Process for preparing a pcc composite product

A process for making composite precipitated calcium carbonate particles, the process comprising:

• providing ash particles, at least 25 wt % of the ash particles, on a dry basis, comprising CaO;
• wherein the wt % of CaO is determined by X-ray diffraction;
• and
• wherein the ash particles are the product of incineration;
• forming an aqueous slurry of the ash particles,
• wherein the water used to form the slurry, prior to addition of any optional additives, comprises not more than 500 mg/liter elemental calcium;
• and wherein optional additives that are not sources of calcium comprise not more than 5 wt % of the slurry;
• and
• carbonating the aqueous slurry to form composite precipitated calcium carbonate particles;
• wherein no wet milling is performed;
• and
• wherein
• either
• the only sources of calcium are from the ash particles and the water used in forming the slurry of the ash particles;
• and no source calcium is added to either of the material to be incinerated, or to the incinerator;
• or
• a source of calcium is added to the material to be incinerated, to the incinerator, to both the incinerator and material to be incinerated, at another point in the process, or a combination thereof, such that the ratio of the weight of calcium added, expressed as elemental calcium, to the weight of ash, is not more than 1.0.