How Buffalo Potash Recovers MOP: Crystallization to Compaction

Source: Buffalo Potash Corporation (2026)
Website: https://www.buffalopotash.ca/

Critical Data

Overview

Buffalo Potash Corporation (BPC) is advancing the Disley Project in Saskatchewan, Canada, with a staged development plan that begins with an Initial Production Module (IPM) producing 125,000 t/a of soluble muriate of potash (MOP) before scaling to full-scale HLD mines capable of 500,000 t/a each. The recovery methods used are based on solution mining: KCl-rich brine is produced from horizontal drill (HLD) wells, cooled in crystallizers to precipitate high-grade potassium chloride, then dewatered, dried, and either shipped as soluble product or compacted into granular MOP. The IPM, sited on Section 10-20-23W2 for proximity to roads, power, and natural gas, serves as a proof-of-concept to optimize mining and processing parameters. The full-scale plants (Disley West and Disley East) will incorporate compaction and glazing circuits to produce premium granular product. The process is designed to operate 330 days per year, with scheduled maintenance shutdowns. The recovery method relies on injecting heated brine (above 50°C) into underground caverns, dissolving potash ore, and recovering the saturated brine at 45°C. Two-stage crystallization drops the temperature from 45°C to 13°C, using barometric condensers and chillers, followed by centrifugation and rotary drying to achieve <0.2% moisture. This comprehensive potash recovery approach balances energy efficiency, product quality, and scalability, positioning BPC to meet growing global fertilizer demand.

Key Process Stages

• Stage 1: Brine Recovery and Injection – KCl-rich brine from production wells is received in tank T1100 with dilution water to prevent crystallization. Spent mother liquor from crystallizers, along with make-up water from the Mannville source well, is heated to over 50°C in brine injection tank T100 using a natural gas-fired boiler (BP001) and injected back into the cavern via pumps P001 and P002. This closed-loop circulation maintains cavern pressure and dissolves additional ore.
• Stage 2: Two-Stage Crystallization – Recovery brine at 45°C enters first-stage crystallizer X100, cooled to 32.5°C via barometric condenser BC100. The mother liquor then flows to second-stage crystallizer X101, where a chiller package CH100 and heat exchanger HE100 further cool the circulating brine to 13°C, inducing KCl crystallization. The slurry from both stages is combined and sent to centrifuge feed tank T105. The two-stage design allows heat recovery through the barometric condenser, reducing brine heating requirements.
• Stage 3: Centrifuging and Drying – Product slurry from crystallizer X101 is fed to screen bowl centrifuge C200 (IPM) or C1200/C1201 (full-scale) to dewater the KCl crystals to <5% moisture. The centrifuge cake drops into dryer feed screw SC200/SC1200 and enters a rotary dryer D200/D1200, which reduces moisture to <0.2%. Dryer exhaust is filtered through baghouse BH200/BH1200, with recovered dust returned to the product stream via screw and drag conveyors.
• Stage 4: Compaction and Glazing (Full-Scale) – For granular MOP production, dried product is sent to compactor feed bin T1401. Two compactors (CC1401/CC1402) produce flakes, which are broken by flake breakers FB1401/FB1402 and further crushed by CagePaktors (CR1401/CR1402). Oversize material is recycled via screens and bucket elevators. The granular product passes through a glazing water addition screw (1.5% w/w water) and a fluid bed dryer cooler to dry and cool to 80°C. Polishing screens remove oversize and fines, and dedust solution is applied before storage.
• Stage 5: Product Storage and Loading – Granular and soluble products are conveyed to dedicated storage buildings via belt conveyors and tripper systems. Reclaim is done by loader to a reclaim belt, screened to remove lumps, and weighed before loading into railcars or trucks. Soluble product is treated with 10% amine solution in screw conveyor SC301 (or SC1601 for full-scale) and bagged in 2 t bags or shipped as KCl brine. The loading weigh bin system ensures accurate dispatch.

Additional Interesting Data and Summary

The mass balance development for the Disley Project’s potash recovery methods is based on the KCl-NaCl-MgCl2-H2O system saturation data, using D’Ans solubility equilibria to determine component behavior at various temperatures. The IPM mass balance (Table 17.1) was used to size equipment for 125,000 t/a, detailing injection brine flow, recovery brine composition, and expected cavern dynamics including undissolved ore and brine losses to mining plane enlargement. The full-scale wet end mass balance (Table 17.2) for 500,000 t/a uses an average ore grade of 33.66% KCl, 0.55% carnallite, 6.64% insolubles, and remainder NaCl. The two-stage crystallizer system enables heat recovery via barometric condensers, reducing overall energy consumption for brine heating. Equipment sizing and performance are validated against established potash plants and original supplier data. Notably, BPC is evaluating a Vortex Crystallizer for low-temperature crystallization, which could reduce CAPEX and OPEX; pilot testing is anticipated during IPM operation. Environmental considerations include brine disposal wells for purge streams and a baghouse dust collection system for particulate control. The full-scale plants will have dedicated dust collection baghouses for compaction and glazing circuits. Product treatment involves amine solutions for soluble product (10% concentration at 60°C) and dedust oil for granular product, both requiring heated storage and mixing. The project’s economic impact is tied to its staged approach: the IPM de-risks technology and market entry, followed by simultaneous construction of two 500,000 t/a HLD mines (West and East) to capture economies of scale. Future outlook includes potential deployment of the Vortex Crystallizer and optimization of brine circulation. The Disley Project’s recovery methods demonstrate a robust, scalable solution mining process designed to produce high-purity MOP with flexible product forms (soluble and granular) to serve agricultural markets. The plant’s 330-day operating schedule with planned maintenance ensures high availability, while the closed-loop brine system minimizes freshwater consumption.

Key Processes: Crushing

Target Commodities: N/A