Laux process

Lauter vessel, 3 578 Laux process, 79 401 Lavandin oil, in perfumes, 73 368-369 Laver, common and scientific names, 3 188t Lavoisier, Antoine-Laurent, 77 388 Law of mass action, 70 480 Lawrencium (Lw), 7 463-491, 464t electronic configuration, 7 474t Lawsone, in skin coloring products, 7 847 Lawsone (0.25%), cosmetic uv absorber, 7 846t... 

Laux Process. This is a modification of the Bechamp process for the iron reduction of nitrobenzene to aniline which leaves iron oxide as the residue. Incorporation of iron or aluminium chlorides into the reduction process produces high quality yellow and red iron oxide pigments... 

Laux process involving reduction of nitrobenzene (black, yellow, red)... 

Solid-State Reactions of Iron Compounds. Black iron oxides obtained from the Laux process (see below) or other processes may be calcined in rotary kilns with an oxidizing atmosphere under countercurrent flow to produce a wide range of different red colors, depending on the starting material. The pigments are ground to the desired particle size in pendular mills, pin mills, or jet mills, depending on their hardness and intended use. 

Figure 24. Production of iron oxide pigment by the Laux process...

The Laux process is a very important method for producing iron oxide because of the coproduction of aniline it does not generate byproducts that harm the environment. 

The Laux process is a modification of the Bechamp reaction that was discovered in 1854. It has been used for the reduction of nitrobenzene to aniline using metallic iron ... 

Invented in 1926 by J. Laux at Bayer and used commercially thereafter. The Laux process was an improvement on the Bechamp process. 

Fig. 3.3 Production of iron oxide pigments by the Laux process.a) reactor, b) condenser, c) classifier, d) thickener, e) filter, f) dryer, g) mill, h) rotary kiln.

Black magnetite pigments are typically produced either by precipitation from iron salt solutions or by the Laux process. The production processes are described in detail in Section 3.1.1 (Table 3.2, especially Eqs. (3.10), (3.11) and (3.12)). 

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