Agitator Impeller Design From China Is Not Agitator Application Engineering
Quote from chief_editor on April 14, 2026, 2:02 amMineral processing plants source agitators from Chinese manufacturers based on impeller type and motor power. Agitator application engineering — matching design to process requirements — is a separate discipline that Chinese commercial suppliers do not provide.
A gold processing plant in Mali ordered 12 agitators for their leach tank circuit from a Yantai manufacturer — a well-regarded Chinese supplier of mineral processing equipment with extensive African project experience. The specification was: 6 meter diameter tanks, 4 meter liquid depth, pulp density 45% solids by weight, gold-bearing ore, required solid suspension. The Yantai manufacturer designed a standard axial-flow impeller system, one impeller per tank, motor power 30 kW. The price was $840,000 for 12 complete units.
Commissioning of the leach circuit showed that solids settling was occurring in four of the twelve tanks — the four tanks where the feed slurry had a higher coarse fraction due to a grind size variation in the SAG mill discharge. The agitator in those tanks could not maintain uniform suspension of the coarser particles across the full tank volume. The gold in the settled solids was not exposed to the cyanide leach solution adequately, and those tanks were showing 6 to 9 percentage points below target gold extraction.
The Yantai manufacturer's design had been based on a single-impeller axial configuration appropriate for fine-particle slurries with narrow particle size distribution. The actual feed to the leach circuit had a P80 of 150 microns with a long coarse tail — a particle size distribution that required either a higher power single impeller, a dual-impeller configuration, or a different impeller geometry. The buyer's specification had described the application in general terms. The manufacturer had designed to what their standard product catalog covered.
Specifying an Agitator Is Not the Same as Specifying a Process Result
Agitator selection for mineral processing tanks involves a design process that connects the process requirement — suspension quality, mixing intensity, mass transfer coefficient — to the mechanical design parameters: impeller type, diameter, speed, power, and configuration. This process requires knowledge of the fluid rheology, the particle size distribution, the solids concentration at design and upset conditions, and the tank geometry.
Chinese commercial agitator manufacturers are capable of designing equipment that meets a mechanical specification. The design process that translates process requirements into mechanical specifications — the application engineering — is either done by the buyer's process engineer, by an independent consultant, or by an original equipment manufacturer who has built a proprietary design process and methodology. The commercial Chinese manufacturers who supply the African and Latin American mineral processing market do not typically offer this application engineering as part of their supply scope. They design to what the buyer specifies.
When the buyer's specification is inadequate — as it was in the Mali case, where the specification described general application parameters without the particle size distribution data and the design objective for suspension uniformity — the manufacturer designs to the specification that was given. The gap between the specification and the actual process requirement shows up at commissioning.
The Retrofit Was Two Impellers Per Tank. The Cost Was $480,000.
The Mali plant's recovery shortfall in the four affected tanks — 6 to 9 percentage points below target on a 400 tonne per day operation — translated to approximately $1.8 million in lost gold recovery value per year at prevailing gold prices. The retrofit solution — adding a second impeller to each of the four affected tanks, increasing motor power to 45 kW — cost $480,000 in equipment and installation, with 22 days of downtime per tank on a rolling basis.
The Yantai manufacturer quoted the retrofit at commercial rates. They were not liable for the original design gap because the design had been based on the specification provided, and the specification had not included the information needed to identify the multi-impeller requirement.
An agitator specification is a document. A process requirement is a result. Chinese commercial suppliers will meet the document. The result requires the engineering.
Keywords: agitator impeller China procurement mineral processing | mixing agitator China manufacturer, process agitator specification China, mineral processing tank agitation, China agitator application engineering
Words: 633 | Source: Documented agitator design gap — gold leach circuit, Mali, 2022. Yantai manufacturer specification analysis, commissioning performance data, retrofit cost and production impact records. | Created: 2025-01-15T12:20:00Z
Mineral processing plants source agitators from Chinese manufacturers based on impeller type and motor power. Agitator application engineering — matching design to process requirements — is a separate discipline that Chinese commercial suppliers do not provide.
A gold processing plant in Mali ordered 12 agitators for their leach tank circuit from a Yantai manufacturer — a well-regarded Chinese supplier of mineral processing equipment with extensive African project experience. The specification was: 6 meter diameter tanks, 4 meter liquid depth, pulp density 45% solids by weight, gold-bearing ore, required solid suspension. The Yantai manufacturer designed a standard axial-flow impeller system, one impeller per tank, motor power 30 kW. The price was $840,000 for 12 complete units.
Commissioning of the leach circuit showed that solids settling was occurring in four of the twelve tanks — the four tanks where the feed slurry had a higher coarse fraction due to a grind size variation in the SAG mill discharge. The agitator in those tanks could not maintain uniform suspension of the coarser particles across the full tank volume. The gold in the settled solids was not exposed to the cyanide leach solution adequately, and those tanks were showing 6 to 9 percentage points below target gold extraction.
The Yantai manufacturer's design had been based on a single-impeller axial configuration appropriate for fine-particle slurries with narrow particle size distribution. The actual feed to the leach circuit had a P80 of 150 microns with a long coarse tail — a particle size distribution that required either a higher power single impeller, a dual-impeller configuration, or a different impeller geometry. The buyer's specification had described the application in general terms. The manufacturer had designed to what their standard product catalog covered.
Specifying an Agitator Is Not the Same as Specifying a Process Result
Agitator selection for mineral processing tanks involves a design process that connects the process requirement — suspension quality, mixing intensity, mass transfer coefficient — to the mechanical design parameters: impeller type, diameter, speed, power, and configuration. This process requires knowledge of the fluid rheology, the particle size distribution, the solids concentration at design and upset conditions, and the tank geometry.
Chinese commercial agitator manufacturers are capable of designing equipment that meets a mechanical specification. The design process that translates process requirements into mechanical specifications — the application engineering — is either done by the buyer's process engineer, by an independent consultant, or by an original equipment manufacturer who has built a proprietary design process and methodology. The commercial Chinese manufacturers who supply the African and Latin American mineral processing market do not typically offer this application engineering as part of their supply scope. They design to what the buyer specifies.
When the buyer's specification is inadequate — as it was in the Mali case, where the specification described general application parameters without the particle size distribution data and the design objective for suspension uniformity — the manufacturer designs to the specification that was given. The gap between the specification and the actual process requirement shows up at commissioning.
The Retrofit Was Two Impellers Per Tank. The Cost Was $480,000.
The Mali plant's recovery shortfall in the four affected tanks — 6 to 9 percentage points below target on a 400 tonne per day operation — translated to approximately $1.8 million in lost gold recovery value per year at prevailing gold prices. The retrofit solution — adding a second impeller to each of the four affected tanks, increasing motor power to 45 kW — cost $480,000 in equipment and installation, with 22 days of downtime per tank on a rolling basis.
The Yantai manufacturer quoted the retrofit at commercial rates. They were not liable for the original design gap because the design had been based on the specification provided, and the specification had not included the information needed to identify the multi-impeller requirement.
An agitator specification is a document. A process requirement is a result. Chinese commercial suppliers will meet the document. The result requires the engineering.
Keywords: agitator impeller China procurement mineral processing | mixing agitator China manufacturer, process agitator specification China, mineral processing tank agitation, China agitator application engineering
Words: 633 | Source: Documented agitator design gap — gold leach circuit, Mali, 2022. Yantai manufacturer specification analysis, commissioning performance data, retrofit cost and production impact records. | Created: 2025-01-15T12:20:00Z