Potassium feldspar powder

Potassium is an important element for crop growth. There are many potassium-containing resources in the world, but most of them are water-insoluble or insoluble. Potassium resources are abundant in China, but soluble potassium resources are very poor. Foreign soluble potassium resources are sufficient to meet the needs of agriculture, so there are few studies on making potassium fertilizer from water-insoluble potassium resources. China from the early 1960s began to use potassium feldspar potash fertilizer research, has carried out dozens of technology research, comprehensive can be divided into: sintering method, high temperature melting method, hydrothermal method, blast furnace smelting method and low temperature decomposition method.

General industrial requirements

System of potash use

Potassium oxide (K2O) >9%

Magnesium oxide plus calcium oxide (MgO+CaO) <2%

Sodium oxide (Na2O) <3%

Al2O3> or ≈13% for common ceramics and electric porcelain (China clay and porcelain stone)

Glass ingredients used Al2O3>18%, SiO2 <70%

Abrasive materials

Potassium oxide (K2O) >10%

Silica (SiO2) >60%

Aluminum oxide (Al2O3) >18%

Sintering,

The use of limestone and coal as raw materials, after crushing, after the ball calcination in the vertical kiln, so that the potassium oxide into water soluble, the production cost of this method is low, but the production process of energy consumption, and potassium feldspar potassium conversion rate is low (60%-90%), so that its promotion is hindered.

High temperature melting

On the basis of producing calcium and magnesium phosphate fertilizer, adding 25%-30% potassium feldspar and melting at high temperature (1200-1300 ℃), calcium, magnesium, phosphorus and potassium compound fertilizer was prepared. The product contained 10%-14% available phosphorus (P2O5) and 4%-5% soluble potassium (K2O). The production cost of this method was low.

Hydrothermal method

The potassium feldspar was treated with KOH solution under pressure to make the composition of potassium feldspar K2O·Al2O3 ·SiO2 ·xH2O zeolite-like solid phase. Among them, K2O is soluble, which can be absorbed by plants and is not easy to be lost, and is a kind of slow-release fertilizer. Meanwhile, part of SiO2 also becomes soluble and becomes fertilizer for crops.

Blast furnace smelter

When producing cement, according to the proportion of limestone 81.4%-82%, potassium feldspar 14.2%-15.6%, iron ore 2.6%-3.2%, fluorite 1.1% and coke 3%, the crushed ingredients are mixed into the furnace. When the furnace temperature reaches 1 500℃, the K2O volatilize and is carried out with high temperature air flow. At the same time, K2O acts on the CO2 in the furnace. The product K2CO3 is produced, and the slag discharged from the blast furnace is processed into white cement. This method is limited to cement plant or phosphate plant, as a by-product of potash production.

Low temperature decomposition

Potassium feldspar raw material is crushed to below 6mm by jaw crusher, and the mineral is crushed to below 100 mesh by the ramon mill. The mineral is transported to the pool by the belt conveyor and soaked in CaO water for 20min, and then pumped into the heating and pressure furnace. The temperature in the furnace is controlled at 100-200 ℃, after a certain time, From the furnace outflow into the pool and Na2SO4 mixed immersion, through crystallization, solid-liquid separation and other processes, to get K2SO4, NaOH industrial raw materials.

Potassium feldspar purification

Domestic potassium feldspar resources are rich, but the iron content exceeds the standard, therefore, potassium feldspar iron removal is the key to purification. Iron is magnetic, potassium feldspar is non-magnetic, and the two are easily separated in a magnetic field.

Potassium feldspar raw materials - hand selection - crushing - grinding - classification - dehydration - finished products, this process is suitable for low iron content, good quality raw materials. The use of pre-crusher for coarse crushing and fine crushing, in order to prevent the processing process of iron to potassium feldspar pollution, so, in the selection of grinding equipment easy to use turbine, gravel mill or porcelain ball mill, ultrafine laminating autogenous mill as grinding equipment, the use of spiral classifier to ensure the size of the product. The process is simple and the investment is low. The disadvantage of this process is that the content of iron in the product is difficult to meet the requirements of high quality ceramic products. In order to overcome the shortcomings of the process and increase the magnetic separation process, practice has proved that the selection of wet high gradient magnetic separator iron removal effect is good, iron removal efficiency reaches 70%-90%.

Potassium feldspar fireproof calcium silicate board

The use of potassium feldspar manufacturing calcium silicate board, the principle is the raw material to make good pulp, according to the proportion (potassium feldspar powder: lime: fiber =229:91: 80) mix, good slurry preparation, made the slab flow slurry plate-making process, the slab after piling into autoclaved kettle, high temperature and high pressure steam curing, silica alumina in the materials and the calcium lime in the high temperature water under the action of thermal generating hydrated calcium silicate, crystal hydrated calcium silicate minerals, and fiber cement together to form a whole.

Using potassium feldspar to prepare potassium fertilizer and white carbon black

Potassium feldspar contains 13.6% potassium, according to the characteristics of the remaining mineral stone after potassium extraction, comprehensive utilization of research: The principle of making silica is based on potassium extraction after potassium feldspar structure has been damaged, and then, at a certain temperature and NaOH reaction to make sodium silicate, water dilution at the same time adding appropriate electrolyte, with acid neutralization and temperature aging, and then filtration, washing silica.