A stable solution for turbulent times

Kalic Liquid Lime offers an advanced treatment for acidic effluent waste that is safe, inexpensive and environmentally friendly. Richard Givens at Buxton Lime Industries, explains how.

Kalic Liquid Lime is an advanced lime-based treatment for acidic effluent waste and drinking water. Since its introduction, Kalic has proved to be not only a safer alternative than caustic soda, but also more economic. In a relatively short space of time, Kalic has become a highly regarded chemical agent, the product of a unique and innovative manufacturing process which was developed after many years research and market experience. Needless to say, it is exclusive to Buxton Lime Industries (BLI).

For centuries, high grade carboniferous limestone from the Derbyshire Peak District has been used for the manufacture of lime products. This very same natural resource of exceptional purity is also used to manufacture Kalic. The result is a fast reacting liquid product which comprises an 18 per cent micron-sized suspension of calcium hydroxide in water. The extremely small particles make for a stable suspension with a large surface area to give rapid reactivity and high efficiency for acid neutralisation and pH control.

Kalic is produced by reacting calcium oxide with water, but it should not be confused with ordinary milk of lime or lime slurry materials. No other chemical additives are needed to stabilise the solution. The result is an extremely stable product which is safe and easy to handle. This may explain why Kalic's tried and tested formulation has been applied to a wide range of industries which include water, steel production, oil, pharmaceuticals, food processing and agri-chemicals.

User friendly

Kalic is a user friendly solution. In place of the hazards, corrosiveness and handling problems normally associated with caustic soda, Kalic's non-toxic and non-corrosive suspension of calcium hydroxide is classed simply as an irritant, leading to lower handling costs. Personal protection requirements and overall levels of safety hazard are much reduced compared to caustic soda. Kalic combines a less aggressive, more environmentally friendly formulation that also gives superior performance.

However, its benefits do not stop there. Kalic does not need to be stored in special containers and can be kept in mild or stainless steel as well as most plastics. But it also helps to protect tanks, vessels, valves and pipework from corrosion. This means plant and machinery are less likely to be damaged. Furthermore, the low freezing point (0oC) reduces the need for lagging and trace heating of pipework, pumps and tanks. In contrast, caustic soda is not cheap to handle or store. It is typically used at a freezing point of around 9oC and requires tanks which have to be lagged and heated for approximately nine months of the year.

Kalic does not exhibit the wild price fluctuations associated with the supply of caustic soda.

This is because caustic soda is only manufactured as a by-product of chlorine and is therefore linked to its production. Recent falls in chlorine production have led to dramatic price hikes, sometimes as high as 50 per cent. In fact, over the past three years, the delivered cost per tonne of caustic soda has suffered dramatic rises and falls. In contrast, over the same period, Kalic has shown remarkable stability. This is because it is based on a readily available natural material, is unaffected by such market trends and so exhibits a more favourable and stable price structure.

Water treatment

Such benefits have clearly influenced Severn Trent Water. It recently opted to install a Kalic system to carry out the lime dosing requirement at its Church Wilne works in order to secure compliance with current and anticipated water supply standards, and to obtain best standards of operational reliability and efficiency. What has resulted is the largest Kalic system so far installed at any water treatment works. The programme of work included replacing and upgrading the chemical dosing systems, the largest of which is the lime dosing system.

Lime dosing is primarily required to correct final pH prior to water entering supply pipelines. A secondary requirement for lime dosing arises if incoming water contains high levels of organic matter (normally at certain times during the summer), requiring acid dosing to improve coagulation (solids removal) from the raw water. Lime is then dosed to optimise pH prior to filtration via RGF (rapid gravity filters) as well as the ongoing lime requirement for final pH adjustment. The same system can also be used to enhance removal of manganese if required, again by dosing lime ahead of the RGF system.

Following successful trials in 2001, Birds Eye Walls decided to switch to Kalic Liquid Lime in place of caustic soda at its Phoenix ice cream factory in Gloucester because it required an effective agent to neutralise process effluent. This included a cocktail of milk, vegetable oils and fats, plus a sprinkling of food particles, sugars, milk powders, flavourings, other ingredients and trace quantities of cleaning chemicals. Though not toxic, this could not be discharged into the environment without proper modification.

Continuous improvement

Paul Finch, Environmental Officer at Walls explains the decision: "The use of Kalic is one way in which we want to comply and seek continuous improvement within both ISO 14001 and the policy of our parent group, Unilever. Kalic has provided us with a good, positive environmental impact, as well as cost savings. We anticipate payback in less than a year as Kalic costs significantly less than bulk caustic soda and is also far more user friendly."

Other prominent Kalic users include BMW Manufacturing UK at the new Mini production site at Cowley, which is currently being fitted with a Kalic effluent treatment system. All these users have benefited directly from the ISO 9002 quality assurance which covers the manufacture of Kalic Liquid Lime under a process which is environmentally credited to BS 14001.



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