US1944529A

US1944529A - Flotation process

Info

Publication number: US1944529A
Application number: US651228A
Authority: US
Inventors: Schafer Wilhelm; Mertens Willy
Original assignee: ERZ und KOHLE FLOTATION GmbH
Current assignee: ERZ und KOHLE FLOTATION GmbH; ERZ- und KOHLE-FLOTATION GmbH
Priority date: 1931-09-26
Filing date: 1933-01-11
Publication date: 1934-01-23
Anticipated expiration: 1951-01-23

Description

Patented Jan. 23, 1934 os-Pics 1,944,529 v ino'rs'rron raocass c Wilhelm. Schifer and Willy Mertens, Bochum,

Germany, assignors to 1312- und Kohle-Flota- Gesellschaft mit tion Bo'chum, Germany beschrankter Bathing, v

:No Drawing. Application January 11, 1933, serial 113151051328, and in Germany September 26,

16 Claims. (01. 209-160) a This invention relates to froth-flotation of coal, for the purpose to separate the fusain from the other structural constituents of coal namely 'vitrain, clarain and durain.

According to the United States Patent No. 1,499,872, it isknown to render the fusain', which is present in nearly all coals and has an adverse influence on coking, wettable and nonfloatable by the addition of protective colloids such as starch, tannin, albumen or glue, to thecoal slurry in the preparationfof the coal by the flotation .process, whereby itis. necessary to regulate the amount. of said protective colloids so that the other structural constituents of the coal retain their floatable capacityq nd can be floated out as a product low in fusain. These processes have the drawback of being extremely delicate, in

consequence of which the separation of the fusain from the other structural constituents of the coal is usually incomplete. If, for example, the requisite concentration of the protective colloids be slightly exceeded, the depressing action of the protective colloids extends, to a certain extent,

to the vitrain and durain which then partly pass away together with the fusain. If the concentration of the protective colloids be too low, a

a portion of the fusain will be left in the vitrain and the desired degree of separation will not water.. These agents may be organic acid chlo- Y be attained.

The object of the present invention is to provide a flotation process enabling'the separation of the fusain from the other structural constituents to be effected in a less delicate and more complete manner.

According to this invention fusain is separated from the other constituents of coal in a frothfiotation process by adding to the pulp in presence of a froth producing reagent a protective colloid which depresses the durain, vitrain and clarain without afiecting the floatability of fusain. The protective colloids which can be used in carrying out this invention may be polyhexoses [(CsHmOs); such as starches or dextrins] which have been pre-treated with hydrogen-chloride.

The most effective result can be obtained in treating starches or dextrins with hydrogenchloride in nascent state by adding agents which split off hydrogen-chloride when treated with rides (such as acetylchloride and benzoylchloride) or some suitable inorganic chlorides (such as AlCls and ZnCls).

It has been ascertained that starches or dextrins, pre-treated in the described manner, form "suitable additions which do not affect the float exceed those required to efiect the depression of 35 the vitrain and durain constituents, it can be extensively floated ofi after adding a frothlng agent, whilst the other structural constituents of the coal remain unfloatable. The froth producing agents which can be used for the separa- 7 tion of the fusain may preferably be wood-tar oils of low boiling point (105-160 Cels.) whilst wood-tar oiis of higher boiling point would partly neutralize the depressing action of the protective colloids. After separating the froth containing the fusain, theremaining pulp after the addition of a slightly dissociated alkali and one or more suitable frothing agents is' subjected to a second froth-flotation operation adapted to separate the so durain, vitrain and clarain from the waste. The addition of a slightly dissociated alkali to the pulp after the removal of the fusain has the eifect of again rendering the other structural constituents floatable. These constituents-can a then be floated. off as a product that is low in ash and practically free from fusain with the result, that the recovery can be raised to amaximum because there is no longer any need to take into consideration the chance of fusain being ner and the resulting froth containing the iusain in a concentrated condition is removed while the other structural constituents of the coal remain I in the pulp. After the fusain has been removed,

'the slurry is treated with slightly dissociated alkalis, such as. sodium carbonate or waterglass, until dye reaction is neutral or slightly alkaline.

.Finally, the other structural constituents are u.

floated off by the addition of the known oils suitable for coal flotation.

The manner in which the polyhexose pro-treated with hydrogen-chloride, act in the separation of the fusain from the other structural constituents of the coal, by the flotation process, will be evident from the following examples:-

Example 1.-1000 grams of coal slurry from a Ruhr colliery and with a solid: liquid ratio of 1:4,

were treated with 0.2 grams of dextrin (pre- Product Weight it) Ash 7,) Ash (kgs) Fusaiu product Coal wcowo w-qcc Raw coal The fusain product has'no caking capacity and cannot be coked. On the other hand, the coal product exhibits excellent caking capacity and furnishes a firm microporous coke.

Example 2.-1000 grams of dust coal from an English coal deposit were stirred for several 'minutes with about 3 parts of water and the addition of 0.15 grams of starch (pre-treated with acelyt chloride), and then floated with the addition of 4 drops acetone-light oil boiling point 105-140 Cels.). After the removal of a fusain product, as the first batch of foam, the vitrain and fusain were floated off with addition of 0.3

Products Weight (76) Ash(%) Ash (kgs.)

Fusain product Goal F F i- Mu eum The fusain product exhibited poor cakingcapacity whilst on the other hand, that of the coal product was very good.

Example 3.-In the flotation of a slurry of Silesian coal the fusain product was first floated off, with addition of 0.2 grms, of dextrin (-pretreated with zinc-chloride), the flotation of the vitrain and fusain constituents being then effected after addition of 0.4 grms of waterglass and 5 drops of coaltar oil. The results. are given in the following table:-

Product Weight Ash 9; Ashrk s.)

The recovered fusain product cannot be coked, whereas the coal product furnishes excellentcoke. It is evident from the above example that the new flotation process is generally applicable to -,the separation of the fusain from the'other structural constituents of coal. In addition to the examples given, in which coals from the Ruhr, Silesian and English coal districts were-treated, 80 experiments were also conducted with coal from Saxony, the Sarre district and Czecho-Slovakia,

and furnished similar good results in respect of separation.

I The quantity of pre-treated dextrins and starches required for carrying out the-"process ranges in general, between 100 and 300 grams wherein heterogeneous coal is made into 'a'pul-p with water and subjected to froth-flotation separation in the presence of a froth producing reagent and of a polyhexose which has been pretreated with hydrogen-chloride.

2. A flotation process for separating fusain from the other structural constituents of coal,

'wherein heterogeneous coal is made into a pulp with water and subjected to froth-flotation separation in the presence of afroth producing reagent and of a polyhex'ose which has been pretreated with hydrogen-chloride in nascent state by adding agents which split ofi hydrogen-chloride when treated wit water.

3. A flotation process for separating fusain from the other structural constituents of coal, wherein heterogeneous coal is made into a pulp with water and subjected to froth-flotation separation in/ the presence of a froth producing n reagent and of a polyhexose which has been pretreated with inorganic chlorides which split off hydrogen=chloride when treated with water.

4. A flotation process for separating fusain from the other structural constituents of coal, wherein heterogeneous coal is made into a pulp with water and subjected to froth-flotation separation in the presence of a froth producing reagent and of a polyhexose which has been pretreated with organic acid chlorides.

5'. A flotation process for separating fusain from the other structural constituents of coal, 1,20v wherein coal is'made into a pulp with water and subjected to a froth-flotation separation in the presence of a froth producing reagent and of starch which has been-pre-treated with hydragon-chloride. 13

6. A flotation process for separating fusain from the other structural constituents of coal, wherein coal is made into apulp with water and subjected to a froth-flotation separation in the presence of a truth producing reagent and 01 starch which has been pre-treated with hydrogen-chloride in nascent state by adding agents which split oif hyrogen-chloride when treated wherein coal is made into a pulp with water and subjected to a froth-flotation separation in the presence of a froth producing reagentand of starch which has been pre-treated with organic acid chlorides. v

9. A flotation process for separating fusain from the other structural constituents of coal, wherein heterogeneous coal is made into a pulp with water and subjected to a froth-flotation operation in the presence of a froth producing reagent and of dextrins which has been pretreated with hydrogen-chloride. I e

10. A flotation process for separating fusain from the other structural constituents of coal, wherein heterogeneous coal ismade into pulp with water and subjected to a froth-flotation operation in the presence of a froth producing reagent and of dextrins which has been pretreated with hydrogen-chloride in nascent state by adding means which split off hydrogen-chloride when treated with water.

11. A flotation process for separating fusain from ithe other structural constituents of coal, wherein heterogeneous coal is made into a pulp -with water and subjected to a froth-flotation operation in the presence of a froth producing reagent and of dextrins which has been pretreated with inorganic chlorides which split off hydrogen-chloride when treated with water.

12. A flotation process for separating fusain from the other structural constituents of coal, wherein heterogeneous'coal is made into a pulp with water and subjected to'a froth-flotation operation in the presence of a froth producing reagent and of dentrins which has beenpretreated with organic acid chlorides.

13. A flotation process for separating fusain from the other structural constituents of coal, wherein heterogeneous coal is made into a pulp with water and subjected to a froth-flotation operation in the presence of a small quantity of wood-tar oil of low boiling point and of a polyhexose which has been pre-treated with bydrogen-chloride. V

14. A flotation process for separating fusain from the other structural constituents of coal, wherein heterogeneous coal is made into a pulp with water and subjected to a froth-flotation operation in the presence of a froth producing reagent and of a polyhexose which has been pretreated with hydrogen-chloride'; separating the froth containing the fusain and adding to the remaining pulp slightly dissociated alkalis for the purpose of again rendering the other structural constituents floatable.

15. A flotation process for separating fusain from the other structural constituents of coal,

wherein heterogeneous coal is made into a pulp with water and subjected to a froth-flotation operation in the presence of a small quantity of wood-tar oil of low boiling point and of a polyhexose which has been pre-treated with hydrogen-chloride; separating the froth contain ing the fusain and adding to the remaining pulp slightly dissociated alkalis for the purpose of again rendering the other structural constituents floatable.

16. A flotation process for separating fusain from the other structural constituents of coal, wherein heterogeneous coal is made into a pulp with water and subjected to a froth-flotation operation in the presence of a froth producing reagent and of a polyhexose'which has been pretreated with hydrogen-chloride; separating the froth containing the fusain and again subjecting the remaining pulp after the addition of a slightly dissocc. .ted alkali and a frothing agent to a flotation operation to separate the durain, clarairi and vitrain from the waste.

WILL-Y MERTENS.