Solvent Extraction Application

Garnet is a high-performance filtration media used between solvent extraction and electrowinning, or SXEW. SXEW is a two-part hydrometallurgical process used to produce copper ore. By using garnet as one bed in a multi-media filter, the quality of the cathode plate is improved and related costs are reduced.

  • Lasts for years
  • Stable in a dual-media design
  • More effective particle arrangement within filter bed
  • Provides great support for other high-density media
  • Filters down to 10 microns
  • Reduces abrasion and expansion
  • Naturally chemical resistant
  • Reduces filter overrun
  • Predictable filter service cycles
  • Filters are online longer
  • Less materials used in backwashing

Solvent extraction and electrowinning are used in 20% of copper production around the world. This method allows copper to be extracted:

  • Without removing the material (in situ)
  • From unconventional sources
  • From waste materials
  • With a much lower environmental impact than conventional smelting


African Pegmatite can custom design media (garnet, anthracite, uniformity coefficients) for virtually any application.

  • High hardness
  • High density
  • High specific gravity
  • Filters down to 10-20 microns
  • Chemically resistant

General Information

During WWII, SX-EW was first used as an extraction method for uranium. It has since been used for the processing of nickel, zinc, and cobalt.

During solvent extraction, a weak acid solution called a pregnant liquor is used to dissolve solid material containing the desired metal, usually copper. An organic solvent, or extractant, is then introduced to the pregnant liquor, extracting the copper from the acid, leaving behind almost all of the impurities from the material.

The aqueous phase is returned to its weak acidity, recycled, and used again for the same process while the copper is extracted from the organic phase by introducing a highly acidic aqueous solution. The copper moves into this new aqueous phase and the organic phase is reconstituted and recycled.

The electrolyte flow passes through seven deionized filters. Finely crushed garnet is used in dual media filtration systems with anthracite to filter contaminants down to a few microns in diameter. This filter system reduces organics and solids, ensuring a clean electrolyte flow into the electrowinning process. The garnet is the primary filter bed and also acts as a coalescing media.

A coalescer is made of two tanks, one within the other. The outer tank is pressurized. The inner tank is connected at the bottom, but the top is open.

Electrolyte flows up through the centre of the inner cylinder and down between the inner cylinder and walls of the outer tank. Organics float and exit the system. Anthracite in the cylinder with a grid on top can improve the performance of this system.

After filtration, copper sulphate is reduced to a copper cathode through an electrochemical process called electrowinning. These cathodes are generally purer quality than those produced by smelting.


Choose the packaging and shipping arrangement that best suits your needs, from small packaging to bulk bags or custom sizes made just for you. We can accommodate virtually any size, from one metric ton to thousands.


We maintain competitive pricing in an effort to win and retain your business for as long as you need us. Our goal is to meet the needs of every customer, including those with special requests and demanding production schedules.

A 15-day general turnaround for manufacturing allows us to get your compounds to you as quickly as possible, so you can keep up with the demands of your business. Contact us to get in touch with a distributor in your area if you don’t have time to wait for materials.

We currently ship to 44 countries across the world and we’re happy to ship to yours, too. The dependable and professional logistics channels we have in place make it easy to offer great pricing and service regardless of your location.

African Pegmatite

With 48 years as professionals in mining and manufacturing, we have the insight, network, and experience to offer you the very best in quality, service, and efficiency. We’ve been accredited by the ISO 9001 since 2002 and have most recently met the 2015 standard.

We aim to provide the very best materials available to our customers, and become your one-stop shop for colourants, minerals, compounds, and more. Take a look at our general solvent extraction page to see all the other solvent extraction and supplementary products we have available.

If you’d like to become a distributor of African Pegmatite products, get in touch with us and we’ll customise an arrangement with you.