Scheelite fines recovery and calcium mineral separation

In China, scheelite-type tungsten deposits are primarily sandstone-type and composite-type (fine-vein disseminated type combined with greisen-skarn type). These deposits are often associated or coexisting with polymetallic minerals such as molybdenum and bismuth. The valuable minerals exhibit fine disseminated grain sizes, typically embedded as impregnations within the ore.

Scheelite generally achieves ideal liberation at particle sizes suitable for flotation, and its flotation performance is superior to that of wolframite. Therefore, the beneficiation process for scheelite predominantly relies on flotation.

The scheelite flotation process is typically divided into three stages: sulfide ore flotation, tungsten roughing, and cleaning. The principle flowsheet for sulfide ore flotation resembles that of conventional sulfide ore processing plants, with variations depending on the sulfide mineral composition. During tungsten roughing, sodium carbonate and sodium silicate are commonly used as regulators, along with fatty acid-based collectors. Some plants also employ chelating collectors. For scheelite rough concentrate cleaning, two primary methods are currently adopted: heated flotation and ambient-temperature flotation.

Case Study of a Specific Mining Area
The deposit in question is a skarn-type scheelite ore with fine-grained dissemination, coexisting with lead-zinc sulfide polymetallic minerals. After primary crushing, the raw ore undergoes two-stage hand sorting to discard waste. Qualified ore is then ground and subjected to sulfide ore flotation to comprehensively recover copper, lead, and zinc. The tailings from sulfide flotation enter the scheelite flotation circuit. During roughing, collectors 731 and 733 are applied, with sodium carbonate and sodium silicate as regulators, following a "one roughing, three scavenging, one cleaning" flowsheet to obtain scheelite rough concentrate. Subsequently, under high pulp density conditions, the rough concentrate undergoes prolonged agitation with sodium silicate, followed by ambient-temperature cleaning via a "one roughing, two scavenging, five cleaning" process, ultimately yielding qualified scheelite concentrate.