Beneficiation and processing technology of soluble potassium salt ore (1)

The main minerals for the preparation of potassium chloride are potash salts and carnallites. The potash salt has a single component, high solubility, and the most simple beneficiation process. Carnallite beneficiation process is more complex, the magnesium chloride must be removed carnallite obtained after further processing sylvite. The processing of sulphate ore is more complicated. In addition to the general beneficiation method, a certain chemical reaction is required to prepare potassium sulphate.
The ore processing method of the potassium salt mine, the chloride type ore usually has the following methods: hot solution method, flotation method, electrostatic method, gravity method, cold decomposition method and cold decomposition-flotation combined method. The basic principles of the various methods are:
The hot solution method utilizes potassium salt and rock salt to have different solubility in aqueous solution at different temperatures for separation. The method is to heat the co-saturated solution of the potassium salt and other salt minerals to a certain temperature, the potassium salt salt all enters the solution, and the solubility of the stone salt is substantially unchanged, and is separated by the solid phase residue, and then the solution is cooled and precipitated. Potassium chloride.
The flotation method is to sort by using the difference in surface wettability between potassium salt and stone salt. The method is to put a collector , a foaming agent, a catalyst and a medium adjusting agent into a saturated solution to form a film on the surface of the potassium chloride to be isolated from the solution, and when the small air bubbles pass, the potassium chloride particles are adsorbed in the bubble. Above, the bubble brings the potassium chloride crystal to the top of the flotation cell, scrapes the foam through the scraper, and is filtered and dried to be the finished product.
The electrostatic method is sorted by the difference in surface charging properties after heating, cooling and other methods of potassium salt and other associated salt minerals. Before sorting, the material is heated to 300-700 ° C, then cooled to 100-200 ° C, or treated with a special modifier to selectively change the charged nature of the mineral surface to achieve the purpose of sorting.
Heavy medium method (or gravity method): Separation in a specific medium by using the difference in density of potassium salts and other salt minerals. The method is to select a suspension solution between the potassium salt and the rock salt density, in which the stone salt is sunk and the potassium salt is floated to achieve the purpose of sorting.
Cold decomposition-flotation combination method: a combination of the above two methods. First, the slurry of the decomposition of carnallite is filtered, and the mother liquor is separated to obtain crude potassium which is similar to potassium salt. The potassium chloride is just separated from the carnallite, has a new ecological surface, and adds a certain amount of water. The product is obtained by flotation, dehydration and drying.
Typical examples of mineral processing are as follows:
1. Yunnan Yanyejing Potash Mine Ore Dressing Process Suiyejing Potassium Salt Mine is a deposit of potassium feldspar salt and stone salt closely coexisting. The main potassium mineral is potassium salt, followed by carnallite. The existing small ore dressing plant of the mine adopts flotation method and processes 24,000 tons of ore annually. The selected ore is mainly a blue-gray type potash salt. The ore containing KCl is generally 10% to 25%, the NaCl content is generally 60% to 80%, the water insoluble matter is 3% to 8%; the original ore has a maximum particle size of 300 mm and the water content is 3% to 6%. The principle of flotation process is shown in Figure 1.

    2. Qinghai Potash Fertilizer Processing Technology in Qinghai Potash Lake, Qinghai Potash Plant, the first plant produces about 40,000 tons of potassium chloride fertilizer per year, and the second plant has an annual output of 200,000 tons of potassium chloride fertilizer. Both of them use carnallite cold decomposition. - Production of potassium chloride by a flotation combined process. The potassium-containing brine is pumped into the salt field, and the carnallite ore is produced by sun exposure, then water is decomposed, and the product is washed by flotation (Fig. 2). The chemical composition of the Yantian carnallite mine: KCl>16%, NaCl<26.25%, MgCl ₂ <25.95%, CaSO ₄ <0.5%, water insolubles 0.2%, free water <2%.

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