Report - - Winnington Calcium Chloride Plant (Cheshire, Mar, 2019) | Industrial Sites | 28DaysLater.co.uk

Report - Winnington Calcium Chloride Plant (Cheshire, Mar, 2019)


28DL Regular User
Regular User
While in Northwich to have a look at the hydraulics of the Anderton Boat Lift I was sitting outside the cafe looking at the chemical works opposite, thinking quite a lot of it seemed to be derelict.

Indeed the name Winnington rang a bell and a quick Google revealed that this site and the other one in nearby Lostock have been urbex playgrounds for years.

I could even see the door to nowhere saying ‘System Control Room’, the only remaining part of the Winnington B power station.

There were a few hours of daylight left so I headed across the River Weaver towards the nearest derelict part, a tall, wrecked-looking shed which hasn’t featured before in previous reports.

This turned out to be the calcium chloride (CaCl2) plant for the soda ash works.

CaCl2 is the byproduct from the Solvay process: brine plus limestone gives sodium carbonate (soda ash) plus CaCl2.

Maps suggest the building may date from the 60’s.

Now CaCl2 is pretty dull stuff - it’s not remotely toxic and doesn’t go bang - but it has enough uses for it to be worthwhile recovering.

For reference these are, inter alia,

- alginate products (food, medicine)
- crude oil production (drilling muds)
- refrigeration and de-icing (29% w/w CaCl2 doesn’t freeze until - 53oC)
- agriculture (spray for apple trees)
- water treatment (mineral balance, creamy head on beer)

All this plant did was to take the effluent stream, or ‘distiller blow off’, from the Solvay process containing ca. 11% w/w CaCl2 in water, clean it up and concentrate it to 35% w/w.

Various grades of concentrate were then tankered off to a Henty storage facility at the Liverpool docks - Henty is a familiar name from Liverpool dockside rambles.

First up, reception and control.

Found a copy of the operating manual, pulled up a chair and settled down for a good read.

The story starts down by a weir on the river where Solvay effluent was pumped into tanks visible on the right, allowing some of the less soluble impurities (lime) to settle out.

The crude liquor was then pumped up to the top of the plant through two evaporators connected in series - large hollow vessels where steam flashed off.

A view of the top evaporator from the back of the plant showing the spaces where more of these pairs of evaporators may once have lived.

Outside and inside one of the evaporators.

The liquor itself was heated by in-line heat exchangers with downgraded steam from the local power station (presumably Winnington B).

A view down to a couple of these heat exchangers, which may have been taken out for descaling or salvage.

Concentrations were monitored by density - one of the pots of hydrometers on the right.

The main impurity in the crude liquor was common salt (ca. 5% w/w), which starts to come out of solution when the CaCl2 is concentrated.

This salt was allowed to settle out in thickeners - the conical vessels at the top of this picture …

..with the salty slurry running down to rotary vacuum drum filters far below.

There’s a lot more kit associated with the process - the evaporated steam for example had to be condensed, and the second concentration stage was under reduced pressure with two separate venturi-based vacuum systems.

Now we go on a tour of the rest of the building from the ground up pointing out a few of the other ‘interesting’ things. Power for the evaporators.

Several settling tanks outside the plant where concentrate deposited more impurities after the addition of flocculant.

The small black tank just left of centre is a carbon filter for the final clarification stage.

The sludge from various stages eventually got pumped back down the boreholes from which the brine for the soda ash process was extracted in the first place.

Pumps for river water which was used for condensation, vacuum and general washing purposes.

Tank for condensed steam.

A series of girder-ey vistas…

….and up to the crane.

…for a partial view of the rest of the soda ash plant.

The long red brick building bottom left is the former head office, Mond House (mostly empty modernized offices inside).

A final view of the plant from on top of a large stock tank down by the river capable of holding 6500 tonnes of concentrate.



Staff member
Good stuff, ended up having a right run for money with security at the live bit of Winnington years ago, ended up covered in the white stuff and saw virtually bugger all for our troubles haha, did the derpy bit but not quite the same appeal.


28DL Regular User
Regular User
Nicely done mate. Theres loads to see here but everytime I’ve been it’s gone dark on me and never bothered with photos :-( good to see some photos of it.