The Dow Chemical Company

Other

James E Hillis

William G Green

William E Mercer, Ii

William P Coker

Harvey L King

Barry A Mikucki

Reed S Dickinson

Vladimir Petrovich

Disclosed is a composite material and a method for the manufacture thereof. The disclosed material includes a layer of polymeric material in substantially continuous surface-to-surface contact with a layer of cementitious material. The composite material can be used as both a planar tactile warning and as a subunit in the construction of three dimensional structures. The external surface of the polymeric material can be configured, i.e., textured or smoothed, as needed for a given application.

Composite material and method for the manufacture thereof

A method for producing a high purity magnesium alloy is disclosed in which the alloying components are introduced in the molten state into molten magnesium. In accordance with the process of the invention, a predetermined amount of primary magnesium is heated and melted in a crucible. Predetermined amounts of desired alloying metals are selected and heated to their melting temperature in a separate crucible. The molten alloying metals are then introduced into the molten magnesium to substantially instantaneously alloy with the molten magnesium in a reaction raising the temperature of the melt. Elemental manganese when first alloyed with other alloying metals prior to its addition to the molten magnesium is found to consistently be more effective in reducing the iron impurity level of the melt to a level below 50 ppm. The introduction of a molten alloy of manganese and one or more rare earth metals into the molten magnesium, reduces a settling out of the rare earth metal from the melt and increases the alloying efficiency for the rare earth metal to greater than 80%. The efficiency of the process of the invention is substantially increased, the consumption of time and energy is decreased, and the production of magnesium chloride slag and gaseous HCl is avoided.

Methods for producing high purity magnesium alloys

Hydrogen is essentially removed from molten magnesium by the use of a degassing step, thereby substantially avoiding the formation of zirconium hydride when zirconium and silicon are added to the molten magnesium, after the degassing, in order to precipitate iron contamination in the magnesium as an intermetallic compound comprising Fe, Zr, and Si; the ratio of the three metals in the intermetallic compound can vary over a wide range. By essentially avoiding the formation of slow-settling insoluble ZrH.sub.2, the iron removal is more efficient and the settling of the insolubles is expedited. Also, the Fe and Si are more effectively and consistently precipitated.

Process for purifying magnesium

A process for removing iron contamination from molten magnesium by adding to the molten magnesium a mixture of a boron-containing compound and a flux. The boron-containing compound includes, for example, elemental boron, boric acid, and boron oxide. The flux is a conventional magnesium flux. The flux and boron-containing compound mixture is prepared by any suitable means and then added to the molten magnesium at melt temperatures of from about 650.degree. C. to about 700.degree. C. The iron contamination in the magnesium product can be reduced for example from about 400 ppm to less than about 10 ppm.

Composition for removing iron contamination from magnesium

A process for producing magnesium low in iron contamination including contacting a magnesium melt with a combination of a zirconium material and a silicon material to reduce the iron contamination without introducing detrimetal levels of reagent elements in the product magnesium.

Process for producing high purity magnesium

Method for removing iron contamination from magnesium

Mono- and dibasic alkali metal periodates are prepared by reacting tri-, tetra- and pentabasic alkali metal periodates with a substance having a relative acidity value, pKa, of from 3 to 16 at a temperature of from 0.degree. to 100.degree. C at molar ratios of periodate to moles of acidic substance of 1:1 to 1:1000. The mono- and dibasic alkali metal periodates are useful in oxidizing olefins such as propylene to the corresponding oxide such as propylene oxide.

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Angleton, TX, United States of America

James E Hillis