Our six-million-ton crop of sugar beets contains some 12,000 tons of nitrogen, 4000 tons of phosphoric acid and 18,000 tons of potash, all of which is lost except where the waste liquors from the sugar factory are used in irrigating the beet land.  The beet molasses, after extracting all the sugar possible by means of lime, leaves a waste liquor from which the potash can be recovered by evaporation and charring and leaching the residue.  The Germans get 5000 tons of potassium cyanide and as much ammonium sulfate annually from the waste liquor of their beet sugar factories and if it pays them to save this it ought to pay us where potash is dearer.  Various other industries can put in a bit when Uncle Sam passes around the contribution basket marked “Potash for the Poor.”  Wool wastes and fish refuse make valuable fertilizers, although they will not go far toward solving the problem.  If we saved all our potash by-products they would not supply more than fifteen per cent. of our needs.

Though no potash beds comparable to those of Stassfurt have yet been discovered in the United States, yet in Nebraska, Utah, California and other western states there are a number of alkali lakes, wet or dry, containing a considerable amount of potash mixed with soda salts.  Of these deposits the largest is Searles Lake, California.  Here there are some twelve square miles of salt crust some seventy feet deep and the brine as pumped out contains about four per cent. of potassium chloride.  The quantity is sufficient to supply the country for over twenty years, but it is not an easy or cheap job to separate the potassium from the sodium salts which are five times more abundant.  These being less soluble than the potassium salts crystallize out first when the brine is evaporated.  The final crystallization is done in vacuum pans as in getting sugar from the cane juice.  In this way the American Trona Corporation is producing some 4500 tons of potash salts a month besides a thousand tons of borax.  The borax which is contained in the brine to the extent of 1-1/2 per cent. is removed from the fertilizer for a double reason.  It is salable by itself and it is detrimental to plant life.

Another mineral source of potash is alunite, which is a sort of natural alum, or double sulfate of potassium and aluminum, with about ten per cent. of potash.  It contains a lot of extra alumina, but after roasting in a kiln the potassium sulfate can be leached out.  The alunite beds near Marysville, Utah, were worked for all they were worth during the war, but the process does not give potash cheap enough for our needs in ordinary times.

[Illustration:  Photo by International Film Service

IN ORDER TO SECURE A NEW SUPPLY OF POTASH SALTS

The United States Government set up an experimental plant at Sutherland, California, for the utilization of kelp.  The harvester cuts 40 tons of kelp at a load]