Übersetzung für "Coarse aggregate" in Deutsch

Since the building material in question, in particular if it is concrete, contains coarse aggregate materials to a large extent more or less, the tools of the positive mixer must be protected from possible damage caused by jammed constituents of the building material mixture.

In a more alkaline medium, premature flocculation of the polymer usually occurs, and this leads to a coarse aggregate.

Another important disadvantage resides in that such pastes cannot be used at all if the initial moisture content of sand and coarse aggregate used in making concrete is so high that an addition of water even in the form of aqueous concrete pastes will intolerably reduce the consistency of the concrete.

Depending on the prevailing climatic conditions, the coarse aggregate is exposed by brooming the surface just a few hours after placing the concrete pavement.

This mastic asphalt, which has improved noise qualities, is processed at 10 to 13 kg/sqm of scattered stone chippings (coarse aggregate) having special properties with respect to grain size and shape.

The amount of powder (particles with grain size 0,25 mm) rises up to 700 kg/m³ while the amount of coarse aggregate decreases.

The amount of powder (particles with grain size 0,25 mm) rises up to 700 kg/m3 while the amount of coarse aggregate decreases.

That is, when overlaying the bottom, the underlying layer is applied with a mixture of coarse aggregate, and the upper alignment layer - fine.

In the prototype emulsion (PFOB-1), such coarse aggregates obviously were missing.

This is especially suitable for flattening and crushing coarse soil aggregates in seedbed preparation.

Relatively coarse aggregates collect in the center of the “material-flow kidney” formed during pelleting.

An appropriate amount of the strongly acidic buffer solution is then added to the dry residue, and the mixture is stirred at elevated temperature until a homogeneous colloidal solution which is free of coarse colloidal aggregates has formed.

They are usually used for the preparation of mineral building materials, such as mortars or concretes, by adding finely divided or coarse aggregates, such as sand or stones, during mixing with water.

These large coarse TiO2 aggregates are not suitable for pigment production without prior disintegration because their hardness would deteriorate the dispersibility of the pigment and their relatively broad range of sizes would deteriorate optical properties such as tinting strength and hiding power.

The coarse titanium dioxide aggregates produced by the process of the invention are used as scrubbing solids to prevent the formation of deposits in the production of titanium dioxide by vapor phase oxidation of titanium tetrachloride while the fine-particle titanium dioxide is processed to pigment product in the usual way.

OBJECTS AND SUMMARY OF THE INVENTION A primary object of the invention therefore was to develop an improved process for the production of coarse TiO2 scrubbing solids at the highest possible yield within the process of vapor phase oxidation of titanium tetrachloride, the hot reaction mixture being cooled, the titanium dioxide being separated from the gaseous reaction products and the coarse TiO2 aggregates being separated from the TiO2 fines and used as scrubbing solids in the same production process.

The process can be carried through in such a way that the quantities of coarse scrubbing TiO2 aggregates per unit of time consumed by abrasion and newly formed by sintering are equal, their percentages in recycling TiO2 thus remaining constant which simplifies the TiO2 production process.

The foregoing object has been achieved by the present invention by the development of a process for the production of coarse scrubbing aggregates of titanium dioxide particles by vapor phase oxidation of titanium tetrachloride with an oxygen-containing gas, coarse TiO2 scrubbing aggregates being commingled with the hot reaction mixture, the reaction mixture being cooled indirectly, the titanium dioxide being separated from the gaseous reaction products, the coarse titanium dioxide aggregates being separated from the TiO2 fines, recovered and returned as scrubbing solids to the hot reaction mixture.

In finely pulverulent filling compounds, for example, on which floor coverings are to be laid after application, relatively coarse aggregations are however not acceptable since they are perceptible on the surface of many smooth floor covering materials.

Additions of 0.01 to 0.30% by weight alkali hydroxide (relative to anhydrous TiO2) and calciner temperatures of 700°-1000° C. enable the production of coarse, hard TiO2 aggregates of sizes between 0.15 and no more than 4 mm, preferably between 0.2 and 2 mm, which can be returned to the heat exchanger to impart abrading action.

However, in fine-particle primers, on which floor coverings are to be laid after application, relatively coarse aggregations are unacceptable because they show up on the surface of many smooth floor covering materials.

With such coarse aggregates in the seedbed, the air flows become turbulent and the seedbed dries out.

As a result of the high fluidity of such concrete mixtures, however, segregation of the coarse aggregates and the separation of bleed water on the surface would occur.

The lower the fines content of the highly fluid mixture, the higher is the tendency for segregation of the coarse aggregates and bleeding.