CALIFORNIA SALT | AdventAI

International Tract and Missionary Society · Oakland, Cal. · Jul 15, 1889

FromSigns of the Times, Vol. 15, No. 27.

CALIFORNIA SALT.

THE most important mineral industry in Alameda County is the recovery of salt from the waters of San Francisco Bay. This business is carried on extensively upon the east shore of the bay, in the neighborhood of Alvarado and Mt. Eden. At the former place Messrs. Plummer, Barton, Quigley, and others have their works; at Mt. Eden are the works of P. Marsicano and the Union Pacific. Two methods are employed in Alameda County for the recovery of salt from sea-water. One is by complete natural evaporation and gathering the residue; the other by allowing tanks of sea-water to evaporate until a saturated solution is obtained, from which the salt is recovered as it crystallizes.

The first process is in use in the salt-ponds of the Messrs. Quigley of Alvarado. At these works a pond covering 400 acres and surrounded by a levee, is filled with sea-water at spring tide. This pond is divided into tanks. There are three tanks side by side, covering an area of 400 acres. As the density of the water in the tanks increases by evaporation, it is pumped by windmills from the two outside tanks to the center one until it is filled with strong brine. This brine is then pumped into a reservoir of thirty to forty acres in extent, which is filled to a depth of twelve to thirteen inches.

Here the density of the liquid rapidly increases, and the salt commences to crystallize. When a crust one and a half inches in thickness has formed upon the floor of the pond, the salt is scraped up. After gathering the salt, whatever mother liquor (bittern) remains is run off, no effort being made to recover any of the elements it may contain. The best and whitest salt is obtained in warm, windy weather, the wind forming ripples in the solution, which wash the rapidly forming crystals. In still, hot weather the salt has a yellow tinge. It takes about three years for a pond to get into a suitable condition for the production of salt. In that time a peculiar "skin" grows over the bottom, thus protecting the solution from contamination by earthy matter. These works have been running for twenty years. Their output has been from 2,500 to 3,000 tons per annum. The second process is in use at the California and Union Pacific Salt Works, in the vicinity of Mt. Eden.

The works of the California Salt Company are situated about half a mile southwest from Mt. Eden railroad depot. The plant consists of fifty salt ponds, which are arranged in "schools" (rows), together with several large reservoirs, one of which is three miles in circumference, the whole covering 2,000 acres of land. The sea-water is let into the larger reservoirs, and from there is pumped by windmill into the smaller ponds, and from one pond into another, each pond increasing in the density of its solution. When a saturated solution has been obtained, the salt crystallizes upon the surface; it then falls to the bottom of the liquid, where it accumulates. When it has collected to a depth of three or four inches, it is raked out and piled on platforms to dry. The crude material thus obtained is shipped from these works to San Francisco, where it is manufactured into the finer grades of salt by the American Salt Company. In their works the salt is placed in galvanized iron driers, heated by steam, each drier having a capacity of twenty-two tons per day. When thoroughly dried it is ground in burrmills to various degrees of fineness, for dairy and household use. The capacity of the California Salt Works at Mt. Eden is 15,000 tons per annum; that of the mills of the American Salt Company, in San Francisco, 1,200 tons per month.—Pacific Rural Press.