The present application relates to aqueous slurries comprising precipitated calcium carbonates having a bimodal particle size distribution with a first maximum in particle size distribution and a second maximum in particle size distribution, as well as methods for making them and their uses.

Provided herein are methods and systems to form calcium carbonate comprising vaterite, comprising dissolving lime in an aqueous base solution under one or more precipitation conditions to produce a precipitation material comprising calcium carbonate and a supernatant solution, wherein the calcium carbonate comprises vaterite.

A composite powder containing microstructured particles obtainable by means of a method in which large particles are combined with small particles, wherein the large particles have an average particle diameter within the range from 0.1 μm to 10 mm, the large particles comprise at least one polymer, the small particles are arranged on the surface of the large particles and/or distributed inhomogeneously within the large particles, the small particles comprise sphere-shaped precipitated calcium carbonate particles having an average diameter within the range from 0.05 μm to 50.0 μm, wherein the sphere-shaped calcium carbonate particles are obtainable by means of a method in which
a. a calcium hydroxide suspension is initially charged,
b. carbon dioxide or a carbon dioxide-containing gas mixture is introduced into the suspension from step a. and
c. resultant calcium carbonate particles are separated off,
with 0.3% by weight to 0.7% by weight of at least one aminotrisalkylenephosphonic acid being further added. Preferred application areas of the composite powder encompass its use as additive, especially as polymer additive, as additive substance or starting material for compounding, for the production of components, for applications in medical technology and/or in microtechnology and/or for the production of foamed articles. The invention therefore also provides components obtainable by selective laser sintering of a composition comprising a composite powder according to the invention, except for implants for uses in the field of neurosurgery, oral surgery, jaw surgery, facial surgery, neck surgery, nose surgery and ear surgery as well as hand surgery, foot surgery, thorax surgery, rib surgery and shoulder surgery. The invention also provides the sphere-shaped calcium carbonate particles which can advantageously be used to produce the composite particles according to the invention, and the use thereof.

Effluent water is combined with carbon dioxide sourced from a carbon dioxide-containing emission stream to produce a reaction solution. The pH of the reaction solution is controlled to induce precipitation of a carbonate salt from the reaction solution.

The present invention relates to a process for the separation of strong acid from its salts. In said process, a strong acid salt is reacted with organic weak base (OWB) in the presence of a hydrophilic solvent and CO.sub.2. The cation of the strong acid salt is precipitated to produce a carbonate/bicarbonate salt and the strong acid form a liquid salt with the OWB. The above process is performed in a solution comprising both the strong acid salt and the WBO. In the next step, the strong acid is released from its OWB liquid salt and the OWB is returned to a previous step.

Techniques for growing crystalline calcium carbonate solids such that the crystalline calcium carbonate solids include a volume of 0.0005 mm.sup.3 to 5 mm.sup.3, include a slaker to react quicklime (CaO) and a low carbonate content fluid to yield a slurry of primarily slaked lime (Ca(OH).sub.2); a fluidized-bed reactive crystallizer that encloses a solid bed mass and includes an input for a slurry of primarily slaked lime, an input for an alkaline solution and carbonate, and an output for crystalline calcium carbonate solids that include particles and an alkaline carbonate solution; a dewatering apparatus that includes an input coupled to the crystallizer and an output to discharge a plurality of separate streams that each include a portion of the crystalline calcium carbonate solids and alkaline carbonate solution; and a seed transfer apparatus to deliver seed material into the crystallizer to maintain a consistent mass of seed material.

The present invention is directed to a process for producing precipitated calcium carbonate with improved resistance to structural breakdown, wherein the milk of lime is carbonated in the presence of at least one gas other than carbon dioxide, or the carbonation is carried out in the presence of a static gas bubble comminution unit as well as to precipitated calcium carbonate obtained by such a process.

A composite powder containing microstructured particles having inhibitory calcium carbonate, obtainable by means of a method in which large particles are combined with small particles, wherein the large particles have an average particle diameter within the range from 0.1 μm to 10 mm, the large particles comprise at least one polymer, the small particles are arranged on the surface of the large particles and/or distributed inhomogeneously within the large particles, the small particles comprise calcium carbonate particles, the small particles have an average particle size within the range from 0.01 μm to 1.0 mm,
wherein the small particles are obtainable by means of a method in which calcium carbonate particles are coated with a composition comprising, based on its total weight, at least 0.1% by weight of at least one weak acid.

Preferred application areas of the composite powder encompass its use as additive, especially as polymer additive, as additive substance or starting material for compounding, for the production of components, for applications in medical technology and/or in microtechnology and/or for the production of foamed articles.

The invention therefore also provides components obtainable by selective laser sintering of a composition comprising a composite powder according to the invention, except for implants for uses in the field of neurosurgery, oral surgery, jaw surgery, facial surgery, neck surgery, nose surgery and ear surgery as well as hand surgery, foot surgery, thorax surgery, rib surgery and shoulder surgery.

The invention relates to a method for producing an implant by means of a composite powder having micro structured particles having inhibiting calcium carbonate, wherein the composite powder is obtained by a method in that large polymer particles are joined to small calcium carbonate particles, wherein the calcium carbonate particles are obtained by a method in that calcium carbonate particles are coated with a composition which, in each case based on the total weight thereof, comprises a mixture of at least 0.1 wt % of at least one calcium complexing agent and/or at least one conjugated base which is an alkaline metal or calcium salt of a weak acid, together with at least 0.1 wt % of at least one weak acid.

The present invention relates to a method for the production of granules comprising surface-reacted calcium carbonate, as well as to the granules obtained thereby and their use.