I/EC Reports THE EDITORS ANALYZE A N D INTERPRET THE CHEMICAL WORLD THIS MONTH

Titanium a la Goldenberg

Much yet must be de­termined, but serious investi­gations of this 3-year-old proposal have been started

W I D E S P R E A D INTEREST wasaroused by our earlier report [IND. ENG. CHEM. 46, No. 10, 13 A (1954) ] on a titanium electroplating process pro­posed by Leo Goldenberg. The editors have followed with con­siderable interest the attempts of Goldenberg to have his proposal seriously investigated by some organ­ization—government or private in­dustry—which could furnish ade­quate resources and facilities. Suffi­cient progress has now been made to warrant, in our opinion, a status report to I /EC's readers.

Purpose of the proposed process, described 3 years ago, was electro­lytic reduction of titanium to form a continuous, adherent, nonporous de­posit of massive titanium, as elec­troplate on steel. The three significant features of the proposal were: a fused bath of anhydrous magnesium chloride, operating above the alpha-beta transition of tita­nium, at around 900° C. ; a soluble anode, which could be made either of Kroll-grade sponge ma­terial or of titanium scrap; and comparatively low current densities. While the earlier report stressed the special suitability of titanium plate for application in the marine equip­ment field and in chemical industry, Goldenberg stated his belief at that time that the electroplating tech­nique could be extended to the elec-troforming of commercial titanium sheet.

I /EC published all the very lim­ited process information available at the time—as indications were that patent coverage would be basic— in order to stimulate possible engi­neering development and improve­

ment. The great interest shown by inquiries as a result of the report was clouded by industry and government reluctance to believe that Golden-berg's laboratory results actually produced a coherent and continuous formation, or that magnesium chlo­ride was a unique electrolyte solvent for transferring titanium from sol­uble-anode to massive form, as deposit on the cathode.

The Materials Advisory Board of the National Academy of Sciences recommended that the Bureau of Mines verify the possibility of achiev­ing massive titanium electroplate. The bureau has not yet reported the results of its efforts. The Na­tional Bureau of Standards, how­ever, has reported recently on ti­tanium electroplating in which they used the magnesium chloride sys­tem. NBS has certified that a stable electroplating equilibrium can be established with this system and that a continuous, coherent, and adherent titanium coating can be deposited over the entire surface of a large iron cathode. According to NBS in a private communication to Goldenberg, titanium salts were added to the bath only by electro­lytic oxidation of the soluble tita­nium anode (in accordance with a technique specified by Goldenberg) and cathode current densities were maintained below 3 amperes per sq. dm. (28 amperes per square foot).

Currently, the Engineer Research and Development Laboratory, Fort Belvoir, Va., is investigating the process. Recently, Goldenberg re­ceived confirmation from a major titanium producer that the process "appears workable from a technical viewpoint."

Alternative electrolytic processes have so far failed to be commercially feasible. Goldenberg believes that his original description, "electro­plating" has been interpreted too narrowly. He thinks that it may be possible to convert sponge, oxygen-contaminated scrap, or even carbon-reduced rutile, directly into ductile titanium sheet by his process,

and that, within the limitations of electrolytic codeposition of metals, alloying elements should be includ­able in the massive cathode product.

It is certainly important that the titanium industry develop a non-military tonnage market for titanium as quickly as possible. This can per­haps be done on the basis of reason­ably predictable applications for titanium electroplate. These ap­plications might in turn make pos­sible the development of a sound nonsubsidized electrolytic process for extractive metallurgy of the metal. Commercialization of a steady-state electroplating process, operating under conditions of stable equi­librium, would inherently provide much of the information required for evaluation of the problem of economical conversion of sponge into sheet and other usable forms. It seems to be in the realm of pos­sibility that a plating equilibrium can be maintained where, starting with soluble anodes of titanium-oxygen—such as could be made from carbon-reduced rutile—an elec-trolytically deposited titanium cath­ode, in massive form, can be simul­taneously deoxygenated, electro-lytically, to meet rigorous purity and ductility requirements. W.H.S.

Distilling Titanium and Beryllium

Pure t i tanium and bery l l ium now produced by processes similar to that deve loped by Fulmer for pure aluminum

OEVERAL YEARS AGO a catalytic process for purifying aluminum was developed in England at die Fulmer Research Institute. Now somewhat similar processes have been de-

VOL. 49, NO. 12 · DECEMBER 1957 2 7 A

IEC REPORTS

veloped for t i tanium and beryllium. Othe r processes of this type might eventually be used for other metals, such as zirconium.

In the a luminum process—which is most useful for recovering pure metal from scrap, but which might also be applied to p r imary extrac­t ion—aluminum trichloride is passed over impure a luminum. T h e follow­ing equil ibr ium reaction is set u p :

2A1 + A1C13 : 3A1C1

T h e gaseous a luminum mono-chloride is d rawn off from the im­purities, and then reverts to a lumi­n u m trichloride and purified a lumi­num. T h e trichloride is recycled.

This process has been operated a t Fulmer Research Inst i tute on a small pilot-plant scale, and is being tried in a large-scale pilot uni t in C a n a d a . T h e small-scale p lant consists of a tube about 15 feet long and 6 inches in diameter . Impure scrap is placed in refractory boats at one end of the furnace, and heated. Vaporized a luminum trichloride is passed over it. Fur ther along, in a cooler por­

tion of the tube, a luminum condenses out on graphi te containers. T h e condensed metal is very pure alumi­num.

Some research has also been done using fluorides and bromides, and a subhalide process was also investi­gated in Germany dur ing World W a r II—chiefly for scrap recovery. In the U. S., the Bureau of Mines has worked for several years on an electric furnace method for convert­ing r aw a luminum silicate directly into aluminum-silicon alloys. Re­cently they have looked at the sub­halide process as a way of gett ing pure a luminum from the alloy. Corrosion and other difficulties of working a t high tempera ture will have to be overcome, and it is too soon to say whether the process will be economical. Alcoa is also in­terested in the subhalide process, but adds "h igh initial capital invest­m e n t " to the other problems men­tioned above.

In the t i tanium process, t i tanium tetrachloride is passed over t i tanium alloy and a mixture of lower chlorides

New boron-containing cast carbon steel is made here by Harrison's acid open-hearth process

Dark section shows depth of hardness in sprocket made of Boralloy

is formed. Like a luminum mono-chloride, they revert to^ metal and the higher chloride.

This process can be used for re­moving t i tanium from ferrotita-n ium—obta ined from ilmenite. T o ­day, most t i tanium comes from rutile ( T i 0 2 ) . I lmeni te is more plentiful and would be a valuable t i tanium ore if t i tanium could be extracted from it economically.

T h e process for purifying beryllium is less similar to the a luminum proc­ess. Sodium chloride, ra ther than beryllium chloride, reacts with the metal .

Be + 2NaCl 5 = 6 BeCl2 + 2Na

This process makes it possible to dis­till pu re beryllium from an impure material . T h e beryllium and so­dium chloride react and the reaction products are distilled off, leaving impurities behind. O n condensa­tion of the distillate, the reverse re­action takes place, leaving pu re beryllium and salt, which can be easily separated from each other.

A .S .H.

Versatile Boron Rags to riches element

literally comes down to earth—via new boron steel

TIGH-FLYING BORON, glamor boy among jet and rocket fuels, has come back to earth for a new use. Although a specialized application, its role in lengthening the life of crawler tractor sprockets on earth-moving equipment is another ex­ample of boron's spectacular versa­tility. Boron didn't get into this earthy work voluntarily. It took Caterpillar Tractor and Harrison Steel Castings a couple of years to convince the element that it has a place with the mundane.

The 2-year interval was needed to develop a commercially successful acid-hearth process for boron con­taining cast carbon steel. Until the joint program was started in 1955, boron was added to steel almost en­tirely via the basic electric furnace process.

Boron is wanted in steel because, in minute amounts, it improves

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2 8 A INDUSTRIAL AND ENGINEERING CHEMISTRY