DE529384C - Process for dewatering and decomposition of iron vitriol (Fe S Oíñ 7H O) - Google Patents

Description

Process for the dehydration and decomposition of iron vitriol (Fe S 04.7 H2 0) All previous processes for the preparation of iron oxide from iron sulphate by thermal decomposition suffer from the fact that the iron sulphate has a strong tendency to sinter both during drying and during subsequent oxidation Part of the race of the oxidative effect of oxygen is withdrawn and complete decomposition only takes place at a higher temperature; In addition, in all processes, as a result of the high temperatures required, subsequent decomposition of the SO formed occurs, so that the yields have hitherto been quite unsatisfactory.

A method has now been found which overcomes these shortcomings in that, for. a lean agent is added, whereby the entire mass remains loose and porous and the implementation of the drainage, oxidation and decomposition is possible in one operation without z. B. in dr ehöfen caking on the rotary kiln wall would be feared; Z. by adding iron oxide, which acts as a catalyst at the temperatures used, the regression of SO., From OZ and SO, is promoted.

So z. B. when iron oxide is added to the iron sulfate, a mixture is obtained that does not smear or run in the rotary kiln, allows any oxidation process and enables almost complete recovery of the sulfuric acid in the form of SO.

Under certain circumstances, for example with adhering sulfuric acid, it is advantageous to add small amounts of alkali or alkaline earth oxides or hydroxides to the mixture or to add carbonates, whereby on the one hand an evaporation of the acid during drying prevented and on the other hand the decomposition temperature itself is lowered. Example r iron sulfate with 7 aq is with 2o to 3o ° @ "iron oxide, which in the decomposition was obtained, mixed and first in a rotary kiln at Zoo temperatures dehydrated up to 300 °. In this case, care is expediently taken to ensure an oxidizing atmosphere. From here the mixture goes into a second rotary kiln, where it is oxidized Atmosphere is heated to .4oo to 5oo °. \ laughing termination of the oxidation process the material passes through a third furnace, which heats to between 75o and 85o °, for example must become. Of course, the individual stages can also be combined in such a way that that z. B. the oxidation and dehydration in one furnace or the oxidation in one others Oven takes place, or that the entire process takes place in a single oven.

Example e Ferrous sulphate with 7 aq (possibly with the addition of Fe S 0, or, Fe SO ,, 1 aq) is mixed with 100% soda and - depending on the amount of FeSO or FeSO, i aq with 10 to 30 % Iron oxide mixed and treated further as in Example i.

Claims (1)

. 1'nTrixnrisPtzücüE: i. Method of drainage and decomposition of iron vitriol (Fe S0, # 7H.0), characterized in that the drainage and Decomposition in the presence of obtained by thermal decomposition of iron salts Iron compounds is made. a. Method according to claim i, characterized in that that in addition to the decomposition product of iron salts, small amounts of alkali or Alkaline earth oxides, hydroxides or carbonates are added. 3. The method according to claims i and a, characterized in that the drainage and decomposition are always present is made of iron oxide. q .. Process according to Claims i to 3, characterized in that that drying and decomposition is carried out with simultaneous oxidation or that the decomposition is preceded by an oxidation process.