Phosphate sludge

The Vacuum Filter dirt separator is able to filter the water (bonder) polluted by the sludge coming from a phosphating tank, allowing to obtain on the one hand the clear liquid to be put back in the tank and on the other a dry waste of easy management.

This also entails a considerable reduction in disposal volumes. Scraper blade machines are usually used for the muddling, while a dialysed Precoat filter is indicated for the continuous cleaning of the bath. In most cases small filters are used: 0.5 and 1.2 Mq.

The system differences substantially compared to traditional dirt separators, especially for the extremely low operating cost. The range of Vacuum Filter systems range from 0.5 to 3.4 Mq of filtering surface.

One of the major problems inherent in phosphating baths is the presence of slime. This fact is the cause of more or less frequent stops of the plant for de-mining and cleaning operations, with consequent loss of time, material and money.

The possibility to perform a continuous filtration of the bath or as needed, using our “Vacuum Rotary” filter, offers the following notable practical and economic advantages:

  1. Reduction of the total amount of sludge (the vacuum filter performs a partial sludge drying).
  2. Recovery of the amount of bath that is normally evacuated with the sludge; normally this quantity is about 60% of the total evacuated.
  3. A consequent lower consumption of phosphating product (the saving percentage can be quantified between 10% and 20% of the total product consumption).
  4. Less quantity of sludge to be purified with traditional lime system; therefore lower cost for the evacuation of the same.
  5. Labor saving: filtration can be performed during the working period with the bath in operation.
  6. Better quality of the phosphated product (for example: the sludge deposited on wires to be drawn is a major obstacle to lubrication).
  7. Great work economy: once started, no intervention is required in practice.
  8. High filtration potential. With a 10,000 liter bath, weekly 5 to 10 hours of filtration are required.
  9. Extreme manageability and versatility of the filtering system. Given its compactness and lightness, it can be transported to several points of the factory to perform different types of filtration.
  10. Possibility of working both hot and cold: to speed up the filtration operation it is possible, on the plants provided with a decanter, to filter from the bottom of the decanter and recycle the clear directly into the bathroom.

Application examples


This filter is installed in parallel with the phosphating tanks, inside a tube production line.
The system allows continuous bath cleaning on the 8 hours of daily work.



Automatic loading and reloading pumps and programmed blade feed.
Integrated washing system


disposal. It obtains a very dry and easily managed residue, and a clear solution that can be reused in the phosphating process.


With the dirt separator it is possible to carry out continuous cleaning cycles of the dialysis bath, or to filter the thick sludge coming from the decanter or the tank bottom.


The construction of the systems is completely carried out within the company with top quality materials.The machine is produced in stainless steel AISI 304 or 316 on request. This guarantees a long life to the system even in critical conditions.


The whole range is also produced in automatic execution, with pneumatic valves and solenoid valves controlled by a PLC with a touch screen integrated in the control panel.
On request we can execute plants of any size.


Our systems can be customized.
Each system is designed and built taking into account the particular requests and needs of the individual customer.