A New Recycling Process for Tungsten Carbide Soft Scrap That Employs a Mechanochemical Reaction with Sodium Hydroxide

Abstract

WC soft scrap, including Co used as a binder, thermally oxidized at 600 • C, was subjected to grinding with NaOH in a mechanochemical reaction, followed by water leaching to establish an effective recycling process. Na 2 WO 4 was synthesized through a mechanochemical (MC) reaction with oxidized scrap, and Na 2 CO 3 was formed when the mixing ratio of NaOH increased. These as-synthesized compounds were water-soluble. When the weight ratio of soft scrap to NaOH was 1:0.5, 99.2% W was extracted by water leaching, while the extraction yield of Co was limited to 3.57% under the same conditions.

The Dynamics of Tungsten in Soil: An Overview

“…Further means to reduce environmental impacts, saving resources and reduce costs are being studied [112,113]. Among the innovative approaches for efficient recycling of this element, microbial strategies seem to provide interesting results in the case of mining sites [114].…”

Solid–Solid Separation Approach for Preparation of Carbon-Supported Cobalt Carbide Nanoparticle Catalysts for Oxygen Reduction

“…As shown in Figure S1 (Supporting Information), CoC x exhibits two steps of weight loss, wherein about 1.26% weight loss is observed at <420 °C. This is due to the removal of moisture from the surface of the sample . Thereafter, a gradual increase in the weight of about 16.1% is observed at 500 °C and above.…”

“…This is attributed to the direct oxidation of CoC x , which in turn adds weight to the sample. , In contrast, C@CoC x shows an apparent three-step weight change, wherein a sharp weight loss (36.2%) is observed at about 410 °C due to the removal of the surface moisture as well as a carbon nanotube in the form of CO 2 through the oxidation process. , Thereafter, a further change in the weight is observed at 500 °C. This can be attributed to the CoC x oxidation process, and the remaining weight is found to be 50% at 800 °C. In short, the thermogravimetric analysis evidently shows that there is formation of a carbon nanotube on the surface of CoC x during the synthesis process.…”

“…This is due to the removal of moisture from the surface of the sample. 24 Thereafter, a gradual increase in the weight of about 16.1% is observed at 500 °C and above. This is attributed to the direct oxidation of CoC x , which in turn adds weight to the sample.…”

“…This is attributed to the direct oxidation of CoC x , which in turn adds weight to the sample. 24,25 In contrast, C@CoC x shows an apparent three-step weight change, wherein a sharp weight loss (36.2%) is observed at about 410 °C due to the removal of the surface moisture as well as a carbon nanotube in the form of CO 2 through the oxidation process. 24,26 Thereafter, a further change in the weight is observed at 500 °C.…”