Rhoose

Rhoose Mitre Brand cement logo
Rhoose post-1919 "Mitre" brand.

Location:

Clinker manufacture operational: 29/4/1913-1979

Approximate total clinker production: 8.2 million tonnes

Raw materials:

Ownership:

The plant commenced as a private venture with what was at the time a fairly large rotary kiln, but was overshadowed from the outset by the larger and more advanced Aberthaw nearby. The kiln was a larger version of the well-described kiln installed at the same time at Masons. Taken over by Aberthaw in 1919, the decision to put in a second kiln of similar inefficiency to the first confirmed its role as make-up capacity for the Aberthaw plant. Through the depression years it was operated only for short periods, and it only began to run to capacity in 1936. The kilns shut down altogether from 17/08/1944 to 19/01/1946, during which time Vickers Desiccators and van der Werf coolers were installed.

The raw materials are essentially identical to those of Aberthaw, and were used in a similar manner. Initially the Blue Lias alone was used, removing the clay by selective crushing and screening. As higher C3S clinker became necessary, Ruthin quarry supplied limestone (CaCO3 92-96%) from 1947 to sweeten the mix, when Aberthaw and Blue Circle purchased the quarry as a joint venture. Subsequently, screening was abandoned and the entire un-sorted Lias was used.

The efficiency of the plant was improved in the 1960s with the installation of the third kiln. The reduction of slurry water content using deflocculants, as practiced everywhere at the time, was uniquely successful, with slurry moisture reduced from 38% to below 25% for a while until the resulting high sodium levels became a problem. The plant pioneered the production of low-heat clinker, commencing 8/4/1947, making 60,000 tonnes for the Claerwen Dam, in small batches over a four-year period. The naturally high silica ratio of the raw materials made this a straightforward process. The plant made sulfate resisting clinker alongside ordinary clinker from 1953 to 1980. Following the energy crisis, kilns 1 and 2 were stopped, and kiln 3 ceased making clinker in 1979, but during Blue Circle ownership 1983-9 the plant was used for slag drying and grinding. The plant used rail for transport. The company started its own asbestos-cement plant in the early 1930s, immediately to the west of the plant. It sold this to Turner & Newall Ltd in 1935. This plant continued in operation until 1992. Following this, the whole site was cleared. The cement plant and quarry are now largely under housing. The coastal part of the quarry has been developed as park land.

Please contact me with any relevant information or corrections. I am particularly interested in firmer dates and statistics.

Power supply

In the original plant, electricity was generated only for lighting and for the kiln, the rest being directly driven by steam engine. In 1923, the plant was entirely electrified, with power from turbo-generators sized to also provide back-up power to Aberthaw. Purchased power from the grid was used from 1939, but the power plant was retained as a back-up, and continued in use into the 1970s.

Rawmills

Combination ball mills were used:

Three rotary kilns were installed:

Kiln A1

Supplier: Polysius
Operated: 29/4/1913-1975
Process: Wet
Location: hot end 306617,166129: cold end 306553,166133: entirely enclosed.
Dimensions: metric (from end of cooling zone):

Rotation (viewed from firing end): clockwise
Slope: ?
Speed: ?
Drive: ?
Kiln profile (from end of cooling zone):

Cooler: there was no separate cooler.

Fuel: Coal: 1963-1972 Oil: Gas from 1972
Coal Mill: ?
Exhaust: initially via drop-out box to stack. From 1946 via four cyclones and ID fan to stack. From 1963 diverted to the inlet of No 3 electrostatic precipitators.
Typical Output: 1913-1944 149 t/d: 1946-1968 195 t/d: 1968-1975 165 t/d
Typical Heat Consumption: 1913-1946 8.45 MJ/kg: 1946-1968 7.45 MJ/kg: 1968-1975 8.35 MJ/kg


Kiln A2

Supplier: FLS
Operated: ?1/1923 to 1975
Process: Wet
Location: hot end 306618,166118: cold end 306554,166122: entirely enclosed.
Dimensions: metric (from end of cooling zone):

Rotation (viewed from firing end): clockwise
Slope: ?
Speed: ?
Drive: ?
Kiln profile (from end of cooling zone):

Cooler: as on Kiln A1
Fuel: Coal: 1963-1972 Oil: Gas from 1972
Coal Mill: ?
Exhaust: initially via drop-out box to stack. From 1945 via four cyclones and ID fan to stack. From 1963 diverted to the inlet of No 3 electrostatic precipitators.
Typical Output: 1923-1944 161 t/d: 1946-1968 211 t/d: 1968-1975 175 t/d
Typical Heat Consumption: 1923-1944 8.5 MJ/kg: 1946-1968 7.5 MJ/kg: 1968-1975 8.4 MJ/kg


Kiln A3

Supplier: FLS
Operated: 10/1963 to 1979
Process: Wet
Location: hot end 306749,166101: cold end 306613,166109: entirely enclosed.
Dimensions (from cooler ports): Metric 136.00 × 3.600BC / 3.950D
Rotation (viewed from firing end): anticlockwise
Slope: ?
Speed: ?
Drive: 186 kW
Kiln profile (from cooler ports): ?-4000×3600: 87000×3600: 90000×3950: 136000×3950: tyres at 3500, 31500, 62500, 94500, 123500: turning gear at 66000
Cooler: Unax planetary 10 × 11.50 × 1.400
Fuel: 1963-1972 Oil: 1972-1979 Gas
Exhaust: to ID fan then two parallel electrostatic precipitators to stack.
Typical Output: 1963-1975 710 t/d: 1975-1979 640 t/d
Typical Heat Consumption: 1963-1975 5.65 MJ/kg: 1975-1979 6.70 MJ/kg



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