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Precious Metal Granulator
Precious Metal Granulator
COOLDO precious metal granulators melt a measured batch and release the liquid metal through a controlled bottom outlet into water. The process converts gold, silver, copper, brass, bronze and compatible alloys into clean, manageable grains for refining, sampling, alloy preparation and rapid remelting. The latest standard range is CDO-MG10, CDO-MG20, CDO-MG35, CDO-MG45 and CDO-MG55.
Which granulator model should you choose?
For small jewelry, laboratory and refining batches, start with CDO-MG10 or CDO-MG20. CDO-MG35, CDO-MG45 and CDO-MG55 are production machines for larger silver, gold and copper batches. Capacity must be checked by metal: the same crucible volume holds different weights of gold and silver. Grain shape is not determined by model number alone; outlet size, melt temperature, alloy fluidity, discharge rate, falling distance and water condition must be set together.
How the precious metal granulation process works
Charge and melt
Clean metal is charged into a compatible graphite crucible. Medium-frequency induction heating melts the batch and creates electromagnetic circulation for a more uniform bath.
Condition the melt
The operator confirms temperature and removes unsuitable surface contamination. Nitrogen or argon can reduce oxidation; stirring is considered when alloy segregation is a concern.
Control the discharge
A stopper rod opens the bottom outlet. The nozzle diameter, head pressure and opening rate control the stream before it breaks into droplets.
Quench and collect
Droplets solidify in the water tank and fall into a removable collection basket. Grains are drained, dried and screened before the next operation.
Latest standard precious metal granulator models
| Model | Power | Gold capacity | Silver capacity | Melting time | Granulating time |
|---|---|---|---|---|---|
| CDO-MG10 | 10 kW | 2–4 kg | 1–2 kg | 2–5 min | About 5 min |
| CDO-MG20 | 25 kW | 8–10 kg | 4–5 kg | 5–8 min | About 10 min |
| CDO-MG35 | 35 kW | 40 kg | 20 kg | 10–15 min | About 15 min |
| CDO-MG45 | 45 kW | 60 kg | 30 kg | 10–20 min | About 20 min |
| CDO-MG55 | 55 kW | 100 kg | 50 kg | 20–30 min | About 30 min |
Capacity note: Published figures are model-selection references. Usable capacity and cycle time change with metal density, alloy, charge shape, safe crucible level, utilities and production method.
Electrical, size and installation reference
| Model | Electrical supply | Machine size | Approx. weight | Granulation method |
|---|---|---|---|---|
| CDO-MG10 | 380 V or 220 V, 3-phase, 50/60 Hz | 1000 × 500 × 965 mm | 150 kg | Gravity discharge |
| CDO-MG20 | 380 V, 3-phase, 50/60 Hz | 1150 × 500 × 1100 mm | 270 kg | Gravity discharge |
| CDO-MG35 | 380 V, 3-phase, 50/60 Hz | 1610 × 1550 × 1930 mm | 600 kg | Gravity discharge |
| CDO-MG45 | 380 V, 3-phase, 50/60 Hz | 1610 × 1550 × 1930 mm | 700 kg | Gravity discharge |
| CDO-MG55 | 380 V, 3-phase, 50/60 Hz | 1610 × 1550 × 1930 mm | 750 kg | Gravity discharge |
Granulator configurations from workshop to refinery scale
These views show why the machine layout changes with batch size and atmosphere requirement. Each image is paired with a selection point instead of being used as decoration.
Configuration, applications and project planning
What the standard machine includes
- IGBT induction power supply and matched melting furnace.
- Bottom-discharge crucible, stopper rod and replaceable outlet components.
- Water granulation tank with removable collection basket.
- Cooling-water circuit and electrical protection according to model.
- Optional inert-gas cover, mechanical stirring or vacuum configuration after technical review.
Information required for selection
- Metal or complete alloy composition, including karat gold and copper content.
- Normal and maximum batch weight plus required batches per shift.
- Purpose of the grain: refining, sampling, alloying or direct remelting.
- Acceptable grain-size range and whether narrow uniformity is essential.
- Local voltage, cooling-water conditions, destination and installation restrictions.
Applications and downstream use
- Gold and silver refining feed preparation.
- Homogeneous alloy charges for jewelry and bullion production.
- Sampling and batch division before laboratory analysis.
- Copper, brass and bronze grain preparation within the confirmed process range.
- Fast remelting feed for continuous casting or vacuum casting lines.
Important operating limits
- Mixed, wet or contaminated scrap must be prepared before charging.
- Outlet parts and crucibles are consumables and must match the metal.
- Water temperature and cleanliness affect cooling and grain appearance.
- The collection basket must be fully drained and grains dried before storage.
- Published cycle times are references, not guaranteed output for every alloy.
Frequently asked questions
What models are included in the current standard granulator range?
The standard catalogue range used on this page is CDO-MG10, CDO-MG20, CDO-MG35, CDO-MG45 and CDO-MG55. Any older or custom reference should be confirmed before quotation.
What controls the finished grain size?
Outlet diameter, molten-metal temperature, alloy fluidity, discharge speed, falling distance, water depth and water temperature work together. A model number alone cannot guarantee one particle size.
Can one machine granulate both gold and silver?
Yes, within the published capacity and temperature range. Dedicated crucibles and outlet components are recommended when purity and cross-contamination control are important.
Can it process copper, brass or bronze?
Yes, compatible copper alloys are possible when power, crucible, outlet material, atmosphere and cooling conditions are confirmed for the actual composition.
When is mechanical stirring required?
Stirring is considered for alloy preparation where density differences or segregation may reduce batch uniformity. It is not automatically necessary for every pure-metal granulation process.
When should vacuum or inert gas be selected?
Nitrogen or argon is commonly used to reduce oxidation. A sealed or vacuum configuration is evaluated for oxidation-sensitive materials or tighter atmosphere control.
Does the granulator include a water chiller?
The machine requires a stable cooling circuit. The final quotation states whether a water tank, pump or industrial chiller is included and sized for the duty cycle.
What should be sent for a quotation?
Send alloy composition, normal and maximum batch, desired grain range, daily output, voltage, water conditions, destination country and any atmosphere or stirring requirement.
Confirm the correct configuration before quotation
Send COOLDO the metal or alloy, normal and maximum batch, target product, daily output, local voltage, cooling conditions and destination country. The engineering team will confirm the machine, consumables, utilities, installation scope and optional equipment before quotation.