What is Potassium Chloride?

Potassium chloride (chemical compound KCL) is a type of salt formed from the combination of potassium and chlorine. It is the most common potassium fertilizer obtained from minerals containing potassium.

Potassium chloride is the most important salt among potassium salts, which is available as an ore. In addition, potassium chloride is the most widely used type of potassium salt and it is naturally presents in powder or solid white or pink or colorless crystals. Although this fertilizer is made in several steps, the amount of energy required to produce it is far less than the energy required to make nitrogen and phosphate fertilizers. Potassium chloride contains 60% of potassium, and its solubility in water is about 35%. However, about 92% of the used potassium fertilizers are potassium chloride.

Potassium chloride is used to produce agricultural fertilizers and is a suitable alternative to potassium sulfate fertilizers. This salt can be substantially ionized in water and easily provide the plant with the potassium it needs.

Preparation method of potassium chloride

As mentioned, this material is produced by the reaction between potassium hydroxide and hydrogen chloride. Potassium chloride with the chemical formula KCl is a pink to white mineral salt that can be obtained in one of the following ways:

Extraction from stone mines

Potassium chloride obtained from these mines is usually pinkish-orange due to the presence of impurities such as iron compounds. About 90% of the potassium chloride produced in the world is obtained from these mines. The largest producers of potassium chloride in the world are Canada and Russia, which have huge rock potash mines.

In order to produce potassium chloride, the ore must be concentrated and processed to remove impurities, and potassium chloride is obtained as the final product. In other words, physically, changes have to be made in the ore, and in a few steps, the main material will finally extracted. The first step is to extract the ore and transfer the ore to the factory site, and after storing the ore, it is crushed. Crushing, is also done by large mills that are used to break stones. Mills are usually hammer type. After the material has passed through a vibrating syringe, it is transferred to the next stage, which is the separation of the desired material. Concentration is done at this stage. There are different methods in this field, each of which has its own technology, and their products are different in terms of quality and type of granulation and use in the market. We now describe each of the processes for the production of potassium chloride from ore.

Dry process

This process has six steps as follows:

1. Crushing
2. Separation of slurry containing mineral
3. Dual salt separation
4. Separation of potassium chloride from a combination of two salts
5. Drying
6. Granulation

The ore containing potassium chloride salt with insoluble materials is crushed by thermal methods or by grinding or crushing to a small size, and then by adding water, the slurry containing potassium chloride and sodium chloride salts are separated by thermal precipitation and or by air. In the next step, potassium chloride must be separated from sodium chloride, which is done by flotation, electrostatic separation, or magnetic separation. Potassium chloride is then dried and recovered in an aqueous environment for further purification. It is then granulated and marketed, the recovery of this method is less than 50%.

Wet process

In this process, before crushing the ore, water is added to it, and a slurry is made from the mineral, and then the mineral is crushed, which is done in two different ways:

1. Concentration process of mineral containing potassium chloride using a slurry containing this mineral which has six steps

• Crushing
• Separation of slurry
• Separation of double salts
• Separation of potassium chloride
• Drying
• Granulation

Mineral mixed with water is done by crushing and then separating the slurry by thermal separation or precipitation. The carnallite in the saline solution is then separated or seperated by flotation.

2. Another method is to separate the langbeinite in the solution and separate the potassium chloride from the mixture of the two salts by flotation or gravity separation, and then the potassium chloride is dewatered and centrifuged by filtration or centrifugation. After granulation, potassium chloride is screened as anhydrous crystals, and after granulation, it becomes granular. The product recovery rate in this method is more than 90%.

Extraction of salt brines

These mines are the remnants of old lakes that have dried up over thousands of years. Potassium chloride obtained from these mines is usually white due to the lack of metal impurities.

The initial brine in the mine is drained and collected using canal digging and sent to solar evaporation pools through the pumping station. In the first step, the salt in the brine entering the pools is precipitated by solar evaporation, and then carnallite, which is the feed of the potash processing plant, is extracted. The carnallite produced in the pools is converted to potassium chloride product in 5 main steps (meshing, flotation, decomposition, leaching, drying) in the processing factory.

At present, potassium chloride in Iran uses only brine sources.

Types of potassium chloride

Potassium chloride is sold in three different forms in global markets:

1. Coarse granule size: The superiority of this particle size makes up almost 70% of the total sales. It is consumed as a mixture of the dry mass of potassium chloride.
2. Standard size: This type of product is less considered in the market as long as the dry mix is preferred. A small amount of the standard size is used in chemical fertilizers for plant growth, which is a suspension.
3. Soluble: The use of this product is increasing in the soluble fertilizer industry.

Use of potassium chloride in agricultural fertilizers

Fertilizers containing potassium, nitrogen, and phosphate are all necessary for the growth of plants and can provide them with the number of elements they need. Potassium ions are provided by the composition of potassium chloride in the soil. This salt dissolves in water, and if agricultural lands are irrigated, potash fertilizers are converted into soluble compounds in the soil, which increases their solubility with increasing temperature. Potassium chloride fertilizers in agricultural lands make other nutrients such as nitrates, phosphates, calcium, and essential amino acids available to plants.

The activity of the most important coarse molecules involved in plant cell processes, such as enzymes, chemical catalysts, starches and sugars, can be regulated by the addition of potassium chloride to the soil and the uptake of potassium ions. These fertilizers also have a great effect on the photosynthesis of plants and the absorption of sunlight. This mineral salt is used as a raw material for the preparation of potassium sulfate fertilizers, which is economically viable.

Potassium chloride dissolves well in water, and by irrigating agricultural lands, potash fertilizers are converted into soluble compounds in the soil, which increases their solubility with increasing temperature.

This product is used as fertilizer in agricultural industries. This product is better for plant nutrition than other potassium fertilizers, such as potassium sulfate, because it is found more in nature- a rich source of plant nutrition- and is cheaper than other potassium fertilizers.

About 95 to 96% of chemical fertilizers are composed of potassium chloride. Three main grades are defined for chemical fertilizers.

1- Standard grade, 2- Coarse grade, 3- Granular grade

This grading is done according to the grain size. The grains of 0.2 to 0.8 mm are in the standard grade, 0.8 to 2 mm in coarse grade, and 1.2 to 3.5 mm in granular grade.

Importance of potassium chloride fertilizer in agriculture

About 90 and 98% of the total potassium in the soil is insoluble and resistant to chemical decomposition. Therefore, they can not provide the potassium needed by the plant for optimal growth.

Potassium plays an essential role in all the processes necessary to maintain optimal plant growth. The deficiency of this element reduces the plant's resistance to drought and high and low temperatures. One of the most important effects of potassium deficiency is to reduce plant resistance to pests, pathogens, and nematodes. Therefore, providing a sufficient amount of this element through fertilizers such as potassium chloride helps maintain plant health.

The transfer of potassium inside the plant is from the old tissues to the younger tissues, so the symptoms of potassium deficiency are first seen in the lower leaves of the plant and then, with increasing deficiency, are reached to the upper parts of the plant. One of the most common symptoms of potassium deficiency in plants is yellow burn (chlorosis) of the margins of the leaves or their shedding before maturity.

Potassium deficiency causes slow plant growth and poor root system development. The stems of these plants are weak, and grains such as corn and small seeds show stunted growth. The deficiency of this element causes perennial plants such as alfalfa and grass to be exposed to frost. All of the above can be easily removed using potash fertilizers, including potassium chloride.

Time of use of potassium chloride fertilizer in agriculture

More than 90% of global potash production is used for plant nutrition. Farmers usually use KCL crops on the soil surface in planting rows before planting.

Application properties of potassium chloride (KCL) in the drilling industry

Most of the clays in the builders, especially the Chilean and Marley builders, swell if water is absorbed and then fall off. Due to the fall of the clays during drilling, this factor causes the drilling pipes to get stuck in the hole. Clay constituents have monovalent cations that move easily with other cations. According to the formulation of potassium chloride K+CL-, it can result: If potassium chloride is placed near the clay in the drilling hole, the K+ ion on the surface of the clay replaces the monovalent cation of the clay, and as a result, due to the low hydration of potassium, the clay remains more stable, and the swelling of the clays is prevented by filtering the drilling mud (water loss). In other words, they are widely used as inhibitor in Chilean and Marley manufacturers.