HYDROMETALLURGICAL PROCESS

Zinc oxide is a fluffy white powder used for a wide range of technical applications as rubber and ceramics, in foods, paints, and in chemical applications. Current global production is more than 1 million tonnes per year.

Traditional processes for the production of zinc oxide are the French (or indirect) and American (or direct) process. The French process requires pure or secondary zinc metal, and the American process uses oxidised materials as raw material. The complexity of the process is linked to the purity required and the purity of the raw material. ZnO is finally obtained by burning zinc fumes with air. A third process is the wet process. Zinc salts such as zinc carbonate or zinc hydroxide are calcined (heated) to obtain zinc oxide. Suitable feed includes secondary materials such as zinc sulphate solution, or oxidised ore, which may be dissolved in an appropriate leaching liquor.

ZincOx utilises the wet process on raw materials such as EAFD (Electric Arc Furnace Dust) or oxidised ore. The zinc contained in the feed material is leached in a basic chemical solution. The zinc is then precipitated as a basic zinc carbonate during the stripping of the chemicals. This basic zinc carbonate is then transformed into zinc oxide by calcination.

UNIQUE PRODUCT PERFORMANCE

The wet process allows ZincOx to obtain unique performance and characteristics for its zinc oxide. The precipitation and calcination conditions produce a high purity zinc oxide. A micro agglomerate product can be obtained, which has improved flowability characteristics and reduced dust levels when compared with standard zinc oxide products.

ZincOx have also developed a product especially suited to the needs of the rubber industry. The product has been tested in collaboration with well established laboratories, and is equivalent to the Red Seal grade. Impurity levels are comparable to the higher White Seal grade and the shape of particles is nodular.

Above: Electron Microscopy images. Left - standard micro agglomerate product. Right - Nodular shape rubber product.

STRONG R&D SUPPORT

A strong professional team provides support for product applications including ceramics, animal feed and chemicals. All products are first tested in our laboratory and produced in our pilot plant, before final testing in independent accredited laboratories.

Following initial contact by a customer, customer requirements are analysed and a solution proposed. This focusses on achieving cost effectiveness for the customer by identifying and providing the right product for the application at the right quality level.

Our marketing department would be pleased to assist you. Please contact marketing@zincox.com with your requirements for any specific application, or for product data on on our general products please click on either of Standard ZnO or Rubber grade ZnO.