Almonty Industries Inc.

Flotation

The sulphide flotation circuit consists of a rougher flotation stage followed by two cleaner flotation stages, designed for removal of sulphide. Initially, ground pulp will be conditioned in a dedicated tank for about seven minutes, where Aero 3473 collector and MIBC frother will be introduced to enhance sulphide mineral attachment to bubbles. Subsequently, the pulp will be pumped to a bank of three 30 m³ flotation cells, configured sequentially to improve sulphide recovery. Rougher concentrate from these cells will then be pumped to the first cleaner flotation cells (four OK1.5 cells), where additional purification occurs. The concentrate from the first cleaner will then progress to the second cleaner flotation stage, utilizing four smaller OK0.5 flotation cells. Cleaner concentrate, after this two-stage cleaning process, will be directed to the final tailings pump box. Inline samplers will allow continuous sampling for analytical quality control.

The scheelite rougher flotation circuit will receive conditioned pulp following the sulphide flotation stage. The circuit consists of two sequential conditioning tanks, each designed to provide mixing and contact time of approximately 11 minutes. The first conditioning tank adjusts pulp pH and introduces critical flotation reagents such as sodium carbonate and sodium silicate, while the second tank dilutes pulp density to around 35% solids. Following conditioning, pulp will be transferred to a scheelite rougher flotation bank consisting of four 30 m³ flotation cells. Reagents, specifically TOFA as a primary collector, will be added to promote efficient scheelite mineral attachment. Rougher concentrate will proceed to the cleaner flotation circuit, while rougher tailings will be directed to scavenger flotation cells for further recovery.

Tailings from the scheelite rougher flotation circuit will be pumped to the scavenger circuit, consisting of two separate banks of four 30 m³ flotation cells each. Before entering the scavenger flotation cells, the pulp will undergo additional conditioning where reagents, primarily TOFA, will be reintroduced to improve flotation effectiveness. The scavenger flotation stage is designed to capture scheelite particles that were not recovered in the initial rougher stage, to enhance overall tungsten recovery. Scavenger tailings, after passing through an inline sampler for continuous monitoring, will be considered final tailings and pumped to the tailings thickener for dewatering and disposal. The scavenger circuit is very important in minimizing tungsten losses.

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The scheelite cleaning circuit provides a multi-stage flotation process for the final upgrading of scheelite concentrates derived from rougher and scavenger flotation stages. This circuit comprises four sequential cleaning stages. Cleaner stage 1 consists of three 5 m³ flotation cells, while cleaner stage 2 utilizes two OK1.5 flotation cells. The final two cleaning stages (cleaner stages 3 and 4) will each utilize two OK0.5 flotation cells arranged sequentially. Throughout the cleaner stages, sodium silicate will be continually dosed as a depressant to prevent unwanted mineral flotation, to produce high purity scheelite concentrate. Temperature-controlled conditions (approximately 30–32.5°C) will be maintained using a heated water system to assist flotation performance. Concentration from the final cleaner stage, after upgrading, is directed towards concentrate thickening and filtration processes, in order to achieve the required market specifications of approximately 65% WO 3.