Water

What it is for

Closing the plant water balance: fresh water, recovered water, sprays, washes and dilutions. All water that enters the process outside the Feeds appears in the closure, so the difference comes to zero.

The four ways to add water

In all of them, water is only added. No feature removes water on its own: if the % solids target would require removing water, nothing is added and the balance warns.

Water feed

1. Insert a Water feed ("Feed and product" group). The line comes out blue.
2. Enter the Water flow rate (m³/h).

The balance summary shows how much of the water comes from the water feeds, for example "water 170 → 170 m³/h (includes 70 m³/h from water feeds)".

Water addition

Insert a Water addition ("Tanks, vessels and mixing" group) in the middle of the line and choose one option — only one can be filled in:

• To % solids: adds the water needed for the outlet stream to reach the requested %;
• Fixed flow rate (m³/h).

Water intake

Units that receive water separately from the feed have a water intake: a small inlet with a blue segment and the label "water", standing in for the actual piping.

Units with an intake: Magnetic separators (WHIMS and VHGMS), Ball mill, Vibrating screen, inclined, dewatering and DSM screens, rotary screen, wet magnetic drum, spiral, jig and flotation column.

Cyclone, hydrocyclone and hydrosizer do not have an intake.

How it works:

• Nothing connected to the intake: the water the unit requires appears in the closure as added at the unit ("Added water — …").
• A Water feed connected directly to the intake: the Water feed flow rate becomes automatic — equal to what the unit requires. Its panel becomes read-only and the value shows in black in the table (it is not specified). In the closure, the water now counts as a water feed.
• The intake accepts one Water feed, connected directly. A stream with solids coming from another unit, or two feeds on the same intake, give an error.

The unit panel shows Water through the intake and what it represents (the screen spray, the water for the mill to reach its % solids, the external water per t/h of feed, etc.).

Water in the WHIMS

This also applies to the VHGMS. The WHIMS has a single intake; through valves, it is split between the magnetics wash and the middlings wash. In the panel:

• Magnetics moisture (entrainment): the feed water that the magnetics carry with them, in % of wet mass. This water comes from the feed, not from the intake.
• Solids in magnetics (% solids): the water needed beyond entrainment is the magnetics wash (fresh water, through the intake). If the requested % is drier than the entrainment moisture, the wash is zero and the balance warns.
• Middlings wash:
  • without a separate middlings product, in m³/h per t/h of feed; it goes down with the non-magnetics;
  • with middlings product (MD), by middlings % solids or per t/h; it goes to the middlings.
• Middlings moisture (entrainment), only with a middlings product: like the magnetics one, the feed water that the middlings carry, as % of wet mass (a new WHIMS starts with the same moisture as the magnetics). By middlings % solids, the middlings wash is the water needed beyond the entrainment (zero, with a warning, if the requested % is drier than the moisture); per t/h, the wash adds to the entrainment. Blank: the middlings carry no water.
• Non-magnetics: takes the feed water minus the magnetics and middlings entrainment (plus the middlings wash, when there is no separate middlings).
• The intake requires the sum of the washes.

Older projects: WHIMS saved before this model keep the previous water model ("Magnetics leave with spray water", middlings spray and separate wash water). Their panel offers Use the single water intake to switch to the current model.

Water in the other units

• Vibrating screen: single spray, through the intake, in m³/h per t/h of feed or as a fixed flow (m³/h). The oversize of each deck leaves at the requested % solids; the undersize takes the rest. Lack of water is warned per deck.
• Catalog screens (inclined, dewatering, DSM, static, grizzly, trommel, mobile): the same rule as the vibrating screen. The oversize (in the mobile screen, coarse and medium) leaves at its % solids, 85 % when the field is left blank, and the undersize takes the rest: feed water + spray − water in the oversize. Older projects with a % solids stored on the undersize are calculated by the new rule, with a warning that the value was ignored.
• Mass splits: % solids of one of the outlets (the other takes the rest) and spray in m³/h per t/h of feed or as a fixed flow (m³/h).

When you switch the spray form, the editor converts the current water using the feed of the last calculation: 1.5 m³/h per t/h with 20 t/h of solids becomes 30 m³/h, and the other way round. With a fixed flow, the water does not follow the feed.

• Hydrocyclone, cyclone and hydrosizer: underflow % solids (65 % when blank); the overflow takes the rest. Older projects with the water to underflow or with the overflow % solids are calculated by the new rule and warn until the underflow % solids is entered.
• Thickener: underflow % solids; the overflow takes the rest.
• Filter: cake moisture; the filtrate takes the rest.
• Ball mill: water to the discharge % solids (optional).

Tips

• Use a Water feed for water with an identifiable source in the plant (fresh water, recovered water). Use a Water addition for a dilution point in the middle of a line.
• To see the fresh water consumption of an area, connect Water feeds to the intakes: the closure then lists each one.

Common warnings and limits

• "Not enough water": a product required more water than the feed has. Add water upstream or review the % solids.
• There is not yet a process water tank with automatic make-up (make-up water = consumption − recovered water). Calculate the make-up from the closure.
• Water rules specific to the spiral and the jig (beyond the external water per t/h) and practical limits of the WHIMS do not exist yet.