of oil-concentration in which they introduced bubbles of air or other gas, and also oil in the form of a spray, into the freely flowing acidulated pulp. This invention follows some of their previous patents in its main lines, but is novel in the methods of introducing the oil and air into the slightly oiled pulp.

SULMAN & PICARD, in New South Wales patent No. 13,632, Sept. 24, 1903, described a process consisting in the recovery of metallic particles in an ore by floating them to the surface with bubbles and films of air after oiling them with a small amount of oil in an acid circuit.

ARTHUR EDWARD CATTERMOLE, in United States patent No. 763,260, Sept. 28, 1903, duplicated British patent No. 26,295, Nov. 28, 1902.

ARTHUR EDWARD CATTERMOLE, in United States patent No. 777,273, Sept. 28, 1903, duplicated British patent No. 18,589, Aug. 28, 1903.

ARTHUR EDWARD CATTERMOLE, in United States patent No. 763,259, Sept. 29, 1903, duplicated British patent No. 26,296, Nov. 2, 1902.

SULMAN & PICARD, in United States patent No. 793,808, Oct. 5, 1903, duplicated British patent No. 20,419, Sept. 22, 1903. ALICE H. SCHWARZ, in United States patent No. 771,277, Nov. 6, 1903, described a process of ore concentration in which she made use of an oil or grease that is solid at ordinary temperatures.

ISRAEL F. GOOD, in United States patent No. 745,960, Dec. i, 1903, described an oil-flotation method of recovering graphite from rock.

GUILLAUME DANIEL DELPRAT, in British patent No. 27,132, Dec. n, 1903, described the use of a solution of common salt and sulphuric acid to be used in the acid-flotation processes previously disclosed by him.

ALEXANDER STANLEY ELMORE, in United States patent No. 865,334, Dec. I:c > I935 duplicated British patent No. 184, Jan. 3, 1903.

EDMUND B. KIRBY, in United States patent No. 809,959, Dec. 14, 1903, described a process of oil-and-gas flotation, in which air was blown into the previously agitated oiled pulp.

CATTERMOLE, SULMAN, & PICARD, in United States patent No. 788,247, Mar. 29, 1904, duplicated British patent No. 17,019, August 6, 1903, in part.

CATTERMOLE, SULMAN, & PICARD, in United States patent No. 777,274, Mar. 29, 1904, duplicated in part British patent No. 17,109.

JAMES D. DARLING, in United States patent No. 763,859, April 28, 1904, described a method of separating carbon from impurities by means of oil.

SULMAN & PICARD, in British patent No. 13,481, June 14, 1904, described a method of slime-deposition by means of soap, which produces coagulation. This is of, limited interest to this discussion.

FRANCIS EDWARD ELMORE, in British patent No. 13,578, June 15, 1904, described a process of flotation wherein he made use of the electrolysis of water to generate gas in a freely flowing pulp. This patent is chiefly of interest in that it marks the departure of this inventor from his old line of oil-buoyancy flotation, emphasized in his former patents, and he thenceforth turns his attention to gas-and-oil flotation.

JACOB DAVID WOLF, in British patent No. 17,407, Aug. 10, 1904, described an apparatus similar to that of Haultain & Stovel.

FRANCIS EDWARD ELMORE, in British patent No. 17,816, Aug. 16, 1904, described a process to be performed in a vacuum or a partial vacuum. He says he uses a small quantity of oil, and also says that " under a vacuum or partial vacuum, air or gases dissolved in the milling water are liberated. These liberated gases may be augmented by the generation of gases in the pulp, or by introduction from an external source." The apparatus is an admirable invention, and the patent discloses a new principle, namely, the use of the vacuum in connection with the flotation.