Kronos, Inc.

Kronos Titan-g.m.b.h.

Kronos Titan Gmbh & Co. Ohg

Dieter Schinkitz

Achim Hartmann

Hans Thumm

Achim M Kulling

Edgar Klein

Ulrich Rothe

Nickel and lead ions are eliminated from an acidic concentrated iron(II) salt solution by adding an alkali sulfide and precipitating nickel and lead sulphides.

Method for eliminating nickel ions and lead ions from ferrous salt solutions

A process for purifying an acidic technical-grade iron chloride solution formed from cyclone dust from the production of TiO.sub.2 in accordance with the chloride process by adjusting the pH with a first neutralizing agent and thereafter introducing the pH adjusted solution in a controlled manner into a solution containing a second neutralizing agent. In this process undesired ions which are to be separated, such as chromium, vanadium, zirconium and/or niobium, precipitate in the form of efficiently filterable hydroxides which can be separated industrially under economical conditions by filtration. The filter cake is non-hazardous and can safely be disposed of by dumping. Calcium carbonate is the preferred neutralizing agent, and the pH adjustment may also advantageously be effected by using scrap iron or by using iron sinters with reduction of any Fe(III) ions before the second neutralization step.

Process for purifying a technical iron chloride solution by selective

In order to treat metal chlorides obtained in the form of dust collector solids in the production of titanium dioxide by the chloride process, the inert constituents, especially particulate coke, is separated then the metals are selectively precipitated and a maturing phase under oxidative conditions is provided for. The residue consisting of metal hydroxides is also not thixotropic in the absence of inerts. As a result, the material to be deposited has been cut in half.

Process for the production of disposable products from metal chlorides

For economical and assured separation of chromium, vanadium and titanium ions from acidic waste waters, which accrue in great quantities in preparation of titanium dioxide, the pH is first raised to around a value of 3 by addition of dolomite brick powder. Directly thereafter, the pH is fine tuned into the range of 4.3 to 4.7 through addition of calcium hydroxide and/or sodium hydroxide, and the hydroxides are separated with the aid of a flocculating agent. Since iron ions and calcium ions remain mainly dissolved in the waste water through such selective precipitation, only a relatively small volume of slush has to be disposed of.

Separation of heavy metals from waste water of the titanium dioxide

The invention provides an apparatus for the conditioning of sludges comprising two vertically arranged cylindrical vessels. An overflow pipe connecting the two cylindrical vessels is installed tangentially to the upper portions of the cylindrical vessels and may be provided with a detachable coupling. A sludge feed pipe is connected to the first cylindrical vessel and is installed in a direction tangentially opposite the overflow pipe above the bottom of the first vessel. A feed tube is installed tangentially into the sludge feed pipe. Two additional feed tubes are installed tangentially into the overflow pipe. A discharge pipe is installed in a direction tangentially opposite the overflow pipe above the bottom of the second vessel.

Apparatus for the chemical conditioning of sludges

The application is concerned with a process for the manufacture of an aqueous iron (III)-chloride-sulfate solution by the oxidation of iron (II) sulfate with chlorine in aqueous solution.

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Leverkusen, Germany

Dieter Schinkitz