US1917945A - Process of making ferric sulphate - Google Patents

Description

July l1, 1933. H. s, MARSH Er Al. A 1,917,945 PROCESS OF MAKING FERRIC SULPHATE u Filed Deo. 14, 1928 Ferrous Sup/m@ (5,0504 7,@7 o) Heaz ao 400-`0 /L- o make a/vyaraas fer/fou; @da/7a e (@1704) f/ha lZo 60 mesh Patented July 11, 1933 UbiTED STATES PATET @F.FIC

S. MARSH AND CARL W. WEESNER, .OF YOUNGSTOWN, OH-IO, ASSIGNGR-S TO SHARON STEEL H001? COMPANY, OF SHARGN, PENNSYLVANIA, A CORPORATION OF PENNSYLVAIA PROCESS OF MAKING FERRIVC SULPHATE Application filed December 14, 1928.

This invention reates to a process of producing ferrie sulphate from ferrous sulphate. lt relates more particularly to a process of producing ferrie sulphate from ferrous sulphate having water of crystallization.

The accompanying drawing is a flow sheet which illustrates the process.

In Patent No. 1,589,610, granted J une 22, i026 to Henry S. Marsh and Ralf S. Cochran for a method of Reclaiming spent pickling solutions, there is disclosed a method of obtaining copperas crystals from the spent pickling solution. The wet copperas crystals obtained in accordance with the patented process contain seven molecules of water of crystallization. These copperas crystals may be heated to a temperature of 9.120 F. or higher in order to produce dry copperas crystals having' one molecule of water of crystallization.

The present invention has for one of its objects the production of ferrie sulphate from dry crystals of ferrous sulphate no matter in what manner the dry ferrous sulplate or copperas crystals are obtained. One method of obtaining dry copperas crystals having seven or less than seven molecules of water of crystallization is by heating the wet copperas crystals obtained by the patented process above referred to.

Tn accordance with the present invention ferrous sulphate (oopperas) crystals containing water of crystallization are heated to a temperature suflicient to drive off all of the water of crystallization and render the crystals substantially anhydrous. This may be accomplished by heating to a temperature of 400-6000 F. and preferably by heating to a temperature of about 4500 F. This heating, which renders the crystals anhydrous, produces a very friable material which can be easily crushed. The friable material is then iinely divided by any grinding means, for example, by crushing it between two steel rollers having smooth surfaces. It is preferable to grind the material to a size such that it will pass through a sieve having meshes to the inch. The ground ferrous sulphate is then heated un- Serial No. 326,151.

der oxidizingconditions to a temperature sufficient to convert it into ferrie sulphate and ferrie oxide. This may be accomplished by heating it in a rotary furnace of the open muflle type to a temperature of 850- 925 F., preferably about 900 F. If temperatures higher than these are employed the ferric sulphate tends to decompose, resulting in the formation of an excess quantity of ferric oxide. If lower temperatures are employed some ferrous sulphate will remain unconverted. Y

The material discharging from the 'rotary furnace contains about ferric sulphate and about 20% ferric oxide, the ferrie oxide having been formed during the heating step in which the material within the kiln had access to the oxygen of the air. The material coming from the kiln is then further treated in order to convert the ferrie oxide into ferric sulphate. This may be accomplished by treating the material with a substance containing a sulphate radical. It is preferred to use sulphuric acid for this conversion. The material discharged from the rotary furnace is introduced slowly while stirring into a dilute solution of sulphuric acid. Since during this addition heat is evolved, it is preferred to cool the mixture by any desired means. If the material is added too rapidly to the acid a jellylike mass is formed which is very diflicult to control. The addition should, therefore, be made very slowly with constant stirring and cooling of the mixture so that a mushy somewhat liquid and flowable mass is obtained which can be more easily handled and managed than the jellylike mass which would be produced manner of carrying out our process.

erric sulphate is indicated by the mass changing from a red to a straw or white color. The heating is continued until the mass is thoroughly dry, after which the product is ready for use.

We have described the present preferred It is to be understood however that the process may be otherwise practiced without departing from the spirit of the invention or the scope of the appended claims.

Ve claim:

1. In the process of making ferric sulphate, the steps which comprise heating anhydrous ferrous sulphate in the presence of oxygen to about 900 F. to convert it into icrric sulphate and erric oxide, slowly introducing the mass into sulphuric acid while stirring, and heating the resulting mass to accelerate the reaction.

2. In the process of making ferrie sulphate, the steps which comprise heating tine ly ground anhydrous ferrous sulphate in the presence of oxygen to a temperature oi? S- 9250 F. to convert it entirely into erric sulphate and erric oxide, and slowly introducing the resultant product into sulphuric acid while stirring, and heating the resulting mass to accelerate the reaction.

3. The process of making erric sulphate from ferrous sulphate having water of crystallization, which comprises heating the ferrous sulphate to a temperature of S50-925 F. to convert it entirely into ferric sulphate and ferrie oxide, treating the resultant prod uct with sulphuric acid to transform the ferrie oxide to erric sulphate, and heating the resulting mass to about 500 F. to vaccelerate the reaction.

4. In the process of making erric sulphate, the steps which comprise heating linely ground anhydrous 'iierrous sulphate in the presence of oxygen to a temperature of S50-9250 F. to convert it into a mixture containing about 80% ferrie sulphate and about 20% ferrie oxide, slowly introducing the mixture into a. dilute solution of sulphuric acid while stirring and cooling to convert the ferrie oxide into ferrie sulphate, heating the mixture to about 300-S50o F. to accelerate the reaction, and thereafter continuing tlhe heating until the mass is substantially c ry.

In testimony whereof we have hereunto set our hands.

HENRY S. MARSH. CARL W. VEESNER.

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