UK lime’s green credentials

By Jessica Roberts
Published: Monday, 26 October 2009

British lime producer Francis Flower is striving for wider uptake of recycled aggregate products

Somerset, UK-based Francis Flower, the trading company of Gurney Slade Lime & Stone Co. Ltd, is a family business focused on the mining, processing, and supply of limestone and lime products. The Francis Flower Group, which has roots back to the 1950s, comprises a number of strategic depots placed throughout the UK, in locations such as Runcorn, near Liverpool, Ely, near Cambridge, and Gurney Slade, near Bristol.

Francis Flower’s depots facilitate the delivery of lime powders across the UK, but also accept imported material for further processing, and specialist minerals from Europe and North Africa. Strategic locations near ports also enable the group’s mineral products to be exported easily to nearby Ireland, Europe and the Eastern hemisphere.



Francis Flower has production distribution of
more than 200,000 tpa. Pictured is CEO Adrian Willmott.
Courtesy Francis Flower

Limestone fillers

In the early 1980s the demand for asphalt began to grow significantly as the UK’s road network was expanded and upgraded. For asphalt manufacturers this boom time was tempered with the problem of balancing the generation of filler when producing base and binder courses with the demand when mixing surface courses.

As few asphalt plants had enough on-site storage to be self sufficient, Francis Flower devised a solution by the strategic placement of filler storage silos across England, Scotland, and Wales, accompanied by a centrally controlled road distribution function within its customer services department.

Presently, the company’s silo storage capacity for filler materials is 30,000 tonnes, with individual silos ranging from 70 tonnes capacity up to 1,200 tonnes. Overall, Francis Flower’s distribution of filler minerals exceeds 200,000 tpa.

At strategic silo locations the company has installed modern remote monitoring devices Ð provided by Dedicated Engines Ltd and Minsterport Ltd Ð whereby the contents of silos are displayed via a web portal. Using this equipment, Francis Flower can monitor usage, low and high levels, and delivery and collection times, in addition to an automatic alarm system that is connected to the customer services desk.

In addition, by looking at previous volumes used, the system can predict when further deliveries should be made.

Secure web portals are made available to customers who are interested in monitoring the vendor managed inventory (VMI) link in their supply chain. To withstand Europe’s highest density of HGV and car traffic, modern asphalt has been designed as a technical material that is made precisely from quality assured materials.

Supporting this, Francis Flower operates a third party accredited quality assurance scheme, which ensures that its filler materials meet customers’ technical needs. As the company told IM, customers’ priorities, however, have increased beyond the physical properties of aggregates.



Products are available in bags up to one tonne in size.
Courtesy Francis Flower

Environmental awareness

Public companies are becoming increasingly aware of corporate and social responsibility, and organisations now wish to procure goods and services that reduce the environmental impact of their own operations.

Francis Flower claims that it is able to assist in this, by providing SGS-certified recycled filler minerals (under BS EN ISO 14021:2000); enabling its clients to declare that they are using recyclable materials in their processes. Many consumers of industrial products are following the Building Research Establishment’s criteria of requiring minimum contents of recycled ingredients.

Further, Francis Flower’s detailed tracking of collection and delivery movements enables the company to demonstrate that over their national businesses, its customers receive goods that have travelled fewer miles than would be possible from their own internal supplies or virgin milled powder. Francis Flower’s recycled filler will carry the mobulus loop infinity symbol in declaration of its credentials.

Material sources

Manufactured filler is available from Wicken Lime & Stone Co. Ltd based near Cambridge, where oolitic limestone is quarried and milled. Wicken operates three mills and 10 finished product silos. The mill has a capacity of some 70,000 tpa and additionally supplies around 7,000 tpa of agricultural lime.

Francis Flower’s Gurney Slade operation receives and processes a variety of coarse and fine minerals using three main procedures. The company uses a Bradley Pulverizer machine to grind and classify material, while any materials with high silica content undergo further processing via a ball mill. The final process is screening through a Mogensen sizer.

Limestone fillers, bentonite clays and other minerals can be ground, blended, and bagged into 25kg or 1 tonne big bags, or stored as bulk products in any of the 10 silos which offer 3,200 tonnes of storage capacity. The facility has UFAS accreditation which enables it to process agricultural feeds and compounds.



The company provides a number of SGS-certified
recycled filler minerals. Courtesy Francis Flower

Subsidiaries

The Fertilizer Co. is a wholly own subsidiary of Gurney Slade Lime & Stone, with a 40,000 tpa business located on Runcorn docks in Cheshire, UK. Bulk vessels up to 3,000 tonnes are easily loaded at Runcorn for overseas clients.

The Fertilizer Co. manufactures Calcifert; a finely ground limestone combined with a water soluble organic binder to produce hard 2-5mm size particles. Owing to the manufacturing process, Francis Flower claims that controlled amounts of trace elements can be added into the granules to provide an enhanced product.

The company also produces bespoke granules, predominantly formed of calcium sulphate (but if required, also with a various mix of nutrients). Finished goods are available in 25kg bags or bulk, or in non-returnable 600kg bags.

Francis Flower (Northern) Ltd, also based on Runcorn docks, processes UK-derived synthetic anhydrite and material imported from Europe and Africa. The plant was installed in 2004 and operates four mills with a production capacity in excess of 140,000 tpa.

Anhydrite is available as milled powder or unmilled granules (nominally 6mm to dust) and it can be packaged in 1 tonne or 25kg bags, or supplied bulk in tippers and powder tankers.

Runcorn depot also hosts Francis Flower’s central laboratory, which provides specialist testing services to the Francis Flower Group and its regional testing stations at Gurney Slade and Wicken. A full range of tests including compressive and flexural strength testing, flow, setting time and determination of particle size and particle specific surface (Blaine), enables the laboratory to measure the properties of anhydrite and other materials.

Making the optimum use of recycled materials is becoming increasingly important to many organisations. The company’s anhydrite can be labelled as being 100% recycled in accordance with EN ISO 14021, enabling customers to use this accreditation regarding the recycled credentials of the constituents of their own products.