LECA IS A Ceramic aggregates are made by heating shale, clay, or slate to temperatures in excess of 1000 to 1200 degrees in a rotary kiln. This process, called “pyroprocessing”, causes the material to expand into a synthetic lightweight aggregate, according to the Expanded Shale, Clay and Slate Institute.

“The process produces a high quality ceramic aggregate that is structurally strong, physically stable, durable, environmentally inert, light in weight, and highly insulative,” Gary says. “It is a natural, non-toxic, absorptive aggregate that is dimensionally stable and will not degrade over time."

Clay is a very fine-grained, moisture-retentive, naturally occurring material composed principally of silicates of alumina, derived from the decay of igneous micas and feldspars, such as found in granite. Common clay is a sticky, plastic type of sedimentary rock that is composed primarily of varying amounts of clay minerals, quartz sand, calcite, iron oxides, organic impurities and other materials

Clay may occur in a wide variety of colors depending upon its mineralogical composition, impurities, and the amount of weathering which it has undergone.

Their cellular pore system gives these lightweight aggregates their low-particle relative density. “The cellular structure within the particles is normally developed by heating certain raw materials to incipient fusion,” the institute says. “At this temperature, gases are evolved within the pyroplastic mass, causing expansion, which is retained upon cooling."

The resulting aggregates have uniformly distributed pores with a size range of 5 to 300 microns each, developed in a continuous, relatively crack-free, high-strength vitreous [glassy] phase. “The ceramic nature of the aggregate ensures the product is inert and highly resistant to degradation, thereby providing concrete with a key component that has stood the test of time,” the institute says. “These same properties also render the product environmentally benign in that it can be reused as fill or base material.”

Our Leca (Light Expanded Clay Aggregate ) is an aggregate made of expanded clay which isproduced in rotary kiln at the temperature about 1200 degree centigrade . Yeilding gases which are expanded , form thousands of small bable – like spaces inside the clay and when materials become cold , these bubbles remain and make a coarse surface.

Leca aggregates are round in shape with coarse and course texture. Its exterior color is brown and black with a spongy cellular structure inside. Its sponge- like texture creates a considerable surface area which allows it to bind easily with cementaceous mixtures.
Leca `s most prominent features are: lightness, thermal and sound insulation, moisture impermeability, incompressibility under permanent pressure , non – decompostible, fire resistant , Ph of nearly 7 and , anit-Freezing and high temperature stability.

Four usual gradations are 0-3 mm , 3-10 mm , 10-20 mm and 0-25 mm . Leca bulk dried density for different gradations is general size. lightness of Leca is for the air which exists inside and among the aggregates and depending on size , its amount difers from 73 to 88 percent of total volume . contact with me if need LECA production line: skype: gary102884;   tel: +8615617816797