DOWEX Resins for Separation of Tungsten from Liquid Media

Tungsten - W Tungsten is found naturally in combination with wolframite, scheelite, huebnerite and ferberite. Tungsten ore mines, which are located in South Korea, Portugal, Austria, and Australia, produce more than half of the world's supply. The predominant ionic form of tungsten is W (VI). Its main industrial uses are in the manufacturing of lighting and heating elements. The ionic chemistry of W (VI) is very similar to other Group VIB elements, Mo (VI) and Cr (VI).

Applications

Mining: Ion exchange resins are employed in the commercial mining and refining of tungsten. Both, strong base and weak base anion exchange resins are employed for removal from strongly acidic feed streams. Nevertheless, the weakly basic anion exchanger, DOWEX™ M-43 resin is preferred for its high capacity and cleaner elution characteristics. Elution is usually accomplished using 10% sodium hydroxide.

Wastewater/ Groundwater: In waters with low levels of W (VI), strongly acidic cation exchange resins such as DOWEX G-26 (H) cation exchange resin are employed. Weak acid cation exchange resins such as DOWEX MAC-3 resins often provide high capacity and good multi-valent ion selectivity. However, in more brackish waters, chelating resins may be required. Chelating resins have reactive units dispersed along their polymer matrix, each of which have multiple metal binding sites. Hence, chelating resins are selective for multi-valent cations, over mono-valent cations such as sodium and potassium.

DOWEX Ion Exchange Resins

Product	Description	Type	Matrix	Total Exchange Capacity* eq/l (kgr/ft3)	Available Forms
DOWEX M-43	Corrosion control with DOWEX M-43 ion exchange resin.	Weak Base Anion	Styrene-DVB, Macroporous	1.55	FB (Free Base) form
DOWEX G-26 (H)	Uniform particle size strong acid cation exchange resin for specialty demineralization and catalyst applications.	Strong Acid Cation	Styrene-DVB, Gel	2.0	H+
DOWEX MAC-3	A macroporous weak acid cation exchange resin used for water softening, dealkalization, and demineralization applications.	Weak Acid Cation	Polyacrylic, Macroporous	3.8 (83.0)	H+